Not from CO2 or global warming. From Anthony Watts:
Another alarmist pillar collapses – Greenland melting due to old soot feedback loops and albedo change – not AGW
From the EARTH INSTITUTE AT COLUMBIA UNIVERSITY and the “we told you so time and again at WUWT” department comes this study which not only explains the “insta-melt” in the Summer of 2012, but the ongoing melting that has been incorrectly blamed on CO2, when instead it’s all about older soot embedded in snow coming around again to enhance melting combined with weather pattern changes..
And what is happening:
The feedback loops work like this: During a warm summer with clear skies and lots of solar radiation pouring in, the surface starts to melt. As the top layers of fresh snow disappear, old impurities, like dust from erosion or soot that blew in years before, begin to appear, darkening the surface. A warm summer can remove enough snow to allow several years of impurities to concentrate at the surface as surrounding snow layers disappear. At the same time, as the snow melts and refreezes, the grains of snow get larger. This is because the meltwater acts like glue, sticking grains together when the surface refreezes. The larger grains create a less reflective surface that allows more solar radiation to be absorbed. The impact of grain size on albedo – the ratio between reflected and incoming solar radiation – is strong in the infrared range, where humans can’t see, but satellite instruments can detect the change.
Historical record:
The study used satellite data to compare summertime changes in Greenland’s albedo from 1981 to 2012. The first decade showed little change, but starting around 1996, the data show that due to darkening, the ice began absorbing about 2 percent more solar radiation per decade. At the same time, summer near-surface temperatures in Greenland increased at a rate of about 0.74?C per decade, allowing more snow to melt and fuel the feedback loops.
This is big - CO2 is the popular whipping boy for all changes in climate and weather. Not so. Carbon Dioxide is the gas of life and carbon is a friendly element in all forms.
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