Left Behinds

The anti-andrewsullivan.com. Or, the Robin Hood (Maid Marian?) of bright pink Blogger blogs.

Wednesday, March 08, 2006

Why it matters to be rational, and how you can tell we aren’t, part II

In Part I I discussed avian flu as the near-term threat I think we're not taking seriously enough. Here I'm going to talk about global warming, the long-term threat.

I'll start with a doomsday scenario. It is not a particularly original one—I think it was the basis for this crappy movie—but I think it serves as a good way to illustrate why global warming is such a very severe worry.

I'm sure everyone knows the Gulf Stream, the warm ocean current that keeps the northeastern United States and the U.K. more temperate than their latitudes would predict. Well, the Gulf Stream is part of a worldwide system of ocean currents known as the Ocean Conveyor.

For a variety of reasons, North Atlantic waters are relatively salty compared with other parts of the world ocean. Salty water is denser than fresh water. Cold water is denser than warm water. When the warm, salty waters of the North Atlantic release heat to the atmosphere, they become colder and begin to sink.

In the seas that ring the northern fringe of the Atlantic—the Labrador, Irminger, and Greenland Seas—the ocean releases large amounts of heat to the atmosphere and then a great volume of cold, salty water sinks to the abyss. This water flows slowly at great depths into the South Atlantic and eventually throughout the world’s oceans.

Thus, the North Atlantic is the source of the deep limb of the Ocean Conveyor. The plunge of this great mass of cold, salty water propels the global ocean’s conveyor-like circulation system. It also helps draw warm, salty tropical surface waters northward to replace the sinking waters. This process is called “thermohaline circulation,” from the Greek words “thermos” (heat) and “halos” (salt).

If cold, salty North Atlantic waters did not sink, a primary force driving global ocean circulation could slacken and cease. Existing currents could weaken or be redirected. The resulting reorganization of the ocean’s circulation would reconfigure Earth’s climate patterns.

Computer models simulating ocean-atmosphere climate dynamics indicate that the North Atlantic region would cool 3° to 5° Celsius if Conveyor circulation were totally disrupted. It would produce winters twice as cold as the worst winters on record in the eastern United States in the past century. In addition, previous Conveyor shutdowns have been linked with widespread droughts throughout the globe.

It is crucial to remember two points: 1) If thermohaline circulation shuts down and induces a climate transition, severe winters in the North Atlantic region would likely persist for decades to centuries—until conditions reached another threshold at which thermohaline circulation might resume. 2) Abrupt regional cooling may occur even as the earth, on average, continues to warm.

Signs of a possible slowdown already exist. A 2001 report in Nature indicates that the flow of cold, dense water from the Norwegian and Greenland Seas into the North Atlantic has diminished by at least 20 percent since 1950.


So, less salty, cold, sinking water in the North Atlantic could totally fuck us. What could give us less salty water? How about a whole lot of freshwater ice going into the sea up there, say from the Greenland ice sheet?

The amount of ice flowing into the sea from large glaciers in southern Greenland has almost doubled in the last 10 years, possibly requiring scientists to increase estimates of how much the world's oceans could rise under the influence of global warming, according to a study being published today in the journal Science.

The study said there was evidence that the rise in flows would soon spread to glaciers farther north in Greenland, which is covered with an ancient ice sheet nearly two miles thick in places, and which holds enough water to raise global sea levels 20 feet or more should it all flow into the ocean.


But surely we would have time to adjust, right?

Fossil evidence clearly demonstrates that Earth's climate can shift gears within a decade, establishing new and different patterns that can persist for decades to centuries.


Right. Crap.

Of course, we don't know how close we are to this happening. If it happens in the next two decades, we're screwed. If it happens in a century, it could offset global warming for those of us in the northeast U.S., while mostly screwing more tropical people.

This shutdown of the Ocean Conveyor is only one of three major problems that could be triggered by global warming pretty soon.

There are three specific events that these scientists describe as especially worrisome and potentially imminent, although the time frames are a matter of dispute: widespread coral bleaching that could damage the world's fisheries within three decades; dramatic sea level rise by the end of the century that would take tens of thousands of years to reverse; and, within 200 years, a shutdown of the ocean current that moderates temperatures in northern Europe.

The debate has been intensifying because Earth is warming much faster than some researchers had predicted. James E. Hansen, who directs NASA's Goddard Institute of Space Studies, last week confirmed that 2005 was the warmest year on record, surpassing 1998. Earth's average temperature has risen nearly 1 degree Fahrenheit over the past 30 years, he noted, and another increase of about 4 degrees over the next century would "imply changes that constitute practically a different planet."

"It's not something you can adapt to," Hansen said in an interview. "We can't let it go on another 10 years like this. We've got to do something."


James Hansen has been trying to warn us about this for twenty years, incidentally. He was the first to brief Congress on the subject in the late 1980s, and has been a hero in overcoming a scientist's traditional reluctance to take dramatic public stands. He's gotten plenty of shit for it, too. A great American.

Princeton University geosciences and international affairs professor Michael Oppenheimer, who also advises the advocacy group Environmental Defense, said one of the greatest dangers lies in the disintegration of the Greenland or West Antarctic ice sheets, which together hold about 20 percent of the fresh water on the planet. If either of the two sheets disintegrates, sea level could rise nearly 20 feet in the course of a couple of centuries, swamping the southern third of Florida and Manhattan up to the middle of Greenwich Village.


Not two months after that article ran, this report hit the papers.

The Antarctic ice sheet is losing as much as 36 cubic miles of ice a year in a trend that scientists link to global warming, according to a new paper that provides the first evidence that the sheet's total mass is shrinking significantly.

It is one of a slew of scientific papers in recent weeks that have sought to gauge the impact of climate change on the world's oceans and lakes. Just last month two researchers reported that Greenland's glaciers are melting into the sea twice as fast as previously believed, and a separate paper in Science today predicts that by the end of this century lakes and streams on one-fourth of the African continent could be drying up because of higher temperatures.


(As long as we're on the subject of bad stuff happening because of global warming: polar bears are drowning because of melting ice, and beetles formerly held in check by cold winters are devastating the great northern forests. And a big hurricane destroyed one of our major cities.)

I am heartened that the problem is getting major attention in the media now. The problem is, it is getting virtually zero attention from either political party. That, in turn, is because politicians have quite correctly deduced that global warming motivates just about nobody's vote. (The Democrats, for example, seem to be pushing an energy plan made up of some combination of ethanol, a pander to Midwestern corn farmers, and liquefied coal, a pander to Western coal states. Usually the coal thing is accompanied by some sop to the idea of carbon sequestration, a technology that doesn't exist yet. It makes me want to throw things.)

Why don't voters care? I am sure SG can explain the phenomenon better than I can in terms of economic modeling of behavior, but let me try to compare terrorism (which has seriously motivated votes in at least the last few election cycles) to global warming (which hasn't). Terrorism is for the most part extremely unlikely, and probably (in an opinion I am pulling from my ass) September 11 will stand for a long time as its worst ever blow. But September 11's damage was obvious, instantaneous, and traumatic, and provoked fear of far greater harm that could come without warning. Global warming, on the other hand, is 100% likely (it is already underway), and if left unchecked its damage will almost certainly dwarf September 11. Yet even if the entire world's climate shifts over a decade, in human terms that change will still feel gradual, indirect, and to some extent manageable. A few hundred to a few thousand more people may die of heatstroke alone each year in this country with a relatively small rise in temperature—in other words a September 11 maybe every couple of years—but we will not take notice.

If we assessed our risks rationally, in other words, all deaths being equal, we would make global warming one of our top priorities. Because we don't, our president can drum up fear over the possibility of Iran getting nuclear arms, which is unlikely to be a serious existential problem for us anytime in the foreseeable future.

I would start proposing some solutions but a) this has already gone on far too long, and b) I think you'd do better to listen to better-informed people than me. Once we can get the technology working, I think our best medium-term bet for reducing our emissions may be pebble-bed nuclear plants. One better-informed plan can be found here. A well-informed critique of it can be found here, and another, general vision is here.


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UPDATE (July 11, 2006): We have since learned that nuclear is not a viable option. Basically, there just isn't enough rich uranium ore around.

7 Comments:

  • At 6:58 PM, Blogger Solomon Grundy said…

    Really, pebble-bed nuclear plants? That seems like the lowest medium-term risk, but over the very long term it is nearly certain that there would be a major ecological disaster at some point involving either waste or reactor problems. Nation states are too unstable (in a tiny historical blip, the mighty Soviet Empire became a collection of second-world countries, some on the verge of collapse, for instance) to guarantee maintenance, etc.

    That's my off the cuff reaction, at least.

    Very good point about the cold calculation of risk.

     
  • At 7:05 PM, Blogger Solomon Grundy said…

    And what about shipment of nuclear waste? I almost never play the war on terror card, but if New York, for instance, dealt with its nuclear waste anything like its garbage problem (which, politically, it probably would), there would be continual long-distance shipment of the waste. I agree that terror threats are much lower risks than global warming threats, but a national shift to nuclear energy would dramatically increase the terror risks. Don't you think? I'm kind of talking out of my ass.

     
  • At 7:08 PM, Blogger Solomon Grundy said…

    And even if what I just said isn't true, that's certainly how it would be spun politically.

    I don't really see nuclear power happening, politically. Too many interest groups opposed to it and too easy to spin negatively.

     
  • At 7:30 PM, Blogger Antid Oto said…

    Thi is actually another thing I was going to include in the original post, but it was running too long as it was: in terms of a balance of risk, nuclear power is clearly superior to coal. Yes, you have a buildup of radioactive waste, but with pebble-bed nuclear plants there really wouldn't be much chance for a major ecological catastrophe. A minor one, sure, if you spilled some waste somewhere, but definitely not a Chernobyl. It is risky to continually ship nuclear waste across the country, but we ship huge amounts of coal across the country constantly and seem to manage that ok.

    Mind you, these are all basically potential risks. We have not had a major nuclear accident in this country, though we had a big scare. We've not even particularly given people much cancer. I'm sure we would if we switched to nuclear, but we'd have fewer people dying in coal mines. Everything's a tradeoff.

    As far as nations becoming unstable: pebble-bed fuel requires significant technical savvy to make, and it takes even more technical savvy to process the spent fuel, mixed as it is with so much ceramic, into any kind of weapon. As a security threat from foreign nations it's very remote at worst. The worst we'd be looking at is some kind of low grade radiological bomb if a terrorist group got his hands on a pile of the stuff. Again, comparatively low risk.

    Keep in mind, too, that we have to consider this in a balance of possibilities, not in isolation. Do we want to keep using so much coal or even expand its use? How much can we conserve, realistically? Are we really going to build enough wind plants anytime soon to power a significant part of our economy (hint: no). What should we do instead? For a long time I agreed with you that nuclear power was too dangerous, but if it works pebble-bed technology gets rid of the catastrophic danger, and now I think global warming is far more of a problem.

    Finally, the fact that that's how it will be spun politically, using precisely those appeals to fear that you just mentioned--and that as a result we probably won't switch to nuclear power--is exactly what I was trying to talk about.

    Do you have any thoughts about the economic modeling of people's assessment of risk?

     
  • At 10:25 PM, Blogger Antid Oto said…

    I should add, though, that I'm no authority. I really do recommend you read those links providing other people's well-thought-through, comprehensive ideas. I just know we can't keep burning coal and oil, and nuclear isn't as bad as its image.

     
  • At 1:45 AM, Blogger Solomon Grundy said…

    I liked that last link (although, haven't the last 30 years involved a decline in standard of living for a huge number of people?).

    The Daily Kos plan I didn't understand. Why the hell was it written like a crappy political advertisement? I only skimmed through it.

    I'll get back to you about risk.

     
  • At 2:22 AM, Blogger Antid Oto said…

    It gets into more detailed policy later. You have to skip a lot up top. I didn't understand why it was written so crappily either, except that they seem to have attended to marketing before content, or along with content, and they're not marketing professionals so they did a very bad job. Also, they did it "open source," also known as "writing by committee," with predictable results.

     

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