Today, when asked whether he would see Gore’s new movie, Bush said, "doubt it." I doubt it too. Who needs truth when you’ve got truthiness?

But Bush also said something more insidious:

… in my judgment, we need to set aside whether or not greenhouse gases have been caused by mankind or because of natural effects, and focus on the technologies that will enable us to live better lives and, at the same time, protect the environment.

Should we "set aside" the question of whether human activity is driving climate change? I think not.

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A while back, I wrote a post on this subject. I never put it up — I was thinking of making it into an op-ed or something, but I never got around to it. Anyway, it’s relevant to this question. So I’ve put it below the fold.

I’m half-convinced that the latest from Nordhaus and Shellenberger is an April Fools joke. But OK, I’ll take it seriously.

Consider the three following positions, propounded primarily by right-wingers in recent years:

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  1. The atmosphere is not warming.
  2. The atmosphere is warming, but it’s part of a natural cycle, not attributable to human activity.
  3. The atmosphere is warming, and it’s attributable to human activity, but the "cure" (substantial CO2 emissions cuts) would be worse than the disease. It would be easier, and cost less, simply to adapt to a warmer world.

You wouldn’t know it from the amount of time environmentalists spend bashing #1, but very few people hold that position any more. Old-school, unreconstructed climate contrarianism is a dwindling fringe position at this point.

More common are #2 and #3, and you frequently see ‘wingers dancing back and forth between them, sometimes in the course of a single argument. Apparently Bush himself is a #2 (I also recommend Matthew Nisbet’s amusing account of George Will’s dimwittery).

It’s easy enough to knock down #2 with science — matter of fact, the folks at RealClimate just did so.

But as I’ve mentioned before, #3 is considerably trickier. It’s extremely difficult, verging on impossible, to pin down the global cost of substantially cutting back emissions. The number of factors and forces in play is effectively infinite. It is to the great benefit of entrenched industries and their ideological footsoldiers to exaggerate it as much as possible (Will, for example, tosses around the figure of $1 trillion; Steve Hayward casually mentioned $37 trillion). My general sense is that when all the costs and benefits are factored in, the effect will be a net positive. But that’s as much faith as argument. I doubt we’ll know until we’re well underway.

So given the uncertainty around costs, what’s wrong with #3? The answer is fairly simple: Climate warming is not a linear, predictable process. It’s better described as climate volatility. Once we "adapt" to the new climate we have in 2040, the changes will keep coming. We’ll have to adapt all over again to the climate of 2060, and the climate of 2080, etc. Human society, no matter how clever, no matter how wealthy, simply isn’t equipped to live in a constantly, dramatically changing climatic situation. Economic development depends on stability and predictability.

The changes we’re seeing now were put into motion 30-40 years ago. The CO2 we’re pumping into the atmosphere now will manifest in changes 30-40 years from now. Already we’ve insured climatic instability for at least that long, probably much longer, and we can only hope those changes won’t be sudden and catastrophic (so-called "tipping-point" changes).

It is, therefore, vitally important that #3 get publicly and definitively batted down. It’s incredibly dangerous. If we don’t want to cast humanity into a situation of permanent, chaotic instability, we need to stop accelerating climatic changes. If we don’t, we won’t simply "adapt." We’ll be constantly adapting, at immense, crippling cost. We may survive, but we sure as hell won’t flourish.

So while there is an element of good sense in Nordhaus and Shellenberger’s op-ed — we really do need to assess whether we’re prepared for climate changes that are already inevitable (though the idea of a single federal act mandating such assessment is more smugly clever than realistic) — the notion that we should simply give up arguing about the causes of global warming and the relative costs of adaptation vs. mitigation is perilous nonsense.

The public needs to digest the reality of climate change, the specter of permanent macro- and micro-instability, fully. We need to commit unreservedly to halting our acceleration of that instability. We all need to be pulling in the same direction, and that won’t happen until arguments like #3 die a richly deserved death.