Saturday, July 10, 2010

What I think about global warming

I've stolen the headline and most of "my" thoughts on the issue from a good post by William that people should read.  But enough with the praise, let's focus on the smaller points where I might disagree.

William writes:
The main points that most would agree on as "the consensus" are:

1. The earth is getting warmer (0.6 +/- 0.2 oC in the past century; 0.1 0.17 oC/decade over the last 30 years (see update)) [ch 2]
2. People are causing this [ch 12] (see update)
3. If GHG emissions continue, the warming will continue and indeed accelerate [ch 9]
4. (This will be a problem and we ought to do something about it)
I've put those four points in rough order of certainty. The last one is in brackets because whilst many would agree, many others (who agree with 1-3) would not, at least without qualification. It's probably not a part of the core consensus in the way 1-3 are.

Yep, all of that remains pretty well true, and remains the core....In the years since I wrote that nothing has come along to overturn any of that, and much has come in to buttress it....However, I still think there is room for honest skepticism and disagreement about point 4.... The real argument should be about point 4: that it will be a problem and we should do something about it....I don't know the answer to point 4, and I know that I don't know :-). 
So let's stop there for a moment.  I think it's better to split point 4 into:
4.a.  This will be a problem.
4.b. (We ought do something about it).
I don't think it's reasonable for anyone to acknowledge point 3, especially acceleration, and deny 4.a.  Even in the imaginary world where benefits in some areas outweigh the problems in others, there are still problems.  And virtually no one really believes in that imaginary world - if we could wave a Pielkean magic wand, a technology that cheaply and safely scrubs all GHG emissions from the atmosphere, any reasonable person given a yes or no choice on waving that wand would do it.
As for 4.b., I'll just note that it's not an exclusively scientific question - engineers, economists, and wonderful wonderful lawyers all play a part, not to mention the general public that pays the bill one way or another.  No wonder it's a squishier issue.
Also on 4.b., I think if we drop two unstated assumptions in much of the climate discussion - first, that the universe ends in the year 2100, and second, new GHG emissions will magically cease the moment we hit 2x present CO2 equivalent levels - then we know the answer.  Maybe someone could argue we still have a decade or so of playtime available before doing something about the problem but that would both be unwise and not relevant to 4.b.
Finally, I may not know anything more about ocean acidification than William notes in original post (probably less), but it's really a separate scientific consensus issue that doesn't even depend on climate change being real.  My amateur opinion is that acidification consensus is as solid as the climate consensus through its own version of 4.a., and on policy matters the issue pushes for the same policy solutions as climate change other than some geoengineering and ocean sequestration proposals, and possibly on a slightly longer timeframe.

UPDATE:  I continue to think, without much evidence to back it up, that the biggest human cost from GHGs will be malnutritrion-related deaths in areas of subsistence agriculture and fishing due to precipitation shifts and acidification.  Not necessarily an increase against the present baseline but an increase against a future baseline where the world aggressively reduces GHGs.


  1. You are too kind. I'll come back, but just quickly:

    > first, that the universe ends in the year 2100

    I agree that there are various things waiting past 2100 that it is hard to see as benevolent: several m of SLR from Greenalnd, for example. BUT the killer counter-argument (IMO) is that trying to predict society more than 100 years ahead is just too difficult. Had our ancestors of 100 years back looked ahead and tried to avoid what they saw as their pressing troubles - would we have thanked them? I am doubtful.

  2. Interesting thought experiment, William. I'm guessing they'd try to avoid mechanized warfare, which would've been good. Some would try to avoid the problems created by capitalism (mixed bag) while others would try to avoid socialist revolution (mixed bag). Many would try to avoid racial and ethnic mixing, which would've been bad, except that they actually tried that with extreme effort anyway.

    The wilderness conservation and public health movements were both off and running in the US 100 years ago, so combine them and you have a facsimile of the modern enviro issues. I don't know much about those fields in Europe.

    And maybe it's not entirely quibbling to point out that 2100 is less than 90 years from now.

  3. 100 years ago the most obviously pressing problem New York City was horse manure and carting away dead horses. (The first model year for the Model T Ford was 1909). By 2100 we will have new problems and new tools for dealing with both current and future problems that we can barely imagine today.

    Item 3 has a missing caveat "...relative to what the temperature would otherwise be". So one basis on which to agree with 3 and doubt 4a would be to believe that CO2-caused warming is likely to help stave off the next ice age. It also doesn't take much techno-optimism to figure that *by the time warming seems like a problem* we'll have better tools for dealing with it than we do now, so we should wait until then to solve it. Maybe this will be just like the horse manure issue - obviated by technological changes we want for other reasons.


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