[Vision2020] Climate Science: Introduction to Feedbacks: 150 Responses "...exactly the right level for interested laymen."

[Paul Rumelhart]

Understanding feedback in climate science is essential not just for 
laypersons but for climate scientists as well.  It's really the crux of 
the whole debate. No feedbacks, or balanced positive and negative 
feedbacks, mean warming of about 1.2C for a doubling of CO2 from 
pre-industrial levels.  Not much to worry about, it might even be 
beneficial to humanity.  Negative feedbacks reduce this value down from 
1.2C to even less warming.  So the whole meat of global warming comes 
down to positive feedbacks.  How strong are they?  Are they strong 
enough to overcome the negative feedbacks?  Etc.

The climate models, whose results have driven the fears of climate 
change, have always assumed positive feedbacks.  They just differ on how 
large of a magnitude those values will have.  Too large, and you get 
into "tipping point" territory.

Simply identifying all of the possible feedbacks is difficult, let alone 
modeling them.  Feedbacks can cause other feedbacks, positive or 
negative, in a cascade of secondary effects.  Granted, modeling the 
behavior of what is basically the prototype for complex systems is 
difficult.  Which is why I've always wondered why they are so sure the 
end result is catastrophic.

It seems odd to me that more work wasn't done early on regarding 
feedbacks, since they are so critical to the question at hand.  Lately, 
there has been some work done on feedbacks, some of which aren't modeled 
by current climate models.

For example, here is a news report about two papers that give some more 
data on two separate feedbacks which aren't currently modeled.  One 
would tend to increase the positive feedbacks from the models, the other 
would tend to decrease them:

http://www.chron.com/disp/story.mpl/nation/6841153.html

My gut feeling is that since in the past CO2 levels have been much 
higher than they are now and the system didn't end up with boiling 
oceans or a snowball earth, that the idea of tipping points and runaway 
feedbacks is a fantasy.  That doesn't mean that smaller positive 
feedbacks won't be catastrophic, but at least the worries about the 
climate snowballing out of control seem unfounded.  Maybe in a couple of 
decades we'll have been able to model things much more closely and will 
be able to pin the numbers down much better.  Until then, I'd rather we 
worked on reducing gasoline consumption because of pollution and 
geo-political concerns, and ramping up nuclear energy to reduce the need 
for coal.

Paul

Ted Moffett wrote:
> Some people will argue that climate science is too complex and 
> specialized for an educated layperson to comprehend, so the subject 
> should be left to those with PhD level knowledge. 
>  
> Of course, such an argument, when applied broadly, is a major blow to 
> the democratic principle that an educated public can make informed 
> choices at the ballot box regarding the positions politicians assume 
> on domestic economics, education, international politics and war, 
> gender, "race" and sexual orientation equality, freedom of religion, 
> and so forth; and any scientific issue that effects the public: stem 
> cell research, genetic engineering of plants, animals or perhaps human 
> beings, the safety or not of new IV Gen. fast nuclear reactors, the 
> brain development of a human fetus regarding how this impacts the 
> ethics of abortion, whether anthropogenic climate warming has a high 
> probability of being a significant problem in the future, and so forth.
>  
> If a layperson, meaning someone who is well educated but not at the 
> PhD level on a given issue, cannot conduct an informed broad survey of 
> expert opinion, to arrive at a rational objective assessment of the 
> likelihood of there being a consensus view, then perhaps society 
> should be managed by committees of PHd level experts, not by elected 
> politicians, given many politicians and the public at large simply 
> cannot comprehend highly technical problems sufficiently enough to 
> make rational informed decisions.  Perhaps this argument has some 
> similarities to the argument of Plato in the "Republic" ( 
> http://faculty.frostburg.edu/phil/forum/PlatoRep.htm : "This rule by 
> society’s best minds is the core concept of Plato’s so-called 
> “philosopher kings.” )
>  
> Committees composed of PHds in ethics, law, religion, economics, 
> international politics, military strategy, education, numerous 
> specialized scientific fields, and so forth, would make the important 
> decisions governing society for us... Perhaps in some sense this is 
> happening now, given the US Congress', and the 
> US public's, manipulation by powerful economic and political interests.
>  
> Regardless of the truth of this admittedly thorny question, I assume 
> that, given the possible planetary altering magnitude of anthropogenic 
> climate warming, for centuries and potentially millennia, that will 
> profoundly impact the US, it behoves every citizen, every voter, to 
> educate themselves as much as possible regarding the climate science 
> involved, because the problem boils down to whether the science is 
> reliable or not.  Anthropogenic climate warming is not similar to many 
> other pollution or industrial development problems, where we can 
> pollute or impact an ecosystem with future plans to realistically 
> recover the ecosystem.  Once powerful climate feedbacks begin to 
> accelerate impacting global climate (albedo reduction from ice loss, 
> ocean warming and carbon sink reversal, etc.) the problem is likely to 
> be significantly out of humanity's control, unless by extreme and 
> untested geo-engineering.  There is no compromise or negotiation with 
> the physics of Earth's climate system. 
>  
> Regardless of how emotionally politicized this issue has become 
> (rather irrationally political, it seems), it is fundamentally a 
> scientific question, that should be resolved first, if possible, 
> before assuming that strong action is indicated to address the 
> problem, involving economics, technology, lifestyle and the 
> political arena.
>  
> The following scientific presentation on climate feedbacks can perhaps 
> be understood by an educated layperson:
>  
> Introduction to feedbacks
>  
> http://www.realclimate.org/index.php/archives/2010/09/introduction-to-feedbacks/#more-4993
> ------------------------------------------
> Vision2020 Post: Ted Moffett
> ------------------------------------------------------------------------
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