[GWSG] East Antarctic diatoms & sea level rise; McKibben updates his math

[Tilley, Al]

1.  A significant deposition of marine diatoms on glacial sedimentary rocks in the East Antarctic has puzzled students of the region.  Were they carried up there by glaciers or did they settle when they were blown there by the wind?  A new study indicates that both answers deserve prizes, with an implication that the East Antarctic Ice Sheet is less stable than we had supposed, and that significant sea level rise is possible within a few decades.  The first, two-minute, video in the linked Climate Crocks account discusses the diatom study, and the second, six-minute, video puts the news in the context of global sea level rise as we understand it now.  The last time the earth saw current levels of warming the oceans rose at an average rate of a meter every two decades.  We are ripe for new estimates of the rate of sea level rise to expect in the near future, and, at the high end, they are more likely to resemble Jim Hansen's estimate of five meters by 2100 than the current NOAA estimate of two meters (or the IPCC figures, around a meter).  The diatom study may have been among the new research Margaret Davidson, NOAA's Senior Leader for Coastal Inundation and Resilience, had in mind last April when she announced to the risk managers of the insurance industry her estimate of as much as 3 meters of sea level rise by 2050-60.  https://climatecrocks.com/2016/09/24/antarctic-sediments-add-pieces-to-sea-level-puzzle/  Northern Illinois U supplies a fuller account of the East Antarctic diatom study:  https://www.sciencedaily.com/releases/2016/09/160921103712.htm  Chris Mooney of the Washington Post provides another informed discussion of the diatom study.  The study is surely one of the most significant for our planning because it points to the potential contribution of major sea level rise from the East Antarctic, where we had thought we were secure from threat for centuries yet.  https://www.washingtonpost.com/news/energy-environment/wp/2016/09/20/scientists-may-have-just-solved-a-riddle-about-antarctica-and-youre-not-going-to-like-the-answer/?utm_term=.896465ec9eef



2.  If we would like to keep warming below 2C, how much more development of fossil fuels can we undertake?  None.  In fact, the currently operating fields and mines will produce enough to take us over the edge if we continue to use them.  To have an even chance of keeping below 1.5C of warming we would need to leave about 2/3 of the currently exploited resources unused.  Recalculating the Climate Math updates Bill McKibben's article from four years ago, Global Warming's Terrifying New Math.  McKibben suggests a course toward climate stability which does not require simply shutting down the energy supply immediately.  https://newrepublic.com/article/136987/recalculating-climate-math  ?

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