An Ice Free Planet

After Munich Re, Jolting Joe Romm canvassed some other doom sayers. The lead paragraph nicely summarizes the latest NASA warning on expected sea level rise.

Right now, we’re headed towards an ice-free planet. That takes us through the Eemian interglacial period of about 130,000 years ago when sea levels were 15 to 20 feet higher, when temperatures had been thought to be about 1°C warmer than today. Then we go back to the “early Pliocene, when sea level was about 25 m [82 feet] higher than today,” as NASA’s James Hansen and Makiko Sato explain in a new draft paper, “Paleoclimate Implications for Human-Made Climate Change.”

Holocene
Hansen and Sato say we’re at or very near the highest temperatures of the current Holocene interglacial… With further global warming of the order of 3-6°C, they assert, “multi-meter sea level rise on the century time scale are not only possible, but almost dead certain

This blog has relayed such warning before. This most recent warning from Hansen & Sato re-emphasize the non-linearity of tipping points.

We suggest that a nonlinear process spurred by an increasing forcing and amplifying feedbacks is better characterized by the doubling time for the rate of mass disintegration, rather than a linear rate of mass change. If the doubling time is as short as a decade, multi-meter sea level rise could occur this century. Observations of mass loss from Greenland and Antarctica are too brief for significant conclusions, but they are not inconsistent with a doubling time of a decade or less.

Other Climate Progress posts on the topic of sea level rise

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