[GWSG] Relocation; urgency at COP 25; CH4 leads; Greenland melt; permafrost melt; positive feedback prospects; NYT on feedback loop

Tilley, Al atilley at unf.edu
Wed Dec 11 07:23:45 EST 2019

1. A Nature article on sea level rise and human migration takes a broad view of relocation to avoid rising waters. People will not move if they can help it, though policies which assist and promote relocation can help. Hurricanes and other cyclones have yet to produce large population shifts—people tend to move back to the destroyed areas when they can. Governments generally are poorly prepared for managed retreat. Areas with large tracts of communally owned lands can relocate more easily, as in Fiji. Following principles of equitable adaptation makes relocation easier. In the US, “Half of those exposed to SLR reside in Florida and nearly a quarter in Miami, Florida alone.”   https://www.nature.com/articles/s43017-019-0002-9

2. So far the COP 25 climate meeting in Madrid has lacked appropriate urgency. Things may improve this week. https://www.theguardian.com/environment/2019/dec/09/cop25-climate-summit-what-happened-during-first-week

3. Natural gas (commercial methane) now emits more carbon in the US than coal. Globally, gas is now the primary driver of growth in greenhouse gas emissions. It is a bridge that leads nowhere we would want to go.   https://www.eenews.net/stories/1061760587

4. Greenland is losing ice seven times faster than it was in 1990. That pushes sea level rise to the high end of IPCC expectations, requiring that a new high end be defined to allow for more acceleration of the melt. https://www.washingtonpost.com/climate-environment/2019/12/10/greenland-ice-losses-have-septupled-are-pace-sea-level-worst-case-scenario-scientists-say/

5. Permafrost is melting in the Arctic much faster than anticipated, releasing methane and CO2 which will drive further heating, and thus to further melting of the permafrost, a positive feedback we had hoped would come much later. https://www.washingtonpost.com/weather/2019/12/10/arctic-may-have-crossed-key-threshold-emitting-billions-tons-carbon-into-air-long-dreaded-climate-feedback/

6. The general expectation is that a permafrost-methane feedback would add about a half degree C this century, as reported from Woods Hole in this 2015 Guardian article. https://www.theguardian.com/environment/climate-consensus-97-per-cent/2015/oct/13/methane-release-from-melting-permafrost-could-trigger-dangerous-global-warming We should keep an eye out for recalculations. Abrupt thawing appears to be the greatest threat. https://climate.nasa.gov/news/2785/unexpected-future-boost-of-methane-possible-from-arctic-permafrost/

7. The New York Times surveys the NOAA report which is the basis for the preceding story. They report that the permafrost-methane feedback is not yet established, though it may be starting. Once the feedback loop is established we do not yet see a way to interrupt it. https://www.msn.com/en-us/weather/topstories/climate-change-is-ravaging-the-arctic-report-finds/ar-BBY2nzW?ocid=spartandhp

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