Published on June 30th, 2017 | by James Ayre0
Study: Sunnier Skies, Not Just Temperature Rise, Driving Greenland Ice Sheet Melting
June 30th, 2017 by James Ayre
The skies over Greenland have become sunnier in recent years, and this has been driving the melting of the ice sheet there to a notable degree — in other words, it’s not just rising temperatures that are causing the ice sheet there to melt. This is according to a new study from the University of Bristol.
Image by Black and Boom
Going by the findings, which rely on climate models rather than direct evidence, around two-thirds of Greenland’s surface ice sheet melting during the past two decades has been driven by decreasing cloud cover, and one-third by rising air temperatures there.
The researchers argue that if global climate models are to more accurately predict the rate and timing of the melting of the Greenland ice sheet, they will need to better represent the relationship with cloud cover.
As a reminder here, if all of the Greenland ice sheet was to melt, then average global sea levels would rise by around 23 feet.
Climate Central provides more: “Global sea level has already risen by about a foot since 1900. Greenland’s contribution to that rise has jumped since the 1990s, accounting for about 30% of sea level rise since then.”
“… Stefan Hofer, a PhD candidate at the University of Bristol in England, and his colleagues looked into what the main drivers of that surface melt were, in particular the effect of cloud cover on melt. In satellite data spanning the past two decades, they saw a significant decrease in cloud cover over Greenland starting in the mid-90s, which would mean more sunlight was falling on the ice and driving melt.
“Climate models the team used suggest that every 1% reduction in cloud cover leads to another 27 gigatons of melt (the US uses about 1.3 gigatons of water per day, according to data from NASA and the US Geological Survey).”
In an email to Climate Central, Hofer noted that: “Our results clearly show that the reduction in summer cloud cover is an important driver in the recent melt increase on the Greenland ice sheet.”
While the presence or lack of cloud cover is as noted above an important factor in the degree of ice sheet melting in Greenland, rising temperatures there are on their own driving significant melting as well. Regardless of the presence of cloud cover or not, there are big changes coming to Greenland, and the world’s coastlines, over the coming decades.
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