Climate Letter #1141

From Antarctica, fears of a worst-case sea level rise have been bolstered.  From 2010 to 2016, eight of the continent’s 65 major ice streams retreated at more than five times their historical average.  Most of the effect is due to melting from the underside, causing their grounding lines where they meet the ocean to move inward.  The worst-case Antarctic meltdown is now thought to imply the possibility of a 10-foot rise in sea level by 2100, far more than anyone is ready for.
https://insideclimatenews.org/news/02042018/antarctica-ice-sheet-shelf-glaciers-grounding-line-receding-worst-case-sea-level-rise-risk
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How effective is 2C as a target for limiting global warming?  The upper of two numbers set by the Paris Agreement was never selected on the basis of rigid scientific studies, and has always been subject to review.  Now a large set of varied and coordinated studies have been issued all at one time, just today, through a project aiming at testing the merits of that 2C number.  This report from France is the first I have seen that takes a look at the results, leaving an impression that the predicted outcome would indeed be more than highly destructive.  With a 1.5C limit all but ruled out as impossible, there can still be hope for achieving a 1.7-1.8C target if people get serious and are willing to make the required effort.  (Getting this kind of information out and having it widely accepted must somehow be accomplished before that is likely to happen.) https://www.afp.com/en/news/205/two-degrees-no-longer-seen-global-warming-guardrail-doc-13k38n1

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Here is an example of what is happening today in regions where drought is a cause for migration.  In this story from India the focus is on those who are left behind.  “Odisha is among the poorest states in India with one of the highest migration rates, often fuelled by drought and an overall lack of jobs. An estimated 500,000 people migrate from this part of the state every year, more than half to work in brick kilns.”
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Deforestation in Argentina, for the sake of soya bean farming, is having a really weird effect on the landscape.  Nature, when disturbed, is full of surprises.  “Argentina’s transformation into a soya bean powerhouse has resulted in widespread deforestation to make way for the crop, which now covers of 60% of the country’s arable land. Some 2.4m hectares of native forest have been lost in the last 10 years, according to Greenpeace.”
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Researchers have made a fundamental discovery that adds to the reasons why forests are shrinking.  What they learned in Brazil could also be true in other places.  “Their study implies that when patches of tropical forest lose their natural shape it could contribute to the sudden, even catastrophic, transformation of that land from trees to grass.”  The natural shape of a forest is the result of evolutionary processes that favor lasting stability if left alone.
https://phys.org/news/2018-03-collapse-tropical-forests.html
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A South Dakota farmer is showing that using proper practices to grow corn results in better yields, healthier soil and a large amount of carbon being permanently sequestered in the ground, net of operating emissions.
Carl
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