Friday, June 09, 2006

Pascal's Wager and the prospect of hell

I have neglected my blog lately, and I confess that I have enjoyed doing so. For several days I have hardly read the political blogs and the news media, except to notice, on the occasion of the death of Abu Musab al-Zarqawi, the reassertion of our peculiar national personalization of war. If you'll remember when we invaded Iraq, our leaders and the media hardly ever said we were at war with Iraq, but rather that we were engaged in a struggle with "Saddam." Naturally it became very important to kill or capture Saddam Hussein, though our failure to do so expeditiously didn't keep the President from declaring Mission Accomplished from the deck of an anchored stageprop aircraft carrier. Six months later, a new round of triumphalist rhetoric was set off when a gratifyingly bearded, disheveled and disoriented Saddam Hussein was removed from his hideout, which, strangely was almost uniformly called a "spider hole" by the media. What was that about?

Anyway, Mission Accomplished II didn't seem to have been any more of a keeper than Mission Accomplished I. And now we have this gruesome display of Zarqawi's corpse, a sort of trophy, I guess, but I think this time that it's going to be sold as Turning the Corner, or Light at the End of the Tunnel, rather than Mission Accomplished III--if they have learned anything from the unravelling of MA1 and II.

But I digress. What I was going to say was that we might have another look at Pascal's Wager.

I never took Pascal's wager very seriously. I have always thought it was a philosophical absurdity. But that's because I am a reality-oriented person, and I see no tangible evidence that I am any more likely to be penalized by a Deity with anger-management problems for not believing in Him, than I am by malignant ghosts if I show insufficient respect to them when walking past a graveyard. (There are more sophisticated philosophical criticisms of Pascal's Wager than this, but clearly no sane Buddhist, much less a sane secular person, is going to accept Pascal's Wager if it's about dangerous ghosts. Same with wrathful deities, in my book. )

But there is a version of Pascal's Wager that makes a lot of sense. And climate change provides us with that version. Imagine an unknown chance of civilization being destroyed if we do nothing. We don't know the magnitude of the risk, but we do know, and can verify--unlike the stuff about malign Spirits--that known causes, operating today, can lead to civilization being chaotically disrupted unless unless some intervention occurs to save us from such chaos.

I am talking about global warming.

That is, many of the CO2-driven climate changes predicted by current computer modeling would, if they occurred, lead to widespread temperate-zone desertification, famine, wars over remaining water and arable land, and the creation of vast throngs of desperate refugees displaced by rising sea levels, or hunger, or violence, or disease.

There are reasonable actions that could prevent some or all of the potential climate changes from happening. These actions might be inconvenient. On the other hand, will you risk the continuance of a livable world on the basis of a belief that mechanisms as yet unknown will fortuitously save us?

We do know, absolutely, that if you pump greenhouse gases into the atmosphere that the atmosphere will get warmer. The laws of physics require it. We know it for the same reasons we know if you park your car in the sun with the windows up it will get hot inside. The physics is established and beyond dispute.

You can prevent your car from getting hot inside in about 3 ways. You can open the windows. You can turn on the engine and run the air conditioner. Or you can cover the windows (and the top of the car) with a reflective shade.

Opening the windows is equivalent (depending on when you do it) to either not putting excess CO2 in the atmosphere in the first place, or to sequestering the CO2 if you have already had some greenhouse warming. Running the AC is equivalent to an ice age starting up, assuming that it could happen on our command. Reflective shade is equivalent to increasing the cloud cover, to keep the solar heating out of the atmosphere sufficiently to nullify the CO2 forcing.

The global warming denialists either have to assume that there is a loophole in the laws of physics to exempt our atmosphere from greenhouse effects, or that the not entirely understood forcings that have created previous ice ages will fortuitously begin to operate just as we need them, canceling out the CO2. (Of course you never know--we could be plunged all the way back to full-glacial conditions, rather than just balancing the CO2 exactly. That's the problem with relying on chance or magic.)

Another chance-or-magic scenario is to assume that natural feedback mechanisms, presently unknown, will sequester the excess CO2.

Or, similarly, we can assume that the increased CO2 will, by mechanisms also presently unknown, increase the albedo to reflect enough sunlight that the increased CO2 will again be cancelled out.

All the global warming denial arguments seem to require that we ignore physics, or foreseeable risks, or common sense, or maybe all three. And if we do that we could easily end up in hell. I think I'm with Pascal here.

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