American Presidential Choices: An Opinion Based on Climate Science - by James Hansen

Why has nature sucked up more CO2 than expected?  We suggested[3] that increased drawdown may be largely due to human fertilization of the biosphere, via excessive application of fugitive nitrogen fertilizers and the effect of excessive atmospheric CO2.  Depending on what the correct explanation is, this good news on the carbon cycle could mean that it may be possible to achieve drawdown of somewhat more than 100 GtC via global improvements in agricultural and forestry practices, including reforestation and better soil management.  These practices can be spurred via appropriate incentives in United Nations programs for climate adaptation and mitigation.

This moderate good news on the carbon cycle is offset by bad news on atmospheric methane (Fig. 2). Methane amount was stable from 1999 to 2006, but growth resumed in the past decade and accelerated more sharply in the past two years.  Although the reasons for resumed methane growth remain to be accurately quantified, the largest methane source is fossil fuel mining and leakage, and the United States seems to be the greatest contributor.[4]  The timing and location of renewed methane growth suggest hydraulic fracturing (“fracking”) of shale formations as the primary cause of methane growth.
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Finally, the relevance of climate and energy science to political campaigns: (1) “Fracking” should be opposed; it is analogous to mountaintop removal and tar sands, producing local pollution while making the global climate problem practically unsolvable, (2) existing nuclear power plants in the U.S., which are operating safely under supervision of the Nuclear Regulatory Commission and have saved an enormous number of lives and avoided large carbon emissions,[9] should continue to be used until one or both of the options discussed above (renewable energy + energy storage and improved nuclear power) are available.  The practical alternatives today to maintaining existing nuclear power are gas alone or gas supplementing subsidized intermittent renewable energies, in either case locking in gas and probably “fracking” for at least half a century, thus assuring that the climate problem is practically unsolvable.  If the U.S. keeps fracking, so will the world.

I have not checked statements of the political candidates, but it will be interesting and important to see their responses to questions on these topics. In the primaries there is a tendency in both parties to push candidates to the extremes.  On the liberal side that means oppose fracking and nuclear power; it will be interesting to see if any candidate is responsibly “Presidential”.  On the conservative side, it seems that nobody has the courage to oppose climate change denial; thus it seems that any of these candidates will go whole hog in burning more fossil fuels.

So I am not recommending any candidate after all.  The only thing I would say is that we had better make maximum effort to help the winner understand the climate/energy story this time.

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