Extreme ice melting in Greenland caused by global warming raises worldwide flood risk

Global warming has made extreme ice melting events in Greenland more frequent and more intense, raising the risk of sea level rises and floods around the world, according to a study.

In the past decade, 3.5 trillion tonnes of ice has melted from the surface of the island and flowed into the ocean – enough to cover the entire UK with meltwater around 45 feet deep.

A study led by researchers at the University of Leeds is the first to use satellite data to detect this phenomenon (known as ice sheet runoff) from space.

The findings, published in Nature Communications, reveal that Greenland's meltwater runoff has risen by 21% over the past four decades and has become 60% more erratic from one summer to the next.

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Lead author Dr Thomas Slater, a research fellow at Leeds' Centre for Polar Observation and Modelling, said: “As we’ve seen with other parts of the world, Greenland is also vulnerable to an increase in extreme weather events.

“As our climate warms, it’s reasonable to expect that the instances of extreme melting in Greenland will happen more often – observations such as these are an important step in helping us to improve climate models and better predict what will happen this century.”

The research shows that over the decade from 2011 to 2020 increased meltwater runoff from Greenland raised the global sea level by one centimetre.

One-third of this total was produced in just two hot summers, 2012 and 2019, when extreme weather led to record-breaking levels of ice melting not seen in the past 40 years.

Raised sea levels caused by ice melt heightens the risk of flooding for coastal communities worldwide and disrupts marine ecosystems in the Arctic Ocean that indigenous communities rely on for food.

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The changes are related to extreme weather events, such as heatwaves, which have become more frequent and are now a major cause of ice loss from Greenland because of the runoff they produce.

Dr Slater said: “There are, however, reasons to be optimistic. We know that setting and meeting meaningful targets to cut emissions could reduce ice losses from Greenland by a factor of three, and there is still time to achieve this.”

Dr Amber Leeson, senior lecturer in environmental data science at Lancaster University, said: “Model estimates suggest that the Greenland ice sheet will contribute between about 3cm and 23cm to global sea level rise by 2100.

“This prediction has a wide range, in part because of uncertainties associated with simulating complex ice melt processes, including those associated with extreme weather.”

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