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May 25, 2008

On climate change

Sometimes I'm haunted by the feeling that I'm studying the wrong things in life. That while networks, evolution and terrorism are interesting, they're only peripherally related to the central problems that face our generation. That is, sometimes I wish I worked on climate change and, in particular, on sustainable development and carbon-neutral energy sources (like solar cells). Fortunately, there are a lot of people working on this problem, and there's even a climate change summer school this year, run by the Mathematical Sciences Research Institute (MSRI) in Berkeley CA [1]. If you can't make the event, MSRI recently published an online book that gives a good introduction (in relatively accessible terms) to the science, called Mathematics of Climate Change.

It's hard, of course, to really get your head around how big a problem the energy-question is. We all know by now that we should use less oil, that we should buy more fuel efficient cars, that we should have better insulated houses, lower-power refrigerators, etc.; there are lots of shoulds floating around in the media. And then there are the sky-is-falling types, who say that if we don't do all these things immediately, then the planet is going to overheat, the oceans will rise 100 feet, and civilization will be cast 4000 years back to the Stone Age. Fear can be a powerful motivator, but only when it's clear what the right reaction is. Unfortunately, for an average person who wants to have a positive impact, to do their part in saving the world, it's not at all clear what can be done, or even how much urgency is really warranted.

Last week, Prof. Nathan Lewis (CalTech) visited SFI as our colloquium speaker. Lewis has been trying to get his head around just how big the problem of sustainable growth is, and then translate it into understandable terms. I wasn't that thrilled with the style of his presentation, but the content itself was great and the message was rather clear.

First, there's the question of what are the consequences of climate change. If the consequences are small, then maybe it's okay to ignore the whole problem. Unfortunately, the last time we know for a fact that carbon dioxide (CO2) levels were close to what they are approaching now, 90% of all life on the Earth became extinct. This catastrophe happened about 251.4 million years ago (for comparison, dinosaurs died out about 65.5 million years ago), and is called the end-Permian extinction event. To put it in more clear terms how big an extinction this was, it's the only time in all of Earth's history that cockroaches almost became extinct. This is not, of course, to say that 90% of all life on Earth (possibly including us) will become extinct over the next few centuries or millennia because of the increased (and increasing!) CO2 levels we're experiencing, but that we have very little experience with or expectation about what happens when CO2 levels are this high, and the only data point we do have (the end-Permian event) suggests that things could be very bad. So, it might be useful for us to try to avoid venturing into such unknown territory. We only have one planet to experiment with, after all.

So, if we're resolved to avoid end-Permian-like CO2 levels, what can we do? If you think that human-generated CO2 makes no significant contribution to the global CO2 levels, then you don't have many options that don't involve actively extracting CO2 from the atmosphere (e.g., planting lots and lots of trees). On the other hand, if you, like the vast (vast!) majority of climate scientists, think that human-generated CO2 is the main culprit of rising CO2 concentrations (and temperatures), then we have lots of options, since we theoretically have control over how much CO2 we as humans emit [2]. Unfortunately, one of Lewis's points is that, given the scale of the problem we face and how much time we have left to solve it, simply reducing CO2 output is not going to be enough. That is, being green enough to save the planet as we know it is going to require a major reallocation of our civilization's resources; business-as-usual, or even a half-assed attempt, is not going to make a big enough change in atmospheric CO2 concentrations to prevent the planet from being irrevocably changed (heated) for the next 3000 years or more.

To keep CO2 levels from approaching end-Permian levels, we basically have to eliminate almost all CO2 emissions from human industrial activities, everywhere on Earth, within the next 50 years. That's a huge task, especially considering that China recently became the world's largest emitter of CO2, and, along with the US, shows little interest in reducing its emissions. (Scare-tactics go both ways, and the usual argument against doing anything is that it will hurt hurt economic growth, cost jobs, etc. This is ridiculous, of course, since there are huge economic gains to be won by being successful at creating clean, abundant energy.)

Fortunately, there's a good solution at hand: solar energy. Unlike other sources (wind power, tidal power, geothermal power, biofuels, etc.), solar energy is incredibly abundant (1000 times more abundant than wind power), and could satisfy the energy demands of the entire planet using today's technology. Some estimates say that enough sunlight falls on the southeast quarter of New Mexico to power the entire United States. In fact, solar energy is so abundant that covering only something like 1% of the Earth's land with solar panels would give us plentiful power in perpetuity. And, as a bonus, solar power emits basically no carbon dioxide.

The hurdles to a solar-powered future are twofold (there are others, too, but these are the big ones). First, there are the political problem with getting all of civilization to embrace this solution now, rather than in 50 years when it's too late (that is, in 50 years, if we've done nothing significant, CO2 levels will already be at their end-Permian levels). The political climate does seem to be changing a little, but the inertia in the direction of ignoring the problem and burning our way back to the end-Permian is very very strong. The second problem is that energy from the sun is still a lot more expensive than energy from oil and coal, so there's not yet an economic incentive to get behind solar power. For the average citizen, then, there's not much to do that won't cost (possibly a lot) more money, and this severely limits the ability of the populace to use their economic leverage to drive the switch to solar power. This last part is where carbon taxes or a cap-and-trade system can change the balance, by making oil and coal more expensive relative to solar. If these systems can be put in place relatively soon, and the political climate continues to become more favorable to large-scale changes to where we get our energy and how we use it, we may be able to avoid end-Permian-level CO2 concentrations. Plus, if we solve the energy problem (and with it the CO2 problem), there are other important problems (e.g., water, food, etc.) that we will, in principle, also be able to solve. It's a bright future, if only we can find it in ourselves to collectively get there.

Update 27 May 2008: In the comments, "diarmuid" points out that David MacKay, a well known expert on learning algorithms, inference and information theory, comes to basically the same conclusions above about how to solve the energy-climate problem. MacKay has even written a book "Without Hot Air" about it, for those interested in more. (It looks like a draft of the book is available for free download.)

Update 29 May 2009: Bela Nagy tells me that there's another summer school on climate change, with the impressive-sounding name The International Graduate Summer School on Statistics and Climate Modeling. This one is being run at CU-Boulder by the National Center for Atmospheric Research (NCAR) and the Institute for Mathematics Applied to Geosciences (IMAGe). It runs August 9-13, and they'll be accepting applications up until June 15th. The organizers are Stephan Sain (NCAR), Doug Nychka (IMAGe, NCAR), Claudia Tebaldi (NCAR), Caspar Ammann (NCAR), and Bo Li (NCAR and Pudue).

Update 14 June 2008: Carl Zimmer, science writer and author of a number of best-selling popular science books, now also has an essay on the end-Permian extinction and its relationship to the current warming trend, which says much the same thing about the threat life on Earth faces from increased CO2 levels.

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[1] Climate Change Summer School July 14th - August 1st, 2008

Organized By: Chris Jones (UNC Chapel Hill), Inez Fung (U.C. Berkeley), Eric Kostelich (Arizona State University), K.K. Tung (U. Washington), and Mary Lou Zeeman (Bowdoin College).

[2] A nice paraphrasing of what the industrial revolution has done to the atmosphere is this: burning coal and oil in our factories and cars has had a similar effect on the atmosphere as if a massive volcano had been erupting continuously, with ever increasing ferocity, for 200 years or so.

posted May 25, 2008 09:24 AM in Global Warming | permalink

Comments

Posted by: Simmons at May 25, 2008 05:19 PM

Posted by: diarmuid at May 27, 2008 08:17 AM

Posted by: wanieda at May 28, 2008 11:17 PM

Posted by: Contrarian Profits at June 11, 2008 12:17 PM

Posted by: Mechanic at June 18, 2008 02:34 PM