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December 24, 2008

Science and the Environment

Posted by John Baez

As the year’s end approaches and I hole up at home, free of the pressures of teaching, my thoughts roam a bit more freely. So, they naturally turn to questions like this: am I doing the right things?

For example: should I do more to help save the planet? And if so, how can I do it in a way that takes advantage of my special skills? An education in math and physics leads people to value simple, elegant problems. The ecological crisis we face is anything but: it’s an incredible mess. Is there anything a mathematical physicist can do to help that a biologist or politician can’t do better? I try to proselytize on my webpage, but is that enough?

Questions like this don’t fit comfortably into this blog. So, I apologize to readers who prefer the usual fare. But these questions seem too important to completely ignore — and they’re especially timely for this reason:

In just a few weeks, science policy in the US may be run by scientists.

Here’s what’s happening:

Barack Obama appointed Nobel laureate physicist Steven Chu as head of the Department of Energy. On May 9, 2007, Chu said "If I were emperor, I would put the pedal to the floor on energy efficiency and conservation." As director of the Lawrence Berkeley National Laboratory, Chu pushed scientists to develop technologies to reduce greenhouse gas emissions.

Obama appointed MacArthur prizewinner and Woods Hole director John Holdren to be his science advisor. Holdren recently compared our current approach to climate change to:

being in a car with bad brakes driving towards a cliff in the fog.

In the October issue of Scientific American, Holdren wrote:

Unfortunately, the Bush administration has wasted the last eight years. It should have been taking decisive action but engaged instead in systematic understatement of the danger: it has made ridiculous assertions that the U.S. should not do anything that China does not agree to do and has stubbornly insisted that no action should be taken to improve climate change ‘if it hurts the economy.’ This last rationalization translates into ‘if it costs anybody any money’ and is roughly akin to saying that the country should not defend itself against terrorism because that costs money.

He recently gave this speech at Harvard:

He begins by explaining the problem and its causes. Then, starting on page 30 of the PDF file of his speech, he describes what we can realistically do. The short answer: there’s no panacea; we need to pursue many strategies. But the "cheapest, fastest, cleanest, surest source of emissions reductions is to increase the efficiency of energy use in buildings, industry and transport."

Obama has also appointed the MacArthur prize-winning zoology professor Jane Lubchenco to head NOAA, the National Oceanic and Atmospheric Administration, which does most of the US government research on climate change, and regulates fisheries.

Lubchenco recently gave this speech:

She says that her research in oceanography started out being fun, and intellectually challenging:

I received my PhD from Harvard in 1975, and was steeped in the culture of the ivory tower. My mentors, at Harvard, the University of Washington, and a research group that I spent a lot of time with at the University of California at Santa Barbara, were collectively the most stellar ecologists in the field. I have just a really impeccable pedigree if you want to count those kinds of things. My mentors were very much focused on doing your science, publishing in the scientific literature, getting grants, and pushing the intellectual frontiers of the discipline. That was what we did. It was exciting, it was fun, it was tremendously challenging, and it was very, very rewarding. I think this is fairly typical of a lot of scientists of my generation.

But then things started to change:

Over time, many, many ecologists observed that the systems they were studying were changing before their very eyes. Ecologists that would go back to the same places year after year after year started seeing changes that had not been documented before. The changes were different, they were happening faster, and many more ecologists began to take note of "how is it changing," and "why is it changing," not just "how does it work?" The next sort of step in that process was "what are the consequences of these changes," not just to the ecosystems but to the people who depend on them, and finally, "how can we do a better job of managing activities that are causing the changes, or of mitigating the changes that are underway?" And so, over the thirty years that I’ve been a practicing scientist, there has been a real revolution in the nature of the questions that ecologists have been asking of the world, driven in part by larger-scale changes that they were observing.

As part of this revolution, she helped propose Sustainable Biosphere Initiative. I hope that at NOAA she can start to implement some of these ideas. The oceans, in particular, are under a double assault by climate change and overfishing. She writes:

Fisheries peaked in the mid 80’s and have been on the decline since then. This represents, in part, the sequential depletion of one fishery after another, after another. We also have data suggesting that 90% of all the big fish of the ocean are gone. The huge tuna, sharks, swordfish, marlin, and other icons of the sea have been very significantly depleted primarily by industrial-scale fishing over the last couple of decades.

There are major changes underway in oceans. In addition to that, more and more ocean ecosystems are undergoing very rapid, abrupt change. They are complex, nonlinear systems that are characterized by tipping-points, and we’re seeing very rapid changes, loss of resilience in these systems, loss of ability to cope with changes, and in fact very radical change as a result.

When I read things like this, I wonder what I should be doing. I’m sure many of you have faced these questions too.

Posted at December 24, 2008 2:26 AM UTC

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Re: Science and the Environment

Scientists have to lift the fog. It’s for others to build the brakes and apply them. We need a Ministry/Department of Truth, not to generate spin (as in “1984”), but to oppose it by conducting open vigorous well-funded mathematically literate investigations of the facts, backed by substantial powers of investigation and cross examination. Our responses to the looming energy crisis have been: The Hydrogen Economy, Biofuels and the Iraq war. The last is out of scope, but the first two wouldn’t have survived vigorous investigation. We’re down to our last few rolls of the dice on this. I urge everybody to see what can be done without the “well funded” bit, by looking at Sustainable Energy — Without the Hot Air, written by Prof David MacKay, head of the Inference Group in the Physics dept at Cambridge Uni. Yes we badly need well respected mathematically literate people to lead our society in thinking clearly about what will and won’t work.

Posted by: Robert Smart on December 24, 2008 5:02 AM | Permalink | Reply to this

Re: Science and the Environment

I agree: that looks like a great book. You can buy a paper copy, download it for free, or, if you don’t want to read the whole thing, download a 10-page synopsis (which I just read).

I see that the author, David MacKay, was also the inventor of the wonderful Dasher.

Posted by: Tom Leinster on December 24, 2008 1:34 PM | Permalink | Reply to this

Re: Science and the Environment

Thanks for the helpful comment, Robert!

You wrote:

Yes we badly need well respected mathematically literate people to lead our society in thinking clearly about what will and won’t work.

I guess that’s something I can imagine doing; I’ve already tried my hand at it, but only as a kind of hobby.

There seem to be two aspects to this: thinking clearly, and explaining things clearly in some forum that lots of people notice. They’re sort of complementary. I can imagine people who are at the cutting edge of figuring things out; these people should be publishing in refereed journals, so their ideas get criticized by other experts. I can also imagine people who take information that’s already been agreed on by a consensus of scientists, and try to pass it on to large numbers of people. I guess there’s a continuum, and one has to decide where one wants to sit in this continuum.

Of course this isn’t true only in environmental issues. In the math world, for example, we have people like Andrew Wiles who sit in their attic proving Fermat’s Last Theorem, and people like Simon Singh, who wrote a best-seller about what Wiles did. Very few people can successfully occupy both ends of this spectrum. In projects like This Week’s Finds and this blog I’m trying to stake out some sort of middle ground. You could call it ‘popularization, but only to a highly erudite crowd’. Maybe that’s what comes naturally to me.

Posted by: John Baez on December 26, 2008 3:37 AM | Permalink | Reply to this

Re: Science and the Environment

Here is a new report by an Engineer’s society for the british parliament on the expected tasks.


Posted by: Thomas on February 22, 2009 8:47 AM | Permalink | Reply to this

Re: Science and the Environment

John Baez:

I’ve no idea why you’re impressed by Holdren. People conveniently forget that Holdren was one of two people (the other being perennial doomster Paul Erlich) who bet Julian Simon concerning supposed resource depletion in 1980 (Holdren and Erlich bet that five chosen metals would rise in price while Simon argued the reverse). See the Wikipedia article for more.

Result: Holdren and Erlich lost. All five metals declined in price. Practically all metal ores declined in price.

That said, Holdren’s Powerpoint presentation was a compendium of anti-science, being composed of bad data, bad modeling, reversal of cause-and-effect and reams and reams of bad statistics combined with apocalyptic hysteria.

For example, his chart of sea surface temperature and cyclone power makes no mention of the fact that before the satellite era, hurricanes and tropical storm counts were undercounted. During the satellite era, despite rising sea level temperatures, the supposed relationship breaks down. (I’d post the links but for some reason the blog thinks the links are malformed)

Its embarrassing to watch Holdren being presented as some great scientist when his actual record is one of an environmental activist with a PhD making a big noise.

I’d post links to the above but it seems that your blog is averse to citations.

Posted by: John A on December 25, 2008 12:27 AM | Permalink | Reply to this

Re: Science and the Environment

John A: I hope that you do give citations, especially to scientific papers. If the blog software doesn't like your links, then just type in the URIs as text. I'll be happy to repost them in the proper format if I can; otherwise, we all know how to cut and paste.

Posted by: Toby Bartels on December 25, 2008 1:59 AM | Permalink | Reply to this

Re: Science and the Environment

I’m not mainly interested in debating the case for global warming and its effects here; I’m convinced there’s a problem and I’m mainly asking what I should do about it.

That said, it’s always good to get the facts straight — so bring on the references!

There are some annoying features to this blog, because it uses MATHML: for example, you can’t use

⟨A HREF =

It needs to be lowercase:

⟨a href =

But I’ll be glad to fix anything, and as a moderator it’s easier for me than for Toby.

Posted by: John Baez on December 25, 2008 3:32 AM | Permalink | Reply to this

Re: Science and the Environment

Actually John, you are the only logical guy I know who seems to buy into this global warming stuff. It would be interesting for me to understand why.

All the references I have seen make the same mistakes over and over, ones that are instantly clear to a mathematician.

They rely on consensus arguments (“The U.N says it, it must be so!”). They rely on anecdotal data (“Kilimanjaro is melting!” “It was hot last summer in Cameroon!” “There were hurricanes!”). They rely on computer models that are unspecified, or that seem over-fitted. They do not make short-term testable predictions (why trust these guys?). They do not define terms (“temperature of the earth in 2007”). They conflate tautological statements (“man affects climate”) with substantive ones (“man causes x degrees of warming per year”), and then with economic ones (“so we should change our behavior”). They rely on obvious rhetorical tricks (“I’m a nice guy, so I’m right”). They massage data in opaque and complicated ways before reporting.

And so on.

Most of the people making these arguments are not, shall we say, the sharpest tools in the shed. But you’re bright and knowledgeable, and more important you seem logical. Can you point to any specific references that persuaded you man-made global warming is a serious problem?

Posted by: man from mars on December 25, 2008 10:58 AM | Permalink | Reply to this

Re: Science and the Environment

‘Man from Mars’ wrote:

Actually John, you are the only logical guy I know who seems to buy into this global warming stuff.

I’m flattered!

As I already said, I’m not interested in discussing here the evidence that human-caused global warming is a serious problem. This blog entry is about something else, and so far only Robert Smart has replied to my concerns. If you like, you can read my thoughts on this subject from 2003 to now by looking at my diary. But even those weren’t designed to persuade ‘climate change skeptics’.

Posted by: John Baez on December 26, 2008 3:16 AM | Permalink | Reply to this

Re: Science and the Environment

I’ll just comment that I think that regarding anthropogenic global warming, I think almost everyone is asking the wrong question. They ask “What’s the likelihood of AGW happening as a purely scientific question?” whereas I’m inclined to say the question is “What’s the likelihood that AGW as something significantly affecting human beings is definitely not happening?” The first question wants a high probability that, in my very limited knowledge and using the experience of experts with more field knowledge, AGW doesn’t (maybe only “yet”) have compared to most science. (As an example of a “purely” scientific question, consider research into understanding the detailed physical cause of friction: current theories and more importantly ease of engineering experiments mean the answer to this question has no practical impact.) For the second question I think a relatively low probability (which is what would lead a decision-theoretist to take action) seems to be warranted by the evidence and experts.

FWIW, my bayesian probability that human-significant AGW is happening is about 20-25 per cent, but my bayesian probability that it’s definitely not happening is about 5 per cent. So I guess you could say that I don’t “buy into” (in your phraseology) AGW as a proven scientific theory, but do “buy into” actions to reduce extravagant energy usage, high levels of deforestation, etc. (To state the obvious, a theory can be not proven simply because the overpowering convincing experiments are not yet possible.)

As for John’s original question of “What can I do”, I’m still struggling with the fact that my relatively low-consumption lifestyle gets blown away by flights to conferences during the year.

Posted by: bane on December 29, 2008 10:35 AM | Permalink | Reply to this

Re: Science and the Environment

Some of these posts are really starting to weird me out. Can you hear yourselves, oh ye gods of the universe?

The challenge here is to share information in an unbiased, apolitical, non-patriarchal manner, and not like demagogue elitists. Do not soil the purity of science by using it to manipulate others. Share facts simply because they are facts, not because they confirm (or refute) your politics.

Bane got it right. Instead of leading by credentials, lead by self-evaluation and personal example.

Posted by: Rose on December 29, 2008 3:02 PM | Permalink | Reply to this

Re: Science and the Environment

I’m not sure if the last paragraph is a reference to me or there’s someone else. In case it is, what wasn’t what I was getting at. Most of the “stuff” about AGW is not observations (“facts”) but various interpretations, models and extrapolations from this data which aren’t yet either conclusively validated or refuted by experiment. My point was that a lot of people implicitly say these should be judged according to the standards of a purely scientific question, whereas I think they ought to be judged decision-theoretically. (People ought to be aware that’s what the standards they should be applying.)

The argument from authority is complicated: obviously people aren’t correct inherently because of their academic position, but I’m much more interested in the opinion of a climatologist who’s got his fingers dirty installing sensors and knows all the weird phenomena that occurs in them than in, say, a computer scientist who looks at the data and says “this bit’s incongruous” and draws extensive conclusions from that. (I’m a computer scientist, so this is pointing out that real training and experience in the subject is generally important, not snobbery.) There’s no way just “sharing information” is going to be enough, whether you believe actions contributing to AGW must be curtailed or you believe those trying to do the curtailing must be stopped. What is important to me is that I’ve seen too many non-AGW proponents arguing that global warming is far from scientifically established, when that’s the wrong yardstick. (And I want to hear these arguments against that yardstick: I asked one economist who was arguing AGW was scientifically unproven and hence ignored about his view decision theoretically and his response was “It’s too big to do”, which is a real cop-out.)

The “humility” in the last sentence was merely me trying to belatedly respond to John’s original question.

Posted by: bane on December 29, 2008 5:19 PM | Permalink | Reply to this

Re: Science and the Environment

Rose said:

The challenge here is to share information in an unbiased, apolitical, non-patriarchal manner, and not like demagogue elitists. Do not soil the purity of science by using it to manipulate others. Share facts simply because they are facts, not because they confirm (or refute) your politics.

Patriarchal demagogue elitists? Manipulation? Did I miss something exciting?

As far as I can tell, people here are just talking. I don’t see anyone here manipulating anyone else. I don’t even see how they could, particularly, unless behind the scenes.

Posted by: Todd Trimble on December 29, 2008 8:31 PM | Permalink | Reply to this

Re: Science and the Environment

Forgive me, I didn’t mean to come off sounding so self-righteous.

I’m one of those Hispanic females with approximately 2.8 children despite my 16+ years of education, BPA ingestion, and perhaps some addictive, euphoric contraceptive surreptitiously placed in my water supply. It was hard to read some of you fellows trying to figure out a way to fix me. :)

Posted by: Rose on December 30, 2008 7:02 PM | Permalink | Reply to this

Re: Science and the Environment

Actually, you've got a good point. It's all well and good to say ‘What can we do for these people?’, but you won't get very far if you don't talk to them, and ultimately if they aren't the ones leading the effort.

(I'm an educated person, male for reproductive purposes, with no children, surrounded by educated women and other educated people, usually with 0–2 children, 0–3 at the outside, in a family. So uneducated women and large families are ‘them’ to me.)

Posted by: Toby Bartels on December 31, 2008 5:32 PM | Permalink | Reply to this

Re: Science and the Environment


My first comment (Dec. 30th post) was genuine, for indeed I am not righteous in these matters. I’m one child “over-quota”, for which I do not apologize. I claim to be a conservationist, yet because I am tenured in an overcrowded urban area I commute 600 miles a week. I have grass in my front yard. I occasionally eat animal products. I could go on, but you get the point. I am not ecologically virtuous, so who the heck should listen to my personal analysis of the data?

My second comment was satirical. I don’t know… a group of men trying to solve overpopulation by convincing women to stop having babies, as though these women do so in a vacuum, just strikes me as comedy. :)

But my initial comments (Dec. 29th post), though perhaps poorly stated were sincere.

Toby wrote:

you won’t get very far if you don’t talk to them, and ultimately if they aren’t the ones leading the effort.

Yes, you get me Toby. Who is the audience? The general public, they are the ones who will affect change. Talk with the masses, not at them. And be very careful when you do, for simple people recognize condescension and hypocrisy better than most. (A good reason to court simplicity in my life, avoid complexity, and just stop being so full of myself!)

There is much discussion here about educating women for the purpose of population reduction. Education may be a primary causality, but childbearing variations may arise from a secondary causality. Some reasons cited in published works for decreased fertility among educated women are:

* opens up greater opportunities for women that often conflict with repeated child-bearing

* may cause women to be less likely to prefer sons over daughters (large families produce more sons to provide financial support)

* causes women to have higher aspirations for their children, combined with lower expectations of them in terms of labor services

While not exhaustive, these three reasons are commonly associated with increased income opportunities that accompany female education. Thus the secondary causality may be fiscal, not academic, which may ultimately backfire on the environment.

I propose that educating BOTH genders is the solution, but not necessarily emphasizing the acquisition of wealth. (I was never a better conservationist than when I was poor, so I buy into this idea of reasonably limiting economic growth. I suppose, okay, yes… we can start with my own economic growth.)

Rather, educate the individual to independently analyze the data, or at least give them the confidence to question the analysis of others, so they can draw their own conclusions about securing the future well-being of their environment.

(I encouraged my students this way during the recent presidential election. A peer questioned, “What if after analyzing the candidates your students arrive at erroneous conclusions?” “Oh, you mean conclusions different than my OWN?” -He missed the whole point.)

When this is accomplished, when people are encouraged to reason independently to any significant degree, the public will be able to question and debate inaccurate interpretations, models and extrapolations of the data. One problem (to some), they will be more apt to self-govern, and thus harder to control.

Am I too simplistic? Can people be educated to reason? I believe they can. Although, I am troubled by what I am watching today in Gaza…

John wrote:

Another idea: one conference per year, lasting a month, where you hang out with all your favorite colleagues in a gorgeous location. Only a few talks, tons of spare time. It sounds indulgent

Only indulgent if it is paid for by government bail-out funds, brother. :)

By the way, I’m really enjoying David MacKay’s book, Sustainable Energy — Without the Hot Air.

Posted by: Rose on January 4, 2009 10:57 PM | Permalink | Reply to this

Re: Science and the Environment

I was going to let this non-categorical thread end, but…

Rose wrote “the public will be able to question and debate inaccurate interpretations, models and extrapolations of the data. One problem (to some), they will be more apt to self-govern, and thus harder to control.” There seems to be this ideal of an informed electorate who will understand and debate highly complex issues, particularly models. A genuine question: does anyone actually believe this will ever happen?

I don’t look at complex climatological stuff beyond a brief overview, because I don’t have the time to devote to really understanding the issues to a level where I can genuinely spot what are real problems and what are phenomena well known to those actively working in the field but which aren’t obvious to a casual calculation/etc. (I try to avoid “knowing just enough to be dangerous” by trying to either just follow the tide of expert opinion or by analysing things in real detail – which I have time to do for only a few things.) Regardless of the depth of the literature of people like Tom Payne, in almost the entirety of the past almost all of the time the electorate/people were strongly involved in government it was on the basis of very simple issues which were more “personal values”-based than theory based. (“No taxation without representation!”, etc.) I would say I’m “easier to control” more because I just have too many other things that take my time than because I don’t have the capacity to think independently.

In contrast, people like Bill Gates or George Soros who’ve acted pretty much non-democratically in their funding of their view of “charitable priorities” have had more impact than an informed electorate. (They happen to be men, but I regard their mental characteristics as more germane to their actions than their biological gender.)

Posted by: bane on January 4, 2009 11:53 PM | Permalink | Reply to this

High School perspective; Re: Science and the Environment

Prolific author Harlan Ellison gets annoyed when someone says: “I’m entitled to my opinion.”

“No!” he snaps, “You’re entitled to an INFORMED opinion.”

I feel that I have one, having actually taught Ecology at the University of Massachusetts for a semester somewhere in 1973-1975.

Recently, I taught a semester of high schoolers Evolution and Ecology. They were, about half of them, at least half-trying.

But what do you do, when half of them are Creationists (because their parents are) and write things on homework assignments such as: “What you said in class in ‘The 20 Greatest Ideas of Science’ about Conservation of Energy. Yes. I think that energy should be conserved, because of global warming and stuff.”

The public in the USA is hideously, mind-bogglingly misinformed about basic Science, let alone complicated emergent phenomena.

What they don’t know (ignorance) is, in principal, curable, via education. What they THINK that they know, which is wrong – that’s a much harder problem.

You have no idea unless you take questions at public lectures, broadcasts, or classrooms.

I’m glad that we have actual scientists in cabinet level positions as of 2 weeks from now, whatever positions they may have.

I’m also glad to have John Baez quoting from Yaneer Bar-Yam at NECSI. He and his father are both genuine much peer-reviewed Physicists, as well as thier Complexity involvement. This interest is indirectly connected with why I asked John Baez to be a keynote speaker, or at least a speaker in the Physical Sciences track I chaired at the last NECSI International Conference on Complex Systems.

As to when the 2009 one is, or if it slips to 2010, seems to depend on the global depression, and how that affects travel budgets of academics.

Posted by: Jonathan Vos Post on January 5, 2009 7:18 AM | Permalink | Reply to this

Re: Science and the Environment

Bane wrote:

As for John’s original question of “What can I do”, I’m still struggling with the fact that my relatively low-consumption lifestyle gets blown away by flights to conferences during the year.

Me too. I need to change my lifestyle. I think this means I need to say ‘no’ to lots of people offering to fly me here and there. I would find it infinitely easier to fly less if I were the one paying for the trips: my miserly nature would kick in and help me out. But saying no to free trips — that takes real willpower.

(Another option is to say I’ll only fly somewhere if the folks inviting me pay for a carbon offset. Opinions are divided on the merits of these carbon offsets. However, a demand like this might succeed in getting people to stop inviting me to give talks.)

However, while this is a very tough issue and very important, I won’t be satisfied ‘leading by example’, staying home as a virtuous low-carbon hermit. I want to do something helpful that uses my particular abilities as a scientist. But I’m not sure what — that’s what I’m trying to figure out.

Posted by: John Baez on December 30, 2008 2:04 AM | Permalink | Reply to this

Re: Science and the Environment

As I’m pseudonymous, I ought to mention that I consider myself a mathematician working as a computer scientist/engineer in computer vision and robotics. We have the technology now to render the formal aspects of conferences (giving talks/posters, asking questions of the speaker) possible remotely. We could probably equip people with robotic surrogates (there’ve been such proposals :-) )they could send if some other people would still want to attend the conference directly. The problem that I have is that the other important things that happen at conferences, like talking to people in-depth, building the network of people you know, etc, don’t seem to be things that technology can work around. So thinking about this is in my work area, but all my thinking about it hasn’t generated any practical ideas. (I think about this a lot since both AGW and peak-oil don’t seem to be in the realm of “definitely not happening” (ie, it’s worth taking actions in case they’re happening), I just haven’t had any interesting, practical ideas.)

Posted by: bane on December 30, 2008 5:21 PM | Permalink | Reply to this

Re: Science and the Environment

Bane wrote:

The problem that I have is that the other important things that happen at conferences, like talking to people in-depth, building the network of people you know, etc, don’t seem to be things that technology can work around. So thinking about this is in my work area, but all my thinking about it hasn’t generated any practical ideas.

I’m glad you’re thinking about this! It’s a sad fact that having a successful career in business or academia seems to require lots of air travel even in this age of electronic communication. Even a little air travel completely undoes everything else one might do to reduce ones CO2 emissions.

I’ve imagined conference centers with ‘virtual restaurants’. They’d have tables equipped with flat-screen TVs and webcams that could convey the illusion of having dinner with people in other cities. If there was a chain of such restaurants with a branch in each major city, one could have dinner and talk with colleagues without leaving town. And if the menu was the same at each branch, you could even discuss what to order!

This blog, and the nnLab, are other ways of attacking the problem. In terms of actual scientific content, I probably get more out of online discussions than conferences. However, attendance at conferences seems to be essential to build a flourishing academic career. The way this works has got to change.

Another idea: one conference per year, lasting a month, where you hang out with all your favorite colleagues in a gorgeous location. Only a few talks, tons of spare time. It sounds indulgent, but it could be more effective and less damaging to the environment than jetting around to short conferences packed with talks!

Posted by: John Baez on December 30, 2008 6:44 PM | Permalink | Reply to this

Re: Science and the Environment

I’ve always been a little bothered about carbon footprint calculations with respect to air travel. If you divide the carbon emissions due to a flight I take to get to a conference by the number of passengers, then my share will be quite a lot of carbon. But suppose I drive instead. The effect on the carbon emissions of the plane flight - which will still take place without me on board - is negligible. But now there are the added emissions from my car. It’s not clear that just staying home is better either, since I drive more at home than I do when I’m at a conference. (Since I live in North America, trains usually aren’t a feasible travel option, except to get to and from airports.)

I don’t mean to try to weaken the argument that less air travel would be better for the environment. But I think the carbon footprint is a problematic number on which to base decisions.

(I considered writing this comment some time ago, and had essentially defaulted to not writing it. But this week I’m at a conference which took two flights and a two-hour shuttle ride to get to, so maybe I’m feeling some pangs of environmental guilt.)

Posted by: Mark Meckes on January 13, 2009 5:57 AM | Permalink | Reply to this

Re: Science and the Environment

While you may not affect the emissions of the particular flight significantly, your presence on the flight tells the airline that they can sell more seats (than if you did not fly), so in the future you are contributing to larger planes, or more frequent flights.

This isn’t to disagree with your whole post; it is more a reminder that purchases should be examine both for their immediate consequences and their economic message.

Posted by: gang on January 13, 2009 7:32 AM | Permalink | Reply to this

Re: Science and the Environment

I considered bringing up that issue myself, but decided to avoid introducing that can of worms into my earlier post. The issue as I see it is that my individual presence (or lack thereof) on a particular flight also has a negligible effect in that respect; however, if I join many other people in consistently avoiding unnecessary flights then the effect is much larger. This leads quickly to questions of effectiveness and ethics that I don’t want to get into here.

Posted by: Mark Meckes on January 13, 2009 2:44 PM | Permalink | Reply to this

Re: Science and the Environment

There’s also the issue of where and how you live. People living in Europe tend to have many more people living in denser cities with better public transport, so that air travel has at least the effect of their general daily activities. I mostly walk to work and take train journeys every so often, so following David McKay’s numbers air travel, “stuff” and eating meat are probably my biggest energy usages. (I’m at least as concerned about total energy availability as by climate change.)

(This isn’t getting at you personally, just pointing things out. America, and to a lesser extent Britain, organised public infrastructure building for the car, and the populace now face harder times using public transport effectively.)

Posted by: bane on January 13, 2009 9:51 AM | Permalink | Reply to this

Unaticipated effects of Car Culture and Suburbs; Re: Science and the Environment

“People living in Europe tend to have many more people living in denser cities with better public transport.”

We never voted on this, but after World War II the United States underwent a density/transport phase change.

(1) Suburbs were reinvented. The oldest were anomalies, such as Brooklyn Heights, which began in New Amsterdam as a place across the East River for the very wealthy to build second homes. The new suburbs were explicitly planned and mass produced, Levittown being the beta-test.

(2) America married the automobile. It became inevitable that Eisenhower and Al Gore’s father pushed through national highways, under the guise of National Security.

The unintended consequences, it seems to me, included:

(A) Decay of the Extended Family, replaced by the nuclear family. The default shifted away from grandparents, parents, children, in the same home, to the parents and kids driving back from their own homes on holidays to visit the grandparents.

(B) Diversion of transportation infrastructure financing from public transport in cities to the new suburb/exurb model.

(C) Beginning of schism in public schools, into elite schools with goof facilities and highly trained teachers, versus inner city schools in crumbling facilities with less expert teachers, associated with “white flight.”

The phase change was dramatic in in dependence on cheap oil. It now seems unsustainable. The ecological issues raised include the asphalting of America, and the destruction of farmland for new real estate development.

These second-order effects may have been predictable. Nobody seems to have predicted third-order effects, such as drive in theatres, drive through restaurants (a fast food/transport amalgam), motels, the minimall (arguable “Hen’s Teeth Square in Altadena, California was the first) changes in teenagers’ sexual opportunities afforded by cars and back seats.

I’m trying to say this objectively. Although I grew up in Brooklyn Heights, enjoying a culturally enriched scene adjacent to New York City’s Broadway and museums and the like, and have lived in small towns and suburbs (such as Amherst, Massachusetts; Kent, Washington; Altadena, California), I can be passionate about cities and suburbs alike (and have no experience in rural life).

Each phase has its advantages and disadvantages. But Car Culture may have been a mistake, and one very painful from which to extract ourselves. It would be intolerable for the whole world to attempt emulation of American Car Culture, as seems to have started. Not enough material resources; too much pollution. We are trapped in a local minimum, and now consider moving to a global minimum on the other side of a potential barrier.

Posted by: Jonathan Vos Post on January 13, 2009 5:40 PM | Permalink | Reply to this

Re: Science and the Environment

One thing you could do would be to come up with a method for reducing human fertility that is either undetectable or else is politically acceptable.

So far the methods which have successfully evaded detection have not reduced fertility.

One method was tried in China which had the desired effect but which has only been politically acceptable in the short term. The best alternative which is still being tried is to educate women.

In case you don’t feel qualified to tackle that problem there is an alternative which might have more appeal to a mathematical physicist. Namely to come up with a proper theory of economics. A starting point would be a clear concept of wealth and how and where it is created. For example, you would not describe putting a pipe in the ground and watching oil spurt out as oil production. The physical concept of energy should have a role as should information and entropy.

Happy Christmas!

Posted by: Bruce Westbury on December 26, 2008 1:28 PM | Permalink | Reply to this

Re: Science and the Environment

One thing you could do would be to come up with a method for reducing human fertility that is either undetectable or else is politically acceptable.

Imposing human fertility secretly from above is about as palatable (and moral) to me as Soylent Green – another solution to the problem of overpopulation and depleted resources. Yeesh.

Posted by: Todd Trimble on December 26, 2008 3:42 PM | Permalink | Reply to this

Re: Science and the Environment

You might also be interested to read “A modest proposal” written by Jonathan Swift and published anonymously in 1729.

I have just heard about this from listening to Melvyn Bragg on BBC Radio 4.

Posted by: Bruce Westbury on January 30, 2009 7:56 AM | Permalink | Reply to this

Re: Science and the Environment

Bruce Westbury wrote:

One thing you could do would be to come up with a method for reducing human fertility that is either undetectable or else is politically acceptable.

I want to save the planet — but I’m not enough of a mad scientist to think the morally correct way to go about this would be to invent something that would secretly, subtly reduce human fertility.

Still, it’s fun to think about how I would go about it, if I were a mad scientist.

I know! I’d create a cheap kind of plastic — say, something that’s great for making bottles — that would catch on and get widely used. But, it would also subtly disrupt the human endocrine system, reducing fertility! Nyeh-heh-heh…

Oh - whoops! It’s already been done!

Or maybe not. But anyway, it’s not an original idea.

Todd wrote:

Yeesh.

Yeah, okay. Back to the drawing board.

Actually, I think the best method for reducing the birth rate is educating women. Within the US, for example…

… a women’s educational level is the best predictor of how many children she will have, according to a new study from the National Center for Health Statistics, Centers for Disease Control and Prevention.

Educational attainment is a very critical factor in accounting for lifetime fertility differentials. Women with 1 or more years of college have sharply lower lifetime fertility than less educated women, regardless of race or Hispanic origin. Women with college degrees can be expected to complete their childbearing with 1.6-2.0 children each; 1.7 for non-Hispanic white, 1.6 for non-Hispanic black, and 2.0 for Hispanic women. For women with less education the total expected number of children are: 3.2 children for those with 0-8 years of education; 2.3 children for those with 9-11 years of education and 2.7 for high school graduates.

Among unmarried mothers age 25 and older only nine percent had college degrees; about a third has less than a high school education. Birth rates for college-educated unmarried women are substantially below the rates for less-educated unmarried women.

And, there seems to be a correlation worldwide:

Lots of people have thought about this issue. And one great thing about educating women, as compared with most other ways of tackling the problem of overpopulation, is that the objections to it are all pretty unconvincing (at least to me).

Posted by: John Baez on December 27, 2008 3:12 AM | Permalink | Reply to this

Re: Science and the Environment

there seems to be a correlation…

For intervention, however, you need to know about causality, not just correlation. What aspects of educational attainment, or which of its correlated variables, might be causally related to birth rates?

You see the point. It might be rather the societal attitude which promotes education for women than the education per se which brings about changes in fertility rate.

Posted by: David Corfield on December 27, 2008 12:39 PM | Permalink | Reply to this

Re: Science and the Environment

I’m not sure you need to know that education is definitely causal wrt fertility to intervene, particularly since few would claim any bad effects from increased female education, you might just not intervene optimally (or possibly without any effect whatsoever) if you modify correlated variables that you aren’t sure are causal variables.

(As an example, I’m currently struggling with a 3G USB modem. I think I get fewer dropped connections if I stick it out the window. I don’t understand that being outside definitely causes fewer problems, and haven’t even done systematic experiments to avoid “stopping experiment criteria” problems, but I’m currently in the habit of dangling it out the window. Obviously there’s a point at which this behaviour could descend into cargo-cult science, but I don’t think I’m there yet.)

Posted by: bane on December 29, 2008 10:57 AM | Permalink | Reply to this

Re: Science and the Environment

Bane wrote:

I’m not sure you need to know that education is definitely causal wrt fertility to intervene, particularly since few would claim any bad effects from increased female education…

Actually I believe there are significant numbers of people who claim bad effects from increased female education. But they’re people you and I don’t talk to, and don’t particularly respect. Like, say, the Taliban, or certain other Islamic fundamentalists, or a lot of men in places where educating women isn’t the norm.

Anyway, I agree with your real point: since I regard increased education of women as a good in itself, I don’t think it’s bad to push for it, even if it turns out not to save us from overpopulation.

Still: if something else is responsible for people having fewer kids, it would be good to know what it is.

Posted by: John Baez on December 30, 2008 2:19 AM | Permalink | Reply to this

What Hath Gaylord Nelson Wrought? Re: Science and the Environment

The two politically acceptable trends that correlate best with reduced fertility are female literacy, and urbanization.

On the first Earth Day, 22 April 1970, I helped Wavy Gravy and other activists build a (temporary) dome on the Caltech campus, and I tried to explain that all their eco-utopian visions would fail unless the population explosion was addressed.

I gave an example of a politically unacceptable solution. Dispense an addictive, euphoric contraceptive globally, using local crime syndicates as distributors, and using the cash flow to manufacture the stuff and pay for the R and D that invented it.

Then dispense the antidote to the contraceptive component, but only to couples that could pass a parenting exam. I mean why do we need to pass a written and on-the-ground driving test to legally drive a car, and we let any fools get each other pregnant?

The activists were not impressed. And the population explosion is, as Herman Kahn first pointed out circa 1960, a logistic curve and not an exponential.

Posted by: Jonathan Vos Post on December 27, 2008 8:40 PM | Permalink | Reply to this

Re: Science and the Environment

David wrote:

For intervention, however, you need to know about causality, not just correlation. What aspects of educational attainment, or which of its correlated variables, might be causally related to birth rates?

I don’t know much about this subject, which is why I gave this link with some references. A quote:

Education has been found to delay entry into marriage, to favour a normative orientation towards smaller families and to increase awareness, access and acceptability of contraception. However, in the poorest and least literate societies small improvements in female education initially increase fertility, by improving maternal health and reducing the duration of breast-feeding and post partum sexual abstinence. But once the process of child bearing becomes at least partially subject to conscious planning, the relationship between female education and fertility is bound to be unequivocally inverse.

To learn more we might start with these:

  • Susan H. Cochrane, Fertility and Education: What Do We Really Know?, Baltimore, Maryland: Johns Hopkins University Press, 1979.
  • United Nations, Fertility Behaviour in the Context of Development: Evidence from the World Fertility Survey, Population Studies, No.100 ST/ESA/SERA/100. Sales No. E.86.XII.5, 1987.

I hope this is just the tip of a huge iceberg of research. After all, the World Bank claims to be making education of women a priority, and they’re acting like the causal link to decreased fertility is a known fact — though that’s just one of their reasons for pushing for the education of women. They list a bunch of reasons, and here’s the first:

Reducing women’s fertility rates. Women with formal education are much more likely to use reliable family planning methods, delay marriage and childbearing, and have fewer and healthier babies than women with no formal education. It is estimated that one year of female schooling reduces fertility by 10 percent. The effect is particularly pronounced for secondary schooling.

I’m not claiming the World Bank gets everything right, of course! I just hope such remarks mean that with a little digging one could find a lot of information on this incredibly important topic.

Posted by: John Baez on December 27, 2008 11:52 PM | Permalink | Reply to this

Re: Science and the Environment

Jonathan wrote:

And the population explosion is, as Herman Kahn first pointed out circa 1960, a logistic curve and not an exponential.

Birth rates are dropping wherever people become wealthy and educated. Unfortunately this may not be good enough. There are incredibly divergent opinions on how many people the Earth can support over a long time period, but it’s possible that in a world with today’s population, but with everyone living like Europeans or Americans, we’ll completely trash the planet unless we achieve dramatic increases in efficiency.

Recently I bumped into this::

A quote:

The Ehrlich equation, I = PAT, says simply that the impact (I) of human activity on the planet is the product of three factors: the size of the population (P), its level of affluence (A) expressed as income per person, and a technology factor (T), which is a measure of the impact on the planet associated with each dollar we spend.

Take climate change, for example. The global population is just under 7 billion and the average level of affluence is around $8000 per person. The T factor is just over 0.5 tonnes of carbon dioxide per thousand dollars of GDP - in other words, every $1000 worth of goods and services produced using today’s technology releases 0.5 tonnes of CO2 into the atmosphere. So today’s global CO2 emissions work out at 7 billion × 8 × 0.5 = 28 billion tonnes per year.

The Intergovernmental Panel on Climate Change (IPCC) has stated that to stabilise greenhouse gas levels in the atmosphere at a reasonably safe 450 parts per million, we need to reduce annual global CO2 emissions to less than 5 billion tonnes by 2050. With a global population of 9 billion thought inevitable by the middle of this century, that works out at an average carbon footprint of less than 0.6 tonnes per person - considerably lower than in India today. The conventional view is that we will achieve this by increasing energy efficiency and developing green technology without economic growth taking a serious hit. Can this really work?

With today’s global income, achieving the necessary carbon footprint would mean getting the T factor for CO2 down to 0.1 tonnes of CO2 per thousand US dollars - a fivefold improvement. While that is no walk in the park, it is probably doable with state-of-the-art technology and a robust policy commitment. There is one big thing missing from this picture, however: economic growth. Factor it in, and the idea that technological ingenuity can save us from climate disaster looks an awful lot more challenging.

First, let us suppose that the world economy carries on as usual. GDP per capita will grow at a steady 2 or 3 per cent per year in developed countries, while the rest of the world tries to catch up - China and India leaping ahead at 5 to 10 per cent per year, at least for a while, with Africa languishing in the doldrums for decades to come. In this (deeply inequitable) world, to meet the IPCC target we would have to push the carbon content of consumption down to less than 0.03 tonnes for every thousand US dollars spent - a daunting 11-fold reduction on the current western European average.

Now, let’s suppose we are serious about eradicating global poverty. Imagine a world whose 9 billion people can all aspire to a level of income compatible with a 2.5 per cent growth in European income between now and 2050. In this scenario, the carbon content of economic output must be reduced to just 2 per cent of the best currently achieved anywhere in the European Union.

The potential for technological improvements, renewable energy, carbon sequestration and, ultimately perhaps, a hydrogen-based economy has not been exhausted. But what politicians will not admit is that we have no idea if such a radical transformation is even possible, or if so what it would look like. Where will the investment and resources come from? Where will the wastes and the emissions go? What might it feel like to live in a world with 10 times as much economic activity as we have today?

Instead, they bombard us with adverts cajoling us to insulate our homes, turn down our thermostats, drive a little less, walk a little more. The one piece of advice you will not see on a government list is “buy less stuff”. Buying an energy-efficient TV is to be applauded; not buying one at all is a crime against society. Agreeing reluctantly to advertising standards is the sign of a mature society; banning advertising altogether (even to children) is condemned as “culture jamming”. Consuming less may be the single biggest thing you can do to save carbon emissions, and yet no one dares to mention it. Because if we did, it would threaten economic growth, the very thing that is causing the problem in the first place.

I haven’t checked these figures, and given the unreliability of New Scientist, I really should. But if it takes anywhere near this amount of reduction in carbon footprint to avoid serious global warming, I think the world is bound to get a lot hotter before humans reach some sort of lifestyle that doesn’t continually degrade the environment. The human race will survive — I’m not worried about that. But many other species may not.

Whoops! I’m getting lured into talking about controversial issues here, which was not really the point of this blog entry! I was really just wanting some suggestions and advice about what mathematicians and physicists can do.

Posted by: John Baez on December 28, 2008 12:27 AM | Permalink | Reply to this

Re: Science and the Environment

I can’t make heads or tails of that purported “formula”.

But perhaps some basic figures will set the perspective. The US comprises about 5% of the world’s population. We consume 3.3 TW of power. The world as a whole currently consumes about 15 TW. Let’s not even contemplate the rest of the world catching up with US levels of profligacy. Even the most modest projections are for world power consumption to double to 30 TW by 2050.

That’s a heckuva lot of power.

As a physicist, you might want to think about ways to meet that demand (preferably ones which did not involve burning outrageously large amounts of coal).

Posted by: Jacques Distler on December 28, 2008 4:59 AM | Permalink | PGP Sig | Reply to this

Re: Science and the Environment

I can’t make heads or tails of that purported “formula”.

It simply defines T as the ratio of impact on the planet (as measured, apparently, in mass of CO2 or equivalent) to gross world product (as measured in money equivalent). Then it derives some conclusions from the assumption that, absent restructuring of the economy, this ratio will not shrink even in the face of technological improvements in energy efficiency. (In particular, it considers this ratio more important than the ratio of impact to population. Higher emissions in wealthier countries lend support to this approach.)

Posted by: Toby Bartels on December 28, 2008 8:38 AM | Permalink | Reply to this

Re: Science and the Environment

Suppressing population growth would only improve the situation somewhat. It would have to be coupled with massive worldwide cultural change. While I’m sitting here listening to a beautiful classical music composition performed by brilliant musicians and playing through my wonderfully engineered loudspeakers, I’m thinking how otherwise utterly stupid and thoughtlessly we behave as a species. For example, the cultivation of cows for the beef market is a huge greenhouse gas producer, is by far the most inefficient source of meat protein, and is a big motivator for the clearing of rain forests. Another example of stupidity: the large market for exotic animal parts for consumption, based on the belief that they have medicinal value or helps you get your rocks off, is a huge sickening threat to animal diversity on this world. Another example: mindless overfishing of the oceans. I could go on and on.

Posted by: Richard on January 2, 2009 4:22 AM | Permalink | Reply to this

Re: Science and the Environment

What to do?
John,
A. You have the rare skill of being able to communicate clearly, one of the most difficult and important of human talents. Also, as you have shown over and over, you have the ability to survey a wide array of interrelated abstractions, technologies and tools of exquisite complexity and then present a summary integrating seemingly disparate facets into a simplified overview that displays a new system that has never been perceived so clearly before.

B. As our knowledge about and ability to impact our surroundings increase, a growing metaproblem keeps rearing its intractable head; every time we fix something, more and more often we notice that we break something else. We are great at fixing the problem of the day, only to learn that we inevitably create chaos later on. Every day in our cultures, in our societies, in our governments, in our technologies, both locally and globally, we see this happening. In generally, we just don’t have the skill, or even the desire, to look at the bigger picture, to understand the broader system. It’s as if all our policies and interventions were implemented by incompetent teenagers (with my apologies to teenagers) whose only concern is instant results. They know all about the trees but don’t have a clue about how the forest works.

Examples? The ever-spreading implications of the latest economic meltdown, which every day continue to shock and surprise the experts expected to explain and fix it. The ever-changing solutions presented and then withdrawn for the energy crisis – you know what they are. Fixing the health system (patients, insurance, government, health care personnel, hospitals, drug companies); improving our educational system (from pre-school to professors). Then there is the dwindling water supply; the growing pollution problems; the long-term social and economic outcome of the lending crisis; the spread of the post-Detroit economy; the outcome of the Amazon.com trend; can the U.S. survive as a services-dominated economy embedded within the world economy, and on and on.

Looks like A applied to B is an excellent fit. Just presenting an accurate characterization of a problem would be a wonderful gift. Which problem? They are all huge! Too hard! Maybe so, but the trick is to pick a subsystem in one of these huge messes, a piece that you feel comfortable with, and use it as a pilot project to test your high-level problem defining/solving skills. Look at a short time-frame of just 2-3 years. Then spend a few days sketching out the essentials on the back an envelope. If you can’t find reliable data for this sketch, just make it up. It’s the forest that matters, not the trees. You are an expert at this kind of analysis; this is where you are uniquely qualified to contribute. This is the part that the politicians and specialists can’t do. After this little exercise, I predict the way for you to proceed will be clear.

Happy Holidays!

Posted by: Charlie C on December 26, 2008 1:44 PM | Permalink | Reply to this

Re: Science and the Environment

Charlie C wrote:

Just presenting an accurate characterization of a problem would be a wonderful gift. Which problem? They are all huge! Too hard! Maybe so, but the trick is to pick a subsystem in one of these huge messes, a piece that you feel comfortable with, and use it as a pilot project to test your high-level problem defining/solving skills. Look at a short time-frame of just 2-3 years. Then spend a few days sketching out the essentials on the back an envelope.

Thanks for this suggestion. Even before trying it, I can sense that this is the sort of project I would really enjoy. There are lot of problems facing us that are so big we tend to flip-flop between despair — “the problem is too big to solve!” — and wishful thinking — “it’s not really a problem at all”. I suspect these two extreme attitudes are flip sides of the same coin.

To break out of this dilemma, it might be good to chart out a few options of what we (the world) can do about these problems, and what could be the likely results. Of course nobody can tell for sure… but at the very least, it would help take these problems out of the realm of fantasy and nightmare, into the realm of rational discussion.

I may not be explaining this very clearly. A good example of what I mean is Pacala and Socolow’s paper on “stabilization wedges”:

They list 15 measures, each of which could reduce carbon emissions by 1 billion tons per year by 2057. Here’s an executive summary of what they claim:

  • If we adopt 12 of these measures, we could lower our carbon emissions from the current figure of 8 billion tons per year to 4 billion tons per year by 2057. This might mean 450 parts per million of CO2 in the atmosphere by this time, and a global temperature rise of 2° C (or 3.6° F). With this, we could still expect coastal flooding that affects millions of people per year. Cereal crop yields will tend to decrease in low latitudes. And, up to 30% of species might face the risk of extinction, with most coral reefs being bleached. But this is the “good” scenario!
  • If adopt only 8 of the measures, we could hold our carbon emissions constant at the current figure of 8 billion tons per year. This might mean 525 ppm of CO2 in the atmosphere, and a global temperature rise of 3° C (or 5.4° F). With this, we can expect the widespread death of coral reefs. We can also expect the bad consequences listed above, together with: 30% of coastal wetlands being lost, with most ecosystems becoming carbon sources as permafrost thaws and vegetation burns or rots.
  • If we adopt none of the measures, we can expect carbon emissions to double by 2057, to 16 billion tons per year. This might mean 800 ppm of CO2 in the atmosphere, and a global temperature rise of 5° C (or 9° F). With this, we can expect that more than 40% of species will face extinction. We can also expect the bad consequences listed above, and cereal crop yields decreasing in some mid- to high-latitude regions.

Here are the 15 “wedges”:

One can argue about everything in this paper — but that’s part of why it’s good. It provides a starting-point for quantitative discussions. It helps us get out of the panicky phase where the only two positions are “We’re doomed!” or “Everything will be okay.”

Posted by: John Baez on December 30, 2008 2:52 AM | Permalink | Reply to this

Re: Science and the Environment

Great! This looks like the kind of total system framework that could help guide discussion, analysis, and additional exploration very nicely. It tries to quantify the effects of various potential actions, it tries to indicate side effects and interrelationships among various actions, and it makes it easier to look for and add missing components. Also, it has the added benefit of keeping focus on relevant problems, solutions, and side-effects. Without a reminder like this, it is all too easy to spend time and effort orbiting some grain of sand with little prospect of achieving results with any significant impact. Thank you!

BTW, the link to

Stabilization wedges: solving the climate problem for the next 50 years using current technologies

returned a “Page not found” message at wiki.brown.edu. Browsing the wiki didn’t work either.

Posted by: Charlie C on December 30, 2008 3:44 PM | Permalink | Reply to this

Re: Science and the Environment

Charlie wrote:

BTW, the link to

Stabilization wedges: solving the climate problem for the next 50 years using current technologies

returned a “Page not found” message at wiki.brown.edu.

That link used to work, but no longer. I’ve changed it to a link that works now.

Unfortunately, Pacala and Socolow published their paper in Science, which has not made it freely available. So, I believe all free online versions of their paper break copyright law. So, links that work today may not work tomorrow.

Pacala and Socolow are involved with the Carbon Mitigation Initiative at Princeton. This organization has a webpage on the ‘stabilization wedge’ concept that includes a link to this free paper:

as well as a link to their Science article… which you can only access if you or your employer have a subscription to Science.

Posted by: John Baez on December 30, 2008 5:59 PM | Permalink | Reply to this

Re: Science and the Environment

I suppose this is mostly a rehashing of common knowledge, but I thought I’d contribute this link to an article of Jared Diamond: “What’s your consumption factor?”

A few quotes:
“The population especially of the developing world is growing, and some people remain fixated on this. They note that populations of countries like Kenya are growing rapidly, and they say that’s a big problem. Yes, it is a problem for Kenya’s more than 30 million people, but it’s not a burden on the whole world, because Kenyans consume so little. (Their relative per capita rate is 1.) A real problem for the world is that each of us 300 million Americans consumes as much as 32 Kenyans. With 10 times the population, the United States consumes 320 times more resources than Kenya does.”

“People in the third world are aware of this difference in per capita consumption, although most of them couldn’t specify that it’s by a factor of 32. When they believe their chances of catching up to be hopeless, they sometimes get frustrated and angry, and some become terrorists, or tolerate or support terrorists. Since Sept. 11, 2001, it has become clear that the oceans that once protected the United States no longer do so. There will be more terrorist attacks against us and Europe, and perhaps against Japan and Australia, as long as that factorial difference of 32 in consumption rates persists.”

“Just as it is certain that within most of our lifetimes we’ll be consuming less than we do now, it is also certain that per capita consumption rates in many developing countries will one day be more nearly equal to ours. These are desirable trends, not horrible prospects. In fact, we already know how to encourage the trends; the main thing lacking has been political will.”

Posted by: Minhyong Kim on January 1, 2009 1:21 AM | Permalink | Reply to this

Re: Science and the Environment

Minhyong quoted Jared Diamond as saying:

There will be more terrorist attacks against us and Europe, and perhaps against Japan and Australia, as long as that factorial difference of 32 in consumption rates persists.

I’ve heard different opinions about this ‘common knowledge’. It’s not clear to me that terrorist attacks against the US and Europe are caused by our greater wealth or consumption of resources. After all, there have also been serious terrorist attacks in Indonesia, India and other countries. And if you listen to what the Al Qaeda people say, they seem a lot more concerned about the battle between Islam and other religions, than some sort of struggle for economic equality.

I don’t know — I just want to point out that it’s a slippery business. Here are some quotes by bin Laden. Maybe it pays to think about his self-proclaimed motivations. He certainly wasn’t poor: his father was a rich Saudi businessman!

In 2004 Osama bin Laden said:

God knows it did not cross our minds to attack the towers but after the situation became unbearable and we witnessed the injustice and tyranny of the American-Israeli alliance against our people in Palestine and Lebanon, I thought about it. And the events that affected me directly were that of 1982 and the events that followed – when America allowed the Israelis to invade Lebanon, helped by the U.S. Sixth Fleet. As I watched the destroyed towers in Lebanon, it occurred to me punish the unjust the same way (and) to destroy towers in America so it could taste some of what we are tasting and to stop killing our children and women.

And, asked in 1998 if he was trying to acquire chemical and nuclear weapons:

Acquiring weapons for the defense of Muslims is a religious duty. If I have indeed acquired these weapons, then I thank God for enabling me to do so. And if I seek to acquire these weapons, I am carrying out a duty. It would be a sin for Muslims not to try to possess the weapons that would prevent the infidels from inflicting harm on Muslims.

Posted by: John Baez on January 1, 2009 2:41 AM | Permalink | Reply to this

Re: Science and the Environment

I agree that it’s all very slippery. So perhaps it’s a good idea to avoid using the slippery term ‘terrorism’ in this context, when what Diamond appears to be referring to are

`attacks on rich nations originating in poor nations.’

One crude mistake in my previous post was the term ‘common knowledge,’ as you correctly point out, when I’m not sure I agree even with the general economic observations. What I meant to apologize for was simply the overall redundancy of the article, albeit still worth a read.

However, to be fair, I believe it’s reasonable to interpret Diamond’s paragraph as referring to *root causes*. That is, the point being made appears to be:

Economic inequality is the root cause of ARNOPN in the world.

We might compare it to a thesis like:

Economic inequality is the root cause of racially-based resentment in the US (also manifesting itself in violent action with some frequency).

Even though it’s also a simplification, my feeling is that it is one whose judgment a substantial portion of the concerned citizenry considers fair enough to accept. In any case, inconsistencies in the writings of specific leaders are largely independent of its validity.

Posted by: Minhyong Kim on January 2, 2009 12:58 AM | Permalink | Reply to this

Re: Science and the Environment

I agree it’s a very complicated picture (and I don’t claim to understand it). But part of what Jared Diamond appears to be saying is that, whatever the motivation of the “actual” terrorists, there’s also the question of if there are factors which motivate the “general community” (who don’t commit terrorism themselves) to view it as “in their view legitimate” and, eg, not report suspicious things, not oppose those clearly doing recruiting, etc. And this sort of thing clearly applies to many terrorist conflict situations both now and in the past, not just the ones uppermost in the American psyche.

I’m suspicious of a “view of excess consumption” rather than, say, “a view of imperialism”, “a view of international double-standards”, etc, being more significant in the general communities in various places.

That’s not to say we shouldn’t attempt to make consumption more equitable, just that I don’t think it’s a key component in terrorism.

Posted by: bane on January 1, 2009 5:24 PM | Permalink | Reply to this

Re: Science and the Environment

Perhaps my comment on root causes above applies here as well.

Posted by: Minhyong Kim on January 2, 2009 1:02 AM | Permalink | Reply to this

Re: Science and the Environment

I share your excitement about our new science policy leaders. If the culture of fact driven search for excellence is spread to other part of government, there are some wonderful reform possibilities that can be realized in the next 4 years.

As scientists, we have to stand up for our values; educate and organize to make change possible.

Posted by: Thomas on December 27, 2008 8:12 AM | Permalink | Reply to this

Re: Science and the Environment

Here’s how some scientists are trying to save the world. This is an email from the president of the New England Complex Systems Institute, Yaneer Bar-Yam:

Happy Holidays!

As we complete the year, I wanted to share with you important accomplishments of NECSI in 2008 and acknowledge those who made them possible. It is gratifying to see the increasing awareness of the scientific importance of Complex Systems and its application in large-scale problem solving.

Large-Scale Problem Solving

1. Global economic crisis:

The Crash of 2008, a global financial crisis, is the deepest recession since the Great Depression in the 1920s. NECSI has undertaken to identify factors that may be responsible for a dynamic instability of this magnitude. Our studies indicate that a single action by the US Securities and Exchange Commission (SEC) repealing a rule that was implemented shortly after the Great Depression may be responsible for destabilizing the markets. Such an instability means that any disturbance would cause a financial crisis and crash. We are working to inform policy with the results of our scientific analysis so that the rule will be reinstated as an essential step to economic recovery.

http://www.necsi.edu/research/economics/

2. Healthcare:

Increasing the delivery of only five preventive services would save 100,000 lives per year in the US alone. NECSI has collaborated with the CDC on how to improve the delivery of preventive services. Our analysis builds on our previous work published in the American Journal of Public Health showing that the structure of organizations that are well suited to deliver acute care are not necessarily the best for preventive care. We detail the dramatic health and financial benefits to delivery of services through different organizations. We are working to inform the medical, business and policy community with the results of our scientific analysis. Other projects in healthcare include methods for dramatic reduction in hospital based infections.

http://www.necsi.edu/research/management/health

3. Global vulnerabilities — ecological, social, and economic: The global economic crisis is only one example of how global systems become vulnerable to instabilities that arise in one part of the system but affect the entire system due to interdependencies. NECSI has studied the impact of global connectivity in evolutionary systems, with direct relevance to pandemics of emergent diseases, invasive species, and, by extension, economic disasters. Our results show that while systems with many local spatial contexts are robust to exploitation, globally connected systems become vulnerable to global destruction at even low levels of connectivity. We continue to give presentations and write about the need for careful planning of global policy and scientific analysis (complex systems!). Our work is widely noted in popular press on global vulnerabilities.

http://www.necsi.edu/headlines/ecofinancial.html

http://www.necsi.edu/headlines/newscientist.html

Advanced Research on Complex Systems

4. Evolutionary dynamics:

Our review article in the journal Complexity reveals limits of traditional views of evolutionary dynamics. Among the insights are:

Fitness cannot be treated as a property of individual genes or individual organisms when local contexts vary (symmetry breaking causes averaging approximations to fail).

In a spatial system organisms inherit the environment that is affected by their parents.

Overexploiting organisms may have many offspring but their descendants suffer the consequences.

Altruism arises in evolution because selfish individuals diminish the survivability of their descendants.

Now, let’s see what we have in store for next year.

Currently Planned Projects for 2009

– We plan to continue our rapid response to the economic crisis, extending our analysis and engaging with policy makers.

– We plan to engage with healthcare policy discussions in the new US administration and hope to extend our work to healthcare systems in other countries including the developing world.

– The problem of ethnic violence continues to be a major source of death and suffering globally. We are continuing our work on the prediction and prevention of ethnic violence.

– The problem of global biodiversity and its vulnerability requires fundamental understanding of its origins and dynamics. We are pursuing this scientific understanding, building upon our previous studies.

– In advanced research on complex systems we plan to publish new work on multiscale analysis and the complexity profile, and on networks

Other projects will be described as the year progresses.

I would like to thank our co-faculty, board members, and affiliates for their ongoing help. Furthermore, our accomplishments would not have been possible without the administrative staff and post-docs/students at NECSI. And, above all, thanks to you for being a Complex Systems community member.

Posted by: John Baez on December 30, 2008 4:18 AM | Permalink | Reply to this

Re: Science and the Environment

Perhaps something you might usefully do is explain how you have come to be convinced about the strength of the AGW-carbon emissions link. No doubt there are many people like me who feel the pull of both sides in the climate change debates. I don’t know how anyone feels confident enough to make quantitative predictions five decades hence, such as Pacala and Socolow, when surprises seem to turn up daily, e.g., on changes to reflectance post-1998. But something that stands a reasonable chance of being resolved concerns the physics of absorption of radiation by CO 2CO_2.

The closest I’ve seen to a clear explanation of the skeptical point of view comes from the first entry of this search and references therein. Perhaps you’d rather not be pointed to someone who has not always been complimentary about you, but anyway presumably you have countervailing reasons against the logarithmic formula for the greenhouse effect.

Posted by: David Corfield on January 2, 2009 4:06 PM | Permalink | Reply to this

Re: Science and the Environment

David wrote:

Perhaps something you might usefully do is explain how you have come to be convinced about the strength of the AGW-carbon emissions link.

Okay, maybe I should do this sometime — not in this blog entry, though.

I don’t know how anyone feels confident enough to make quantitative predictions five decades hence, such as Pacala and Socolow, when surprises seem to turn up daily, e.g., on changes to reflectance post-1998.

I take all quantitative predictions of long-term trends with a large grain of salt. If a bunch of numbers turn out to be off by a factor of 2, I won’t be surprised. I’ll probably consider them to have been correct.

The challenge is figuring out what to do in situations where the stakes are high but there’s a lot of uncertainty. A good basic principle, repeatedly emphasized here by Bane, is that it’s good to focus on doing things that will be helpful even if your predictions are off — and things that are unlikely to have disastrous side-effects. I think this is one reason Chu and Holdren (see my blog entry) are so gung-ho about increasing efficiency — as opposed to, say, putting millions of tons of sulfur dioxide into the upper atmosphere.

Posted by: John Baez on January 2, 2009 8:33 PM | Permalink | Reply to this

Re: Science and the Environment

David,

There aren’t any countervailing arguments against the logarithmic relationship between atmospheric CO2 concentration and its radiative forcing: this is widely accepted among climate scientists. Well, it’s not exactly true, there are small deviations which show up in radiative transfer codes, but it’s a good approximation in the absence of system feedbacks and is commonly used in simpler models without their own radiative transfer codes.

The calculation you link is for the non-feedback climate sensitivity, and it assumes about 1 C of warming for 2xCO2. This is not controversial either: climatologists usually take its value to be 1.1 or 1.2 C. But that’s not the sensitivity we actually experience, because there are many feedback effects present (due to water vapor, snow and ice albedo, clouds, etc.). The IPCC judges that these feedbacks elevate the real-world climate sensitivity from ~1 C to between 1.5 and 4.5 C.

Informed debates about climate change are not about whether the greenhouse effect of CO2 is real, since the 1 C figure is widely accepted. Rather, the debate is about how strong the amplifying feedback effects are. The IPCC uses a central value of about 3 C in many of its projections, so if you think feedbacks are weak and the true sensitivity is closer to the no-feedback 1 C, then you think that global warming is being over-estimated. There is legitimate debate within the climate science community about whether the true climate sensitivity is closer to the lower end or the upper end of the canonical IPCC range.

You should be aware, by the way, that many of the explanations you can find on the web which purport to demonstrate a very low (feedback) climate sensitivity make one of a series of common errors, such as: (1) using a too-crude model of heat diffusion into the oceans such as treating the atmosphere and ocean as a combined slab of uniform heat capacity (or worse, neglecting the difference between the transient and equilibrium response altogether by ignoring the rate of heat uptake), (2) neglecting some of the forcing agents present (such as the direct and indirect effects of aerosol cooling), (3) neglecting feedback effects (if performing a “first principles” calculation), (4) neglecting some of the available observations (such as using surface temperature data but not ocean heat data), or (5) ignoring the uncertainty in observations and estimated parameters.

In addition, we have to worry whether the long-term climate sensitivity may ultimately prove to be greater than what can be estimated from current data, if large feedback effects kick in later which are not yet present (such as disintegration of large ice sheets, substantial ecosystem responses in the terrestrial carbon cycle, etc.) Of course, it’s also possible that new large negative feedbacks could kick in later, too.

Posted by: Nathan Urban on January 6, 2009 2:51 PM | Permalink | Reply to this

Re: Science and the Environment

Thanks, that’s helpful. In your opinion are there parallel errors made in some of the explanations for very high climate sensitivity?

So the improved request to John is to explain why he is inclined to the higher end of the feedback scale.

Posted by: David Corfield on January 6, 2009 4:01 PM | Permalink | Reply to this

Re: Science and the Environment

David,

I don’t know whether anything John has said implies that he’s inclined to the higher end of the sensitivity range. The usual IPCC-type projections that John frequently talks about are typically based on the *middle* range (~3 C).

The high end of the climate sensitivity range has also been criticized, most notably in some of the published ClimatePrediction.net results (kind of the climate analog of SETI@Home). The criticism there is that the models haven’t been confronted with a sufficiently wide array of observational constraints, i.e. there may be data constraints which could potentially rule out high sensitivities.

This is a frequent debate between physical modelers (who tend to get values in the middle of the IPCC range) and those who try to produce more data-based estimates. The modelers say the data guys don’t use enough data; the data guys say the modelers just use best guesses and don’t ever check to see if their models can produce high sensitivities. Both criticisms are valid: nobody has yet produced a robust uncertainty analysis that also uses realistic models, mostly because of the computational expense but also because it’s tricky to statistically combine all the data constraints properly accounting for their spacetime covariance and cross-constraint correlations.

There are fundamental physical reasons why it’s hard to rule out high sensitivities a priori. For why it’s hard to rule out from a first-principles physical calculation, see Roe and Baker (2007). (Basic reason: there is a nonlinear relationship between what you calculate, which is the feedback factor, and what you want to know, which is the sensitivity.) For why it’s hard to rule out from observational data, see Allen et al., “Observational constraints on climate sensitivity”, in Avoiding Dangerous Climate Change (2006), as well as Urban and Keller (2009) (in press).

On a more general note, Knutti and Hegerl (2008) is the best current overview of climate sensitivity research. In my opinion, the best available observational estimates of climate sensitivity are Tomassini et al. (2007) and Sanso et al. (2008). Sanderson et al. (2008) is also interesting (based on the CP.net ensemble), because it has a large ensemble and a fair number of constraints, but it’s statistically weak. For model-based estimates, the IPCC AR4 WG1 report (chapter 8) probably still has the best summary. (Chapter 9 has an analogous section on observational estimates.) Knutti et al. (2008) is a good summary of what this all means for 21st century temperature projections.

Posted by: Nathan Urban on January 6, 2009 10:04 PM | Permalink | Reply to this

Re: Science and the Environment

I forgot to mention the corresponding limitation on our ability to observationally exclude high climate sensitivities. From a “calculate all the individual feedbacks” approach, I said that the limitation is the nonlinearity between feedback and sensitivity (the Roe and Baker paper). From a “observationally constrain the total sensitivity” approach, the corresponding limitation is the nonlinearity between transient and equilibrium response. (Since the climate doesn’t equilibrate instantly. Actually it doesn’t equilibrate at all; “equilibrium climate sensitivity” is a convenient fiction.) Also, we haven’t yet forced the system very much, and there is uncertainty in the forcing, the response time, and the response.

I also forgot to mention paleo-observational constraints on sensitivity; we don’t have to use just modern data. Unfortunately, the uncertainties in both forcing and response are much larger, and few studies have treated both uncertainties carefully. I’m keeping my eye on the UK PalaeoQUMP project in that regard.

Posted by: Nathan Urban on January 6, 2009 10:57 PM | Permalink | Reply to this

Re: Science and the Environment

Here’s a genuine question (which isn’t trying to presuppose a result). There’s two questions:

(1) given the current limited data and models, what actions should human beings take about possible AGW? Take as read that some of both the data and the models will inevitably contain flaws, it’s just a case of how much they influence the conclusions.

(2) The standard kind of inference scenario, eg, the famous “Your burglar alarm has gone off. This might happen because of a break in, or of an (rare) earthquake. And the fact that you haven’t yet heard any reports of an earthquake on the radio. There’s something about wet lawns and sprinklers influencing things as well. (It’s a bizarrely intertwined situation :-) .) It’s going to cause you some specified amount of inconvenience to go home to see if there is a burglarly. Do you go home?” In this scenario we assume that you can guesstimate the probabilities of things like “the probability there has been an earthquake that hasn’t been reported on the radio yet”, but that they are of the sort where you don’t think there is an “exact frequentist probability” that you could determine if you did enough experiments, so the guesstimates are about as “fine-grained” as you’re going to get. (The kind of scenario Judea Pearl has in his books on inference in graphical models and causality, although I’m sure other reasoning approaches must use it. Here is the first example google gives for it, although I’m sure there are clearer presentations.)

Lets also take as read that in (1) more research that will eventually eliminate essentially all the uncertainty should always be done, but that results that significantly reduce the unceratinty (over the big picture question) will not be available before the time when a decision to do action X (say, imposing a higher tax on vehicle fuel, or leaving work early to check your house) or to not do action X.

Is there a difference in how one ought to act in these different scenarios, deriving from the difference that in (1) there one can in principle obtain full knowledge but in practice it isn’t obtainable immediately, whilst in (2) a certain level of uncertainty is “irreducible”? The bit I’m really interested in is, if there is a difference in behaviour, what is the reason for this?

Posted by: bane on January 7, 2009 1:33 PM | Permalink | Reply to this

Re: Science and the Environment

No, I don’t think there’s any difference between the two, if you postulate that in case (1) you don’t learn anything useful before the decision point, and there is only one, irreversible decision to be made.

What matters to the decision is the uncertainty at the time you have to make the decision, not your potential uncertainty after the decision is made. It doesn’t really matter whether further research could potentially eliminate uncertainty, if in practice it can’t actually do so before you have to make a decision.

(This changes, of course, in sequential decision-making, where you can learn-act-learn-act-…)

Posted by: Nathan Urban on January 7, 2009 3:01 PM | Permalink | Reply to this

Re: Science and the Environment

Thanks. I was partly asking because David Cofrield is in the interesting position of both a philosopher of science but also someone who worked in a machine learning group for a couple of years, so whether he thinks there is a difference would be a view taking into account both viewpoints.

Posted by: bane on January 7, 2009 3:31 PM | Permalink | Reply to this

Re: Science and the Environment

Yes, I agree with Nathan that there is no difference. Mind you the full decision problem is horrendously complicated when you factor in the expense of possible investigations. You need to weigh these with expectations of how uncertainty might be reduced by such investigations. Also with finite resources, you might consider that it’s better delaying investigations until better techniques are devised, and you may have a probabilistic representation of the chances of these techniques being devised.

Posted by: David Corfield on January 8, 2009 11:19 AM | Permalink | Reply to this

Re: Science and the Environment

Hi, Nathan! Long time no see! It’s great to see a post from you here.

How come you know so much about this stuff? Just general interest, or are you actually getting involved in it somehow?

Posted by: John Baez on January 6, 2009 7:00 PM | Permalink | Reply to this

Re: Science and the Environment

John,

I am indeed involved in this now; I switched fields and have been doing a postdoc in climate change for the last two years. I put my academic website in the URL field if you want to check out what I’ve been up to.

Posted by: Nathan Urban on January 6, 2009 9:49 PM | Permalink | Reply to this

Re: Science and the Environment

Dear John,

This is the first time since 2 years that I dare look at this magnificent place. I had to abstain in order to keep sane, i.e. get sleep and my jobs done and not let my head explode.

One reason is, this blog is one of my old tech dreams come true (more or less), the Internet University. If only I were at grad school now, not 10y ago with I-illiterate profs who wouldn’t even allow me a decent computer in my office… sigh.

You are perhaps not contributing much to save the biosphere. But there’s way no reason to feel bad about it, for you. You have contributed enough to science communication (specialized as it may be) to have earned sainthood.

You might feel bad about your many air travels. Forget about it. It is enough you abstain from superfluous air travel, e.g. better go on vacation by bike or hike in the remains of California’s great natural treasures. You actually contributed a lot to make science communication more effective. That offsets your (and other important heads’) carbon foot/brainprints.

Beyond saving the biosphere there’s another important project, “Lovelock’s book”, i.e. preservation of the knowledge gathered by mankind. Methinks there you can contribute most effectively. You write the math chapter, so to say, by continuing development of blogs/wikis like this.

One of my other dreams was the Internet Bourbaki.

Posted by: Florifulgurator on January 9, 2009 6:27 PM | Permalink | Reply to this

Re: Science and the Environment

Florifulgurator wrote:

This is the first time since 2 years that I dare look at this magnificent place. I had to abstain in order to keep sane, i.e. get sleep and my jobs done and not let my head explode.

I know what you mean. If I tried hard to understand everything said here, I wouldn’t get any work done either.

You have contributed enough to science communication (specialized as it may be) to have earned sainthood.

Sainthood? Cool! That’s always been my ambition, but I was far too modest to admit it.

Seriously, I’m glad you think I’ve been doing some useful things… but I want to do more.

One of my other dreams was the Internet Bourbaki.

There’s been some discussion of ‘iBourbaki’ on the category theory mailing list. André Joyal was really pushing this idea.

But I’m hoping that someday the real Internet Bourbaki will be the nLab!

Posted by: John Baez on January 23, 2009 5:38 AM | Permalink | Reply to this

Re: Science and the Environment

Saul Griffith is a Californian inventor who received a MacArthur “genius” award in 2007. Here is Stewart Brand’s summary of a talk by Griffith at the Long Now Seminar. The talk was called ‘Climate Change Recalculated’.

Engineer Griffith said he was going to make the connection between personal actions and global climate change. To do that he’s been analyzing his own life in extreme detail to figure out exactly how much energy he uses and what changes might reduce the load. In 2007, when he started, he was consuming about 18,000 watts, like most Americans.

The energy budget of the average person in the world is about 2,200 watts. Some 90 percent of the carbon dioxide overload in the atmosphere was put there by the US, USSR (of old), China, Germany, Japan, and Britain. The rich countries have the most work to do.

What would it take to level off the carbon dioxide in the atmosphere at 450 parts per million (ppm)? That level supposedly would keep global warming just barely manageable at an increase of 2 degrees Celsius. There still would be massive loss of species, 100 million climate refugees, and other major stresses. The carbon dioxide level right now is 385 ppm, rising fast. Before industrialization it was 296 ppm. America’s leading climatologist, James Hanson, says we must lower the carbon dioxide level to 350 ppm if we want to keep the world we evolved in.

The world currently runs on about 16 terawatts (trillion watts) of energy, most of it burning fossil fuels. To level off at 450 ppm of carbon dioxide, we will have to reduce the fossil fuel burning to 3 terawatts and produce all the rest with renewable energy, and we have to do it in 25 years or it’s too late. Currently about half a terawatt comes from clean hydropower and one terawatt from clean nuclear. That leaves 11.5 terawatts to generate from new clean sources.

That would mean the following. (Here I’m drawing on notes and extrapolations I’ve written up previously from discussion with Griffith):

“Two terawatts of photovoltaic would require installing 100 square meters of 15-percent-efficient solar cells every second, second after second, for the next 25 years. (That’s about 1,200 square miles of solar cells a year, times 25 equals 30,000 square miles of photovoltaic cells.) Two terawatts of solar thermal? If it’s 30 percent efficient all told, we’ll need 50 square meters of highly reflective mirrors every second. (Some 600 square miles a year, times 25.) Half a terawatt of biofuels? Something like one Olympic swimming pools of genetically engineered algae, installed every second. (About 15,250 square miles a year, times 25.) Two terawatts of wind? That’s a 300-foot-diameter wind turbine every 5 minutes. (Install 105,000 turbines a year in good wind locations, times 25.) Two terawatts of geothermal? Build 3 100-megawatt steam turbines every day-1,095 a year, times 25. Three terawatts of new nuclear? That’s a 3-reactor, 3-gigawatt plant every week-52 a year, times 25.”

In other words, the land area dedicated to renewable energy (“Renewistan”) would occupy a space about the size of Australia to keep the carbon dioxide level at 450 ppm. To get to Hanson’s goal of 350 ppm of carbon dioxide, fossil fuel burning would have to be cut to ZERO, which means another 3 terawatts would have to come from renewables, expanding the size of Renewistan further by 26 percent.

Meanwhile for individuals, to stay at the world’s energy budget at 16 terawatts, while many of the poorest in the world might raise their standard of living to 2,200 watts, everyone now above that level would have to drop down to it. Griffith determined that most of his energy use was coming from air travel, car travel, and the embodied energy of his stuff, along with his diet. Now he drives the speed limit (no one has passed him in six months), seldom flies, eats meat only once a week, bikes a lot, and buys almost nothing. He’s healthier, eats better, has more time with his family, and the stuff he has he cherishes.

Can the world actually build Renewistan? Griffith said it’s not like the Manhattan Project, it’s like the whole of World War II, only with all the antagonists on the same side this time. It’s damn near impossible, but it is necessary. And the world has to decide to do it.

Griffith’s audience was strangely exhilarated by the prospect.

–Stewart Brand

Posted by: John Baez on January 17, 2009 9:20 PM | Permalink | Reply to this

numbers from 2 PhDs; Re: Science and the Environment

I emailed that Renewistan talk to two PhD Physicists I know, but forget to ask their permission to cite them by name. Comments:

“Two terawatts of photovoltaic would require installing 100 square meters of 15-percent-efficient solar cells every second, second after second, for the next 25 years. (That’s about 1,200 square miles of solar cells a year, times 25 equals 30,000 square miles of photovoltaic cells.)

That’s about right; southern Nevada has an annually-averaged incident solar radiation (“insolation”) of 5 kW-hr/m^2, so at 15% efficiency, I calculate 32 square miles required per average gigawatt if you put the panels there.

In other words, the land area dedicated to renewable energy (“Renewistan”) would occupy a space about the size of Australia to keep the carbon dioxide level at 450 ppm.


According to Wikipedia the area of Australia is 7,741,220 km2 = 2,988,902 sq mi., which is two orders of magnitude greater than the 30,000 square miles you quote for the required area of PV.

30,000 square miles is roughly the size of Lincoln and Nye counties, Nevada, put together (population 37,000, slightly over one per square mile). Actually you’d prefer to put the panels in Clark county (a little sunnier than the number I calculated), but you probably can’t afford to buy Las Vegas.

============

southern Nevada has an annually-averaged incident solar radiation (“insolation”) of 5 kW-hr/m^2


I inadvertantly left out “per day” there.

5 kW-hr/m^2 per day = 208 W/m^2 average.
For 15% efficient solar cells, that comes to an output of 31 watts average power per square meter covered.

Slightly more in the southern tip of Nevada.

============

I’ve usually used 12.5% averaged efficiency (1/8 is a nice number) given the temperature dependence and dust and pigeons and conversion inefficiencies; with a factor of 1/6 for overall angle and clouds (or 0.5 kWh/m^2/day starting from 1 kW/m^2). This is an average of slightly more than 20 W/m^2 or 2e7 W/km^2. Therefore 2 TW requires 100000 km^2. Of course, this doesn’t do anything about storage or long-distance transmission. It’s a bit bigger as it assumes 4 rather than 5 kWh/day as a base and less efficiency, but it matches real installations.

California averages about 30 GigaWatts (this includes some areas not in Cal-ISO) just for comparison. Of course, it’s a bit of a cheat to say land area has to be “dedicated” to solar energy — a typical house roof in Los Angeles is larger than 100m^2, and therefore can generate 2kW continuous if covered with 12.5% efficient panels and not shaded.

In Los Angeles, at least, the main barriers are 1) it costs 50 cents a kWh installed assuming a 40-year lifetime (given a 6% annual cost of money) and 2) there are laws prohibiting the removal of trees.

A more interesting question is the amount of embedded energy in creating, installing and connecting solar panels. A very rough rule of thumb is that the embedded energy of a high-tech item is about a quarter of its total retail cost, so that says the energy embedded in an installed solar panel is not small — given that a m^2 installed panel supplies 20 W average and costs about 600 dollars.

Posted by: Jonathan Vos Post on January 21, 2009 6:01 PM | Permalink | Reply to this

Re: numbers from 2 PhDs; Re: Science and the Environment

there are laws prohibiting the removal of trees

I don't know about local regulations in Los Angeles, but in California generally, you can cut down trees to unshade solar panels.

There was a case in northern California where one person with solar panels tried to force their neighbour to cut down some redwoods (!). http://www.foxnews.com/story/0,2933,331551,00.html

Posted by: Toby Bartels on January 22, 2009 10:59 PM | Permalink | Reply to this

Re: Science and the Environment

Steward Brand wrote:

The world currently runs on about 16 terawatts (trillion watts) of energy, most of it burning fossil fuels. To level off at 450 ppm of carbon dioxide, we will have to reduce the fossil fuel burning to 3 terawatts […] Currently about half a terawatt comes from clean hydropower and one terawatt from clean nuclear. That leaves 11.5 terawatts to generate from new clean sources.

That would mean the following. (Here I’m drawing on notes and extrapolations I’ve written up previously from discussion with Griffith):

“Two terawatts of photovoltaic would require installing 100 square meters of 15-percent-efficient solar cells every second, second after second, for the next 25 years. (That’s about 1,200 square miles of solar cells a year, times 25 equals 30,000 square miles of photovoltaic cells.) Half a terawatt of biofuels? Something like one Olympic swimming pools of genetically engineered algae, installed every second. (About 15,250 square miles a year, times 25.) Two terawatts of wind? That’s a 300-foot-diameter wind turbine every 5 minutes. (Install 105,000 turbines a year in good wind locations, times 25.) Two terawatts of geothermal? Build 3 100-megawatt steam turbines every day-1,095 a year, times 25. Three terawatts of new nuclear? That’s a 3-reactor, 3-gigawatt plant every week-52 a year, times 25.”

[…]

In other words, the land area dedicated to renewable energy (“Renewistan”) would occupy a space about the size of Australia to keep the carbon dioxide level at 450 ppm.

JVP quoted an unnamed PhD physicist as saying:

According to Wikipedia the area of Australia is 7,741,220 km2 = 2,988,902 sq mi., which is two orders of magnitude greater than the 30,000 square miles you quote for the required area of PV.

Good point.

The 2 terawatts of photovoltaic solar power mentioned by Stewart Brand was only a portion of the 11.5 terawatts required. It wasn’t clear how “the area of Australia” was arrived at.

If generating 2 terawatts of solar power requires 30,000 square miles, then generating all 11.5 terawatts would take about

(11.5 / 2) × 30,000 square miles = 170,000 square miles

The area of Australia is much larger: about 3,000,000 square miles.

I can get almost three times the size of Australia if I unrealistically imagine all the power being generated by algae. Brand wrote:

Half a terawatt of biofuels? Something like one Olympic swimming pools of genetically engineered algae, installed every second. (About 15,250 square miles a year, times 25.)

That gives about

25 × 15,250 = 380,000 square miles

for half a terawatt of biofuels. So, if we generated all 11.5 terawatts this way, it would take

(11.5 / .5) × 380,000 = 8,800,000 square miles

But, I doubt anyone plans to cover Australia with swimming pools of algae.

I’ll ask Brand about this.

Posted by: John Baez on January 22, 2009 11:59 PM | Permalink | Reply to this

Re: Science and the Environment

Here’s Stewart Brand’s reply:

The Australia line came from Saul, in relation to an earlier version, where 2 terawatts of power was to come from algae instead of half a terawatt. Also I gave the wind only in terms of turbines; they take up formidable acreage.

Posted by: John Baez on January 23, 2009 3:31 AM | Permalink | Reply to this

Re: Science and the Environment

Why would we need 11.5TW of renewable energy production in order to replace 11.5TW of fossil fuel based energy consumption? A 1MW coal plant probably needs about 3MW of coal to make that 1MW of electricity, because converting chemical energy to electricity is pretty darn inefficient, while a 1MW wind farm is just a 1MW wind farm. Most renewables like solar PV and wind turbines output electricity to a grid or make it at the point of use, so we don’t need to replace world energy consumption of fossil fuels tit for tat with renewable energy production as far as I know.

Granted, this depends heavily on the application. Blast furnaces aren’t exactly something where we could easily substitute coal with electricity from wind turbines, and freight is one of those situations where we need the high energy density of liquid fuels, but something like an electric vehicle only requires about a half to a quarter of the energy a conventional vehicle with a SI engine does, all things being equal. Indoor climate control is similar in that we could probably replace however many BTUs of natural gas or heating oil with roughly the same number of BTUs from a heat pump while using a quarter of the energy give or take.

MacKay’s book is a great example of stuff like this, although IMO further versions should look more at industry, but I suppose I’m just being picky. Anyway, the point is that the amount of renewable energy production we would need to replace fossil fuel energy consumption depends on the application.

Posted by: Anonemouse on February 1, 2009 9:07 AM | Permalink | Reply to this

Re: Science and the Environment

David wrote:

So the improved request to John is to explain why he is inclined to the higher end of the feedback scale.

Nathan wrote:

I don’t know whether anything John has said implies that he’s inclined to the higher end of the sensitivity range. The usual IPCC-type projections that John frequently talks about are typically based on the middle range (~3 C).

Yeah, I’m not trying to play the climate science expert. I’m mainly trying to accurately reflect what seems to be the scientific consensus.

On a more general note, Knutti and Hegerl (2008) is the best current overview of climate sensitivity research. In my opinion, the best available observational estimates of climate sensitivity are Tomassini et al. (2007) and Sanso et al. (2008). Sanderson et al. (2008) is also interesting (based on the CP.net ensemble), because it has a large ensemble and a fair number of constraints, but it’s statistically weak. For model-based estimates, the IPCC AR4 WG1 report (chapter 8) probably still has the best summary. (Chapter 9 has an analogous section on observational estimates.) Knutti et al. (2008) is a good summary of what this all means for 21st century temperature projections.

Thanks for all references! A month’s worth of bedtime reading! But right now I’m busy having fun with Snowball Earth by Gabrielle Walker — a good pop history of the Snowball Earth theory. You might like that.

And when I’m done with that, it’s the Paleoecology of Beringia. I’m fascinated by the ‘productivity paradox’: how did woolly mammoths survive in northern lands during the last glacial period, when there doesn’t even seem to be enough food there to support them now?

I switched fields and have been doing a postdoc in climate change for the last two years.

Great! Excellent move! I’m glad you got out of quantum gravity.

I put my academic website in the URL field if you want to check out what I’ve been up to.

Will do! I may have a bunch of questions, someday.

Posted by: John Baez on January 23, 2009 5:27 AM | Permalink | Reply to this

Re: Science and the Environment

John wrote:

But right now I’m busy having fun with Snowball Earth by Gabrielle Walker — a good pop history of the Snowball Earth theory. You might like that.

Cool, I hadn’t heard of that. We have a couple of good people here who publish on Snowball Earth, by the way (Jim Kasting and Lee Kump).

Although I work mostly on modern climate, I’m getting more interested in paleoclimate. I’m fascinated by the kinds of climate information that be inferred from proxy data. I finished reading Ice, Mud, and Blood by Chris Turney and am now starting The Long Thaw by David Archer. (His Understanding the Forecast book is a good overview of modern climate science.)

I’m fascinated by the ‘productivity paradox’: how did woolly mammoths survive in northern lands during the last glacial period, when there doesn’t even seem to be enough food there to support them now?

I’m curious about why they went extinct, myself.

Great! Excellent move! I’m glad you got out of quantum gravity.

Me too. I’m not happy with how the field has progressed since I left quantum gravity (or rather, how it hasn’t). As for my new field, I just kind of stumbled into it, and found it to my liking: very interdisciplinary with broad collaborative opportunities, lots of thorny statistics, and interesting and relevant decision analysis questions.

Will do! I may have a bunch of questions, someday.

Feel free to ask whatever you like. You’ve certainly spent enough time answering my questions! I can’t promise the best answers, as I’m new to the field myself, but I have a handle on certain areas of the literature (such as climate sensitivity).

Posted by: Nathan Urban on January 27, 2009 8:58 PM | Permalink | Reply to this

Re: Science and the Environment

Nathan wrote:

I finished reading Ice, Mud, and Blood by Chris Turney and am now starting The Long Thaw by David Archer.

I’ll check ‘em out. Speaking of long thaws, I love this book:

  • Evelyn C. Pielou, After the Ice Age: the Return of Life to Glaciated North America, U. Chicago Press, Chicago, 1991.

I wrote a longish summary on my diary. It makes quite vivid the strange landscape of North America when the glaciers were receding.

For example, one of the strangest features of North America at the end of the last Ice Age were the large regions of "stagnant ice". As the glaciers retreated, ice became buried by sediments called glacial till and wind-borne dust called loess. The ice was thick and well insulated, so it lasted for a long time. For example, in North Dakota there was a 60-kilometer wide zone of stagnant ice! It started out being as much as 100 meters thick! It lasted from 10,000 BC to 7,000 BC. The signs of its presence are still visible now.

Quoting from After the Ice Age:

The ice in stagnant ice terrain was for the most part buried deep, too deep for it to influence the environment on the surface. But this was not the case everywhere. There were occasional thin spots or even gaps in the insulating drift blanket, and here the ice began to melt. It melted in summer sun and dissolved in summer rain. Meltwater and rainwater together must have formed rivulets that drained into crevasses and then spread laterally, eroding a network of tunnels and caverns in previously insulated ice. Even while forest was in the process of developing over much of the area, the ground was crumbling here and there, where the stagnant ice had become honeycombed and weak around the thin spots and where cavern roofs caved in.

At the surface, the scene was one of sudden subsidences of the ground where the ice had given way beneath. Patches of forest sank into hollows, drowing the terrestrial plants. Much of the forest was "drunken forest," with trees leaning in every direction owing to the instability of the ground. On a small scale, the topography was continually changing. Sometimes the slumping exposed a cliff of ice, which would begin to melt as soon as it was exposed to sunlight and air. Innuerable little superglacial puddles and pools were formed because of the subsidences. They were icy cold and probably, like glacial lakes today, milky with rock flour; as environments for life, they were unpromising.

The continued melting of the ice where it was poorly insulated improved insulation. The negative feedback process that allowed melting ice to slow its own melting worked as follows: the ice was "dirty," with embedded rocks (how dirty is not known), and as the surface gradually sank lower at the thin spots because of melting, the rocks were released from their icy matrix and acuumulated. Thus, in time, the thin spots in the original insulation automatically repaired themselves, and the melting slowed considerably. The insulation was also augmented everywhere by wind-borne dust from the zone of newly exposed land next to the ice sheet margin (which was not far away to begin with) and by accumulating forest floor litter, humus, and soil.

[…]

It is known from studies made in Alaska that a drift layer two meters thick insulates surface lakes from buried ice completely.

Gradually the insulation became absolute. Gradually the terrain became less active in the sense that slumps and subsidences became less and less frequent. The melting of the buried ice (which continued to melt, of course, or it would be there still) came to be caused entirely by the earth’s internal heat. And meltwater from the buried ice contributed progressively less to the lakes until they were supplied entirely by precipitation.

[…]

Stagnant ice terrain finally ceased to exist when the last of the buried ice melted, about 9k B.P. [that is, 9000 years ago, or 7000 BC]. At first, lakes that had been superglacial were led down onto bedrock, becoming so-called ice-walled lakes for as long as the surrounding ice remained. The last blocks to melt left the holes occupied by modern prairie potholes. All the land surfaces gently collapsed, because of the disappearance of the ice that had supported them. The lowered land levels allowed the ice-walled lakes to drain, and their sediments, which had accumulated layer upon layer to a considerable thickness, were left high and dry as flat-topped hills.

By the end of the melting period, at about 9k B.P., a reversal of the original topography had taken place, so that the fossils of lake-dwelling organisms are found on what are now hill tops.

Posted by: John Baez on January 28, 2009 1:24 AM | Permalink | Reply to this

Re: Science and the Environment

An interview with James Lovelock gives another slant on the issues raised by Saul Griffith. Here are a few selected quotes. He seems to agree with the idea, noted above, that wind power requires vast amounts of area. He’s less optimistic about our ability to build ‘Renewistan’:

Question: Your work on atmospheric chlorofluorocarbons led eventually to a global CFC ban that saved us from ozone-layer depletion. Do we have time to do a similar thing with carbon emissions to save ourselves from climate change?

Answer: Not a hope in hell. Most of the “green” stuff is verging on a gigantic scam. Carbon trading, with its huge government subsidies, is just what finance and industry wanted. It’s not going to do a damn thing about climate change, but it’ll make a lot of money for a lot of people and postpone the moment of reckoning. I am not against renewable energy, but to spoil all the decent countryside in the UK with wind farms is driving me mad. It’s absolutely unnecessary, and it takes 2500 square kilometres to produce a gigawatt - that’s an awful lot of countryside.

Question: So are we doomed?

Answer: There is one way we could save ourselves and that is through the massive burial of charcoal. It would mean farmers turning all their agricultural waste - which contains carbon that the plants have spent the summer sequestering - into non-biodegradable charcoal, and burying it in the soil. Then you can start shifting really hefty quantities of carbon out of the system and pull the CO 2CO_2 down quite fast.

Question: Would it make enough of a difference?

Answer: Yes. The biosphere pumps out 550 gigatonnes of carbon yearly; we put in only 30 gigatonnes. Ninety-nine per cent of the carbon that is fixed by plants is released back into the atmosphere within a year or so by consumers like bacteria, nematodes and worms. What we can do is cheat those consumers by getting farmers to burn their crop waste at very low oxygen levels to turn it into charcoal, which the farmer then ploughs into the field. A little CO 2CO_2 is released but the bulk of it gets converted to carbon. You get a few per cent of biofuel as a by-product of the combustion process, which the farmer can sell. This scheme would need no subsidy: the farmer would make a profit. This is the one thing we can do that will make a difference, but I bet they won’t do it.

Question: Do you think we will survive?

Answer: I’m an optimistic pessimist. I think it’s wrong to assume we’ll survive 2 °C of warming: there are already too many people on Earth. At 4 °C we could not survive with even one-tenth of our current population. The reason is we would not find enough food, unless we synthesised it. Because of this, the cull during this century is going to be huge, up to 90 per cent. The number of people remaining at the end of the century will probably be a billion or less. It has happened before: between the ice ages there were bottlenecks when there were only 2000 people left. It’s happening again.

I don’t think humans react fast enough or are clever enough to handle what’s coming up. Kyoto was 11 years ago. Virtually nothing’s been done except endless talk and meetings.

Read the rest to find out why he’s an ‘optimistic’ pessimist.

Having lots of poor people make charcoal and then bury it, instead of using it for fuel, seems tough.

Posted by: John Baez on January 23, 2009 5:52 PM | Permalink | Reply to this

Re: Science and the Environment

Yesterday I ran across this review paper on geoengineering by Lenton and Vaughan, which suggests biochar burial isn’t the panacea Lovelock seems to think: they estimate a potential ~35 ppm reduction in CO2 using this method. (Compare to the ~100 ppm current excess, and a potential ~1000 ppm or more in the future.) See Section 3.2.2. However, I’m not qualified to evaluate their assumptions about how much biochar could be realistically sequestered. They rely heavily on Lehman et al. (2006).

Posted by: Nathan Urban on January 29, 2009 3:34 PM | Permalink | Reply to this

Re: Science and the Environment

The number of people remaining at the end of the century will probably be a billion or less.

Brave of Lovelock to make such a prediction. If there’s one area where forecasts have proved dreadfully wrong it’s the population the Earth can sustain, as Ehrlich’s guess shows.

You’d think that into that prediction would have to come estimates of social and scientific-technological change, which, as Popper stressed so forcefully in The Poverty of Historicism, are beyond us.

But even at the level of climate I’m amazed at people’s confidence. Isn’t there something to the viewpoint of Tennekes?

But maybe the function of these predictions is not so much accuracy as to jolt us into action.

Posted by: David Corfield on January 29, 2009 4:58 PM | Permalink | Reply to this

Re: Science and the Environment

David wrote:

Brave of Lovelock to make such a prediction.

Yes. Perhaps I should point out that I don’t feel any confidence concerning such predictions, which involve guessing things like how adaptable people are. I just thought it was worth noting.

But even at the level of climate I’m amazed at people’s confidence.

I think you need to consider the whole world community as a single system. On the one hand we have the scientists, who are perhaps overly confident that human-induced climate change will be a serious problem. On the other hand we have everyone else, who says “Maybe it’s not a problem — and even if it is, I can’t be bothered to do very much about it.”

So, it all balances out: as a species, we’re unlikely to take drastic action until it’s clear there’s a real problem. If by then it’s too late… well, then natural selection will do its thing, penalizing those who don’t find a way to survive.

Posted by: John Baez on January 29, 2009 5:31 PM | Permalink | Reply to this

Re: Science and the Environment

But even at the level of climate I’m amazed at people’s confidence. Isn’t there something to the viewpoint of Tennekes?

I can’t quite tell what that viewpoint is supposed to be, or what confidence you’re amazed by. Tennekes seems to be mostly criticizing the treatment of oceans in coupled atmosphere-ocean climate models. I have only an amateurish interest in this sort of thing, but it seems possible to me that this is something that should be improved if we’re to have detailed predictions of the effects of climate change on specific regions, for instance. But the broad-brush picture of the climate sensitivity to CO2 and accompanying dangers is independent of that sort of detailed modeling question, and we know empirically that the ocean CO2 sink is slowing.

So, I’m confused. Are we just supposed to be concerned that people are trying to make too-precise predictions (I wouldn’t be able to judge), or are you suggesting that people are overly confident about even the zeroth-order picture of climate change? I don’t see how the latter claim could possibly be justified.

Posted by: Matt Reece on January 30, 2009 2:15 AM | Permalink | Reply to this

Re: Science and the Environment

Isn’t Tennekes casting doubt on the kind of modelling which produces estimates of climate sensitivities of 1.5-4°C for a doubled level of CO 2CO_2.

From my perspective it is not a little bit alarming that the current generation of climate models cannot simulate such fundamental phenomena as the Pacific Decadal Oscillation. I will not trust any climate model until and unless it can accurately represent the PDO and other slow features of the world ocean circulation.

But what do I know?

Posted by: David Corfield on January 30, 2009 9:02 AM | Permalink | Reply to this

Re: Science and the Environment

Isn’t Tennekes casting doubt on the kind of modelling which produces estimates of climate sensitivities of 1.5-4°C for a doubled level of CO 2.

But those estimates of climate sensitivities are consistent with empirical data (e.g. paleoclimate reconstructions). The field doesn’t rest solely on the accuracy of models.

Posted by: Matt Reece on January 30, 2009 2:44 PM | Permalink | Reply to this

Re: Science and the Environment

I’m not the most expert in atmosphere-ocean dynamics, but in my opinion, an ability to get the PDO completely right isn’t perhaps the most important thing to backing out a climate sensitivity estimate. This is for a couple of reasons:

(1) If you’re calculating climate sensitivity from a model, climate sensitivity is the model’s equilibrium response, and is probably not that sensitive to transient oscillatory behavior like the PDO.

(2) On the other hand, if you’re inferring climate sensitivity from observations, then the transient response does matter. However, if you’re inferring it from observations your model is probably too crude to have a PDO in it anyway, which leads to the more important point: the largest ocean influence on climate sensitivity estimates is not PDO dynamics, but the general rate of heat uptake into the ocean. That’s controlled mostly by vertical diffusion (and sub-grid scale eddy mixing and such which is parameterized by diffusion), not by the PDO. GCMs get overall heat uptake pretty well, although there is of course inter-model uncertainty in the transient response.

(3) If you do happen to think that the PDO is important to model-based climate sensitivity estimates, note that AOGCMs do have PDO-type behavior in them, although I don’t think any of them get the full PDO spectrum right. If you’re talking about the ability of the models to reproduce historical PDO data or to predict the future PDO, the main problem is perhaps not so much in their PDO dynamics, but that they can’t predict what phase of the PDO we’re in. That’s because you have to initialize them with the right ocean state, which is hard to infer from limited observations. Frequently it’s not even inferred at all; they just spin the models up from some state and use the final “equilibrium” state as the initial conditions for the real transient runs.

As a consequence, what the models give is not a skillful prediction of PDO behavior, but more like an average of different PDO behavior in different phases (if you average over initial conditions). That introduces a wider range of variability into projections (since you have to add uncertainty in, e.g., PDO phase), but arguably doesn’t really bias the long-term average climate state. This paper is an example of recent attempts to improve shorter-term ocean state predictions by using more accurate (i.e., observationally assimilated) initializations.

Posted by: Nathan Urban on January 30, 2009 11:27 PM | Permalink | Reply to this

Re: Science and the Environment

David C wrote “But maybe the function of these predictions is not so much accuracy as to jolt us into action.”

I think you meant to write “guaranateed accuracy” in the sentence above: AIUI you don’t think there’s any reason to believe the prediction is per se any more inaccurate than any other but rather that saying that anything can be predicted with any reasonable confidence at this point is the problem.

As I hinted at in a previous comment, you seem to want to analyse this as an issue purely of “scientific correctness”, rather than using a combined decision theoretic set of considerations. I suspect that the prediction is not so much “to jolt us into action” from a “shock-value” point of view but more from the ponit of view that “This is a reasonable prediciton given the current scientific knowledge. (Implicitly acknowledging there may be other predictions which have equally good foundations on current knowledge.) Taking note of this uncertainty, should we consider taking action on the basis of this possibility?” (Granted I might be projecting my viewpoint onto him.) Maybe he could include some explicit degree of confidence and variance in his statements, but it looks like a general journalist interview.

(It’s one of the side-effects of working on computer vision and robotics that one becomes painfully aware that taking no action is as much a deliberate choice as doing something new.)

Posted by: bane on January 30, 2009 10:39 AM | Permalink | Reply to this

Re: Science and the Environment

I see your point, but the decision situation is an order or two more complicated than your robot deciding whether or not to move. The situation of making a decision to embark on a protracted course of action (including do nothing) on the basis of conflicting estimates, factoring in estimates of the degree of dependency between expert advice, and whether they are overstating their confidence, and with very uncertain knowledge as to the likely effects of the action, and the likely effects of taking the action on other people in a position to make similar decisions, is a recipe for inaction.

Perhaps it’s something like robot football with unreliable sensors and motors.

Posted by: David Corfield on January 30, 2009 11:32 AM | Permalink | Reply to this

Re: Science and the Environment

Actually odometry is amazingly unreliable and sensors tend to be unreliable in the sense that you don’t know particularly well where they’re pointing so it’s unclear “where you’re repsonse is actually a response to”. The more salient point is just that, even if you’ve got a very highly uncertain estimate of where you, deciding to just keeping on doing whatever you’re currently doing (say, moving backward or standing still) since you aren’t that confident about what the “proper action” is, is a likely to get you in to trouble (getting caught on a floor grill, or sitting in the middle of a doorway so a human being falls over you) as taking some specific action based on your current model, and all these actions are influence at least as much by how much good/damage they could cause given your vague idea as by your view on how accurate your estimate is.

But I wasn’t criticising either your conclusions, your view on how (unlikely to be) accurate a particular model is likely to be or that the problem isn’t difficult, but more reflecting with interest in your methodology referring only to within a “scientific” valuation. Clearly there is something non-trivial here: I tend to think there’s enough science suggesting AGW could be happening along with sufficient consequences that my methodology suggests to do something in case it is, but I don’t think an invasion of genocidal zombie bunnies from mars next Monday has been ruled out with complete certainty but I’m not arguing for preparations for that possibility.

Posted by: bane on January 30, 2009 4:07 PM | Permalink | Reply to this

Re: Science and the Environment

Politically, the complexity of the decision problem may be a recipe for inaction. But decision-theoretically, I don’t think you can justify inaction on the mere basis of uncertainty. Uncertainty in the climate decision problem frequently tilts policy towards action, as the consequences of underestimating climate change and doing nothing tend to be worse than overestimating it and doing something. This is a combination of the long tail of climate sensitivity I mentioned earlier (it’s harder to rule out bad outcomes on physical/observational grounds than good outcomes), and that damages likely to rise faster than linearly with the magnitude and rate of climate change.

In particular, if you symmetrically inflate the variance of existing estimates to factor in unaccounted-for uncertainties, you’re not really going to strengthen the case for inaction. To strengthen the case for inaction you have to substantially raise the probability of low outcomes without raising the probability of high outcomes. You can only justify that if you have strong evidence that current estimates are overestimates, and not underestimates.

In other words, you have to be pretty certain that the outcomes and damages are benign before you can justify a policy of inaction. If you’re uncertain, then some amount of risk insurance is more reasonable.

Alternatively, if you’re not certain now but still want to justify inaction, you have to be pretty sure that our certainty about the problem will increase a lot in the near future. (And that it will increase in the direction of benign outcomes!) But historically that doesn’t appear to be the case. The modern range of climate sensitivity estimates isn’t any smaller than it was 30+ years ago. While model physics is improving, so is system complexity, which introduces additional uncertainty. The two seem to have been cancelling each other out for some time.

Nordhaus’s new book is a good overview of the economic cost-benefit analysis, which includes some discussion of how uncertainty affects optimal policy. There is by now a pretty large literature on uncertainty and learning in climate policy cost-benefit analysis. Most climate economists find that complete inaction is a relatively poor policy under a rather wide range of assumptions. Although they disagree on how much action is necessary, I’m not aware of any serious analysis which finds total inaction to be optimal in the presence of uncertainty. (Some, like Lomborg, justify inaction by ignoring uncertainty and picking relatively benign point estimates.) In extreme cases the tail-area risks can dominate the decision analysis, e.g. in Weitzman’s “dismal theorem” work. (I personally don’t think his treatment of uncertainty in that paper is valid, and so he’s too pessimistic, but the importance of tail-area risk remains.)

Posted by: Nathan Urban on January 30, 2009 11:58 PM | Permalink | Reply to this

Re: Science and the Environment

Even if there is uncertainty as to the extent to which carbon dioxide is altering global temperatures, it is certain that the oceans are rapidly acidifying due to dissolved carbon dioxide, and this change in acidity can have profound effects on ocean life, according to an article in the New York Times today entitled “Rising Acidity Is Threatening Food Web of Oceans, Science Panel Says.”

Posted by: Richard on January 31, 2009 10:12 PM | Permalink | Reply to this

Re: Science and the Environment

Yes, acidification is a real threat to ocean ecosystems, and that doesn’t get enough press relative to its risk. Ocean pH changes from CO2 are, as you say, much more predictable than climate changes.

Unfortunately the impacts on ecosystems are still poorly understood, but everything I’ve read points to bad news for calcifying organisms (corals and shellfish) and anything that depends on them.

Even under moderate climate change, ocean acidification has the potential to wipe out many (most?) coral reefs, including the Great Barrier Reef. (Even when the coral organisms themselves survive, the calcified reefs they build may not.) This obviously has implications for the food chain in areas near reefs. I don’t know as much about what the threat is to shellfish. But when you couple in existing anthropogenic stresses on ocean ecosystems (overfishing, pollution, etc.), it worries me a lot.

Posted by: Nathan Urban on February 1, 2009 2:22 PM | Permalink | Reply to this

Gregory Benford et al on Carbon Sequestration; Re: Science and the Environment

There’s a wonderful paper coauthored by one of our favorite hard Science Fiction authors, who is quite a fine Astrophysicist and biosciences entrepreneur:

Stuart E. Strand and Gregory Benford. Ocean Sequestration of Crop Residue Carbon: Recycling Fossil Fuel Carbon Back to Deep Sediments. Environmental Science and Technology, Online Jan. 12

Posted by: Jonathan Vos Post on January 30, 2009 7:02 AM | Permalink | Reply to this

Gregory Benford et al on Carbon Sequestration; Re: Science and the Environment

There’s a wonderful paper coauthored by one of our favorite hard Science Fiction authors, who is quite a fine Astrophysicist and biosciences entrepreneur:

Stuart E. Strand and Gregory Benford. Ocean Sequestration of Crop Residue Carbon: Recycling Fossil Fuel Carbon Back to Deep Sediments. Environmental Science and Technology, Online Jan. 12

Posted by: Jonathan Vos Post on January 30, 2009 7:02 AM | Permalink | Reply to this

Re: Science and the Environment

stepping backwards

Posted by: Rose on February 5, 2009 9:59 AM | Permalink | Reply to this

Morlot et al in PNAS: small warming more dangerous than previously assessed; Re: Science and the Environment

Joel B. Smith, Stephen H. Schneider, Michael Oppenheimer, Gary W. Yohe, William Hare, Michael D. Mastrandrea, Anand Patwardhan, Ian Burton, Jan Corfee-Morlot, Chris H. D. Magadza, Hans-Martin Füssel, A. Barrie Pittock, Atiq Rahman, Avelino Suarez, and Jean-Pascal van Ypersele. Assessing dangerous climate change through an update of the Intergovernmental Panel on Climate Change (IPCC) “reasons for concern”. Proceedings of the National Academy of Sciences, 2009; DOI: 10.1073/pnas.0812355106

Posted by: Jonathan Vos Post on March 2, 2009 1:14 AM | Permalink | Reply to this

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