FAWS comments on Undiscriminating Skepticism - Less Wrong

97 Post author: Eliezer_Yudkowsky 14 March 2010 11:23PM

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Comment author: FAWS 15 March 2010 11:35:13AM *  7 points [-]

I'll bite the bullet and say global warming is the perfect example here. It's pretty clear to me that many people hold their positions on this issue - pro and contra - for political/social reasons rather than evidential ones.

There seems to be plenty of motivated arguing on both sides. But even though climate science is complicated the basic mechanism for CO2 raising temperatures is really simple and well supported by basic science. No one is disputing CO2's absorption spectrum (that I know of). It's possible that CO2 might not have any such effect on aggregate in a complicated system, but that would be quite remarkable and I don't think any mechanism has been proposed (other than that global warming is miraculously balancing out a coming ice age).

Comment author: BenAlbahari 15 March 2010 01:55:10PM *  2 points [-]

It's a good habit to avoid the Appeal To Ignorance of an opposing view.

  1. Some skeptics do actually dispute the absorption effect of CO2.
  2. The proposed mechanism by which CO2 does not cause overall warming is a negative feedback loop.

I actually agree with your conclusion, but here's the evidence you need to back up the specific cases you brought up:

Does atmospheric CO2 cause significant global warming?
Do negative feedback loops mostly cushion the effect of atmospheric CO2 increases?

Comment author: FAWS 15 March 2010 02:33:12PM *  3 points [-]

Some skeptics do actually dispute the absorption effect of CO2.

That is, they claim that the spectrum of CO2 has been faked? Or deny that there is such a thing as a spectrum?

The proposed mechanism by which CO2 does not cause overall warming is a negative feedback loop.

I was aware of feedback loop proposals, but they seem to amount to arguing for a weaker AGW effect rather than none. I tend to mentally file them under squabbling about the exact models rather than AGW denial. Are there any such proposed loops that would result in zero or effectively zero warming? ITSM that all feedback loops that involve actual warming as a step would not qualify because to result in effectively zero warming the effect would have to be strong enough to drown out temperature changes from all other causes unless overwhelmingly strong.

Comment author: BenAlbahari 15 March 2010 03:20:00PM *  3 points [-]

The leading skeptics (e.g. Roy Spencer) claim that negative feedback loops (due to clouds that reflect heat back into space) will reduce the warming effect of CO2 to be within the fluctuations Earth naturally experiences. So it's a serious denial, rather than a minor squabble. And the views of the opposing experts (also in the link I sent) strongly indicate Spencer and his colleagues are mistaken (one such reason is that without a positive feedback, it's very hard to explain the rapid shift in temperatures we know occurred between glacials and interglacials).

The skeptics who deny CO2 actually has an effect at all are fringe. The link I sent has the most qualified expert I could find (Gerhard Gerlich) who holds that view. Given that even the NIPCC (Non-Governmental International Panel on Climate Change) hasn't subscribed to this position, I disregard its importance.

The arguments and experts are all summarized here (it's a wiki, so you can add to it yourself if you find something new):
http://www.takeonit.com/question/5.aspx

Comment author: [deleted] 26 September 2011 06:01:56AM *  3 points [-]

The leading skeptics (e.g. Roy Spencer) claim that negative feedback loops (due to clouds that reflect heat > back into space) will reduce the warming effect of CO2 to be within the fluctuations Earth naturally experiences.

I don't know as I'd find that comforting, considering that the Cretaceous climate was within fluctuations the Earth naturally experiences, and transitioning to that in such a short time would still be a pretty darn significant systemic shock to economy and ecology alike...

EDIT: To be clear, I'm not saying we're headed for a new Cretaceous, just that "fluctuations the Earth naturally experiences" could still allow for some pretty steep gradients between the last century and any plausible, randomly-selected point within the known range.