Greenland Ice Sheet Holds Summer Meltwater: Surprising New Discovery Challenges Sea-Level Rise Predictions

Greenland ice sheet (east coast) [credit: Hannes Grobe @ Wikipedia]

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Scientists call it the water buffering effect. ‘Challenges’ climate models is putting it politely. Adjustments of up to 20% for the warmest years may be needed. We’re told ‘The Greenland Ice Sheet is currently the largest single contributor to global sea-level rise’ – but not as large as currently believed, it seems..
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A recent study published in Nature reveals an unexpected discovery: a significant volume of meltwater is temporarily stored within the Greenland Ice Sheet during the summer, says SciTechDaily.

For the first time, an international team of researchers has measured this meltwater using precise positioning data. This breakthrough challenges existing models of ice sheet contributions to global sea level rise.

The Greenland Ice Sheet is currently the largest single contributor to global sea-level rise, with the potential to raise the mean sea level by up to seven meters if it fully melts.

While scientists have long studied the melt processes of the ice sheet, one crucial question has remained unanswered: how does meltwater storage evolve within the ice sheet throughout the summer melt season? A new approach provides an unprecedented view into the movement and storage of meltwater.

“During the melt season, we found that a significant fraction of meltwater mass is stored temporarily within the ice sheet,” says Jiangjun Ran, associate professor at Southern University of Science and Technology. “This water buffering effect peaks in July and slowly recedes in the following weeks.”

Novel approach to water monitoring
“Understanding how water is stored and released within the ice sheet has always been a challenge,” says Pavel Ditmar, associate professor at Delft University of Technology. The team has utilized data from the Greenland GPS Network (GNET).
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Implications for climate models
This discovery will help improve climate models, which often underestimate the complexity of water storage within ice sheets. Especially during warmer years, models that predict water runoff toward the ocean may easily underestimate that process. The study finds that these models could require scaling adjustments of up to 20% for the warmest years.

“These findings are crucial for improving forecasts of the Greenland Ice Sheet’s contribution to future sea-level rise,” says Michiel van den Broeke, professor at Utrecht University. “With climate change making the Arctic warmer than ever, accurate predictions are essential for preparing coastal regions for potential sea-level rise.”

Full article here.
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Image: Greenland ice sheet (east coast) [credit: Hannes Grobe @ Wikipedia]