Saturday, January 18, 2020

Certainties and Uncertainties in our Energy and Climate Futures: Steve Koonin



This is a recent (2019) talk which gives a good overview of current climate science. Speaker is Steve Koonin, formerly Undersecretary for Science, US Department of Energy (Obama administration), Caltech Provost and theoretical physicist.

See earlier post Epistemic Caution and Climate Change (including comments).

My own views (consistent, as far as I can tell, with what Steve says in the talk):
1. Evidence for recent warming (~1 degree C) is strong.

2. There exist previous eras of natural (non-anthropogenic) global temperature change of similar magnitude to what is happening now.

3. However, it is plausible that at least part of the recent temperature rise is due to increase of atmospheric CO2 due to human activity.

4. Climate models still have significant uncertainties. While the direct effect of CO2 IR absorption is well understood, second order effects like clouds, distribution of water vapor in the atmosphere, etc. are not under good control. The increase in temperature from a doubling of atmospheric CO2 is still uncertain to a factor of 2-3 and at the low range (e.g., 1.5 degree C) is not catastrophic. The direct effect of CO2 absorption is modest and at the low range (~1 degree C) of current consensus model predictions. Potentially catastrophic outcomes are due to second order effects that are not under good theoretical or computational control.

5. Even if a catastrophic outcome is only a low probability tail risk, it is prudent to explore technologies that reduce greenhouse gas production.

6. A Red Team exercise, properly done, would clarify what is certain and uncertain in climate science.

Simply stating these views can get you attacked by crazy people.
Please tell me what is implausible about the following scenario: IPCC latest report has as its central projection a ~1.5 degree C warming over the next decades, assuming CO2 production continues at current levels. During those decades, battery technology could improve by an order of magnitude, due to intense R&D efforts. Solar energy cost and efficiency could also improve significantly over the same period. If these technological advances are realized by, e.g., 2040, we could substantially decrease our carbon footprint without wholesale dislocation of the world economy. It seems that huge R&D investment (nevertheless totally negligible relative to GDP or, e.g., military spending) in alternative energy and storage technologies is a no brainer...

Koonin rebuts some criticisms of his talk.

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