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Thursday, July 19, 2007


What will be killing the people of the world?

[Updated and bumped to the top (newer posts below this one); see below]

Let's start with this, which is talked about in Al Gore's "An Inconvenient Truth," but this comes from an article (pdf) by Caltech Chemistry Professor Nathan Lewis in the latest issue of Engineering & Science magazine:

The melting of Greenland's ice pack has been much in the news, but let's talk instead about the melting of the permafrost. No climate model has that nonlinear effect built in, because we have no experience of it in human history. Permafrost is the (until now) permanently frozen soil of the tundra, and as the ice crystals in it melt, itreflects less light and turns darker, absorbing more light, and that melts more permafrost. Helium dating of trapped bubbles in the permafrost shows that we're melting permafrost now that hasn't been melted in 40,000 years. And there's enough CO2 and methane (another greenhouse gas) trapped in the permafrost to have the greenhouse gas levels not go up by a factor of two but by a factor of 10.

The world was there at least once before, most recently in the Permian era 250 million years ago. There was a massive release of isotopically light carbon from unknown causes, and CO2 levels rose by a factor of 10. (The fast release rate and the isotope ratio suggest it was some sort of self-catalyzing event, such as permafrost melting, as opposed to, say, a volcanic release.) Temperatures spiked for on the order of tens of thousands of years, and the fossil record shows that about 90 percent of the species on the planet went extinct.
Even capitalism hasn't caused the deaths of that many people...yet!

So, where are we going with this? Lewis' article is a lengthy exploration of energy sources, energy needs, and the CO2 production consequences of all of those. There are lots of calculations, estimates, and assumptions involved, and if this is a subject that interests you, read the article. Here are some excerpts:

Although major uncertainties remain, most climate-change researchers set 550 ppmv as the upper limit of what would lead to about a two degree- Centigrade mean global temperature rise. This is projected to have significant, but possibly not catastrophic, impacts on the earth's climate. For example, the coral reefs would probably all die. But we, as humans, would probably be able to adapt, at some level, to such a change. On the other hand, most people in the modeling effort feel that 750 ppmv or higher would be quite serious.

If we want to hold CO2 even to 550 ppmv, even with aggressive energy efficiency we will need as much clean, carbon-free energy within the next 40 years, online, as the entire oil, natural gas, coal, and nuclear industries today combined—10 to 15 terawatts. This is not changing a few lightbulbs in Fresno, this is building an industry comparable to 50 Exxon Mobils.
Many cynics on the left think Al Gore is just a secret shill for the nuclear power industry. Perhaps he is. Here's what Lewis says about nuclear:
We could go nuclear, which is the only proven technology that we have that could scale to these numbers. We have about 400 nuclear power plants in the world today. To get the 10 terawatts we need...we'd need 10,000 of our current one-gigawatt reactors, and that means we'd have to build one every other day somewhere in the world for the next 50 straight years.

There isn't enough terrestrial uranium on the planet to build them as once-through reactors. We could get enough uranium from seawater, if we processed the equivalent of 3,000 Niagara Falls 24/7 to do the extraction. Which means that the only credible nuclear-energy source today involves plutonium. That's never talked about by the politicians, but it's a fact...We'd need about 10,000 fast-breeder reactors and, by the way, their commissioned lifetime is only 50 years. That means that after we choose this route, we're building one of them every other day, or more rapidly, forever.
Lewis discusses the problems with carbon sequestration (I'll let you read that if you're interested), the limited potential of hydroelectric, geothermal, and wind (not that any of those should be ignored, no more than energy savings through efficiency, just that none of them are remotely enough to fully solve the problem), and ends with the promise of his own specialty, solar. According to him, just six 400 square kilometer (!) areas of photovoltaics, more or less one per continent, could supply enough energy to power the globe. But there are problems with that too, when it comes to converting the sunlight to hydrogen fuel (either for simple storage of the energy, or for use as a gasoline substitute for vehicles).

His conclusion is a bit depressing, but only because he's completely bound up in a capitalist economic model:

I haven't talked much about economics, but I will say that it's easy to prove, thinking 100 years out, on a risk-adjusted net-present-value basis, that the earth is simply not worth saving. It's a fully depreciated, four-billion-year-old asset.
I'm leaving out the slightly more optimistic part, where he posits that a solution may be possible. But, as he concludes:
I leave it to you to decide whether this is something that we cannot afford to do, or something at which we simply cannot afford to fail. Remember, we get to do this experiment exactly once. And that time, like it or not, is now.
Interesting (and vitally important) stuff.

Update: I'm reminded by something read elsewhere about a point I left out (there's a lot in this article). While the article does make clear that "individual solutions" (e.g., stop drinking water out of plastic bottles) won't solve the world's problems, they do make a difference, and there's one that isn't as widely recognized as some others - buying locally produced food, something that is more important (for the planet, anyway) than buying organic food:

In our highly mechanized western agricultural system, the energy embedded in food—to run the farm and grow the food and transport it to the supermarket and put it in the refrigerator—is 10 to 20 times the energy content of the food itself. And the farther you live from the food source, the more embedded energy you consume...This means that just keeping us fed requires one to two kilowatts.
Since each American uses an average of 10 kilowatts of energy, that means that a whopping 10-20% of the energy you consume (if you're an American) is used simply to transport your food to you. This is, as you may remember, one of the key lessons the Cubans learned, the story talked about in the movie "How Cuba Survived Peak Oil."

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