[GWSG] Nanjing U on CH4; Science Daily's take; 100 yrs or 20?; runaway feedback?; US lacks policy; or maybe not

[Tilley, Al]

1. Nature Communications has made the Nanjing U methane article openly available. It calculates that we have been underestimating the positive feedback effects of global heating on methane buildup in the atmosphere by a factor of four. The article is opaque to me, although I can get through the one paragraph summary at the beginning. https://www.nature.com/articles/s41467-022-31345-w.pdf

2. The Science Daily summary of the Nanjing U methane article repeats the misleading info that CH4 is 25 times more damaging than CO2 but attempts to make the article more available to non-specialists. https://www.sciencedaily.com/releases/2022/06/220630083306.htm

3. CH4 breaks down in the atmosphere until, about 100 years from release, it traps about 25 as much heat as does CO2. Within about 20 years from its release, though, it does 80-100 times the damage. It is on that time scale that accumulating methane threatens to set off a self-sustaining positive feedback. A short piece describes the CO2-CH4 equivalence problem: https://climate.mit.edu/ask-mit/why-do-we-compare-methane-carbon-dioxide-over-100-year-timeframe-are-we-underrating

4. The possibility of a runaway feedback, beyond our ability to control it, is a major implication of the Nanjing U article, in my imagination of the situation. A few years ago, calculations of the methane release from melting permafrost and clathrates, and of the rate of heat buildup in the Arctic, indicated that runaway heating was not likely. Articles in Nature and Science in 2020 concluded that ancient methane from clathrates and permafrost were unlikely to initiate runaway warming. (We may thank the bacteria which eat much of the released methane.) https://cosmosmagazine.com/earth/climate/ancient-stores-of-methane-may-not-be-a-threat-study-suggests/
I fear that the Nanjing U article indicates that a new estimate of the heating effects of atmospheric methane may reverse that projection. I very much hope that a better-informed list member will disabuse me of the concern. I will pass on what I learn.

5. “The US, almost uniquely among major democracies, still has no national climate or energy policy in place.” The Supreme Court ruling against EPA regulation of emissions, and the opposition of coal baron Sen. Joe Manchin (along with every Republican in the senate) to any climate action, has wakened fears around the world that no coherent action plan is on the horizon for the US.  https://www.theguardian.com/environment/2022/jul/06/supreme-court-epa-ruling-biden-climate-policy-global-reaction

6. George Monbiot sees the Supreme Court’s EPA decision as part of “what appears to be an ideological commitment to destroying life on Earth. The UK government and the US supreme court look as if they are willing the destruction of our life support systems.” Sen. Sheldon Whitehouse observes that in the US, the movement has been well funded over a period of many years.  https://www.theguardian.com/commentisfree/2022/jul/06/power-wealthy-earth-politics-democracy-plutocracy

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.unf.edu/pipermail/gwsg/attachments/20220706/4ceff198/attachment.htm>