Satellite Monitoring of Greenland Ice Melting Highlights Increasing Global Flood Risk

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Surface Meltwater Flowing in Greenland

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Surface meltwater streaming towards the ocean through a channel inGreenland Credit: Ian Joughin

Global warming has actually triggered severe ice melting occasions in Greenland to end up being more regular and extreme over the past 40 years, raising water level and flood threat worldwide, discovers brand-new research study including University College London (UCL) academics.

Over the previous years alone, 3.5 trillion tonnes of ice has actually melted from Greenland’s surface area and streamed into the ocean– adequate to cover the UK with around 15 m of meltwater, or all of New York City with around 4500 m.

Published previously this month in Nature Communications, the brand-new research study is the very first to utilize satellite information to find this phenomenon– referred to as ice sheet overflow– from area.

Funded by the European Space Agency (ESA) as part of its job ‘Polar+ Surface Mass Balance Feasibility’, the research study utilized measurements from the ESA’s CryoSat-2 satellite objective, utilizing quotes of surface area elevation modification with time.

One of the extremely couple of satellites orbiting with 2 degrees of the world’s poles, CryoSat-2 has actually supplied researchers with a long history of information no other spacecraft might reach because its launch over 11 years back, changing researcher’s capability to study the polar areas. It stays essential to research study and understanding important to decision-making on earth’s health.

Study co-author Lin Gilbert (UCL Mullard Space Science Laboratory) stated: “Observations show that extreme melt events in Greenland have become more frequent and more intense — as well as more erratic — which is a global problem. Monitoring from space enables us to cover the whole of Greenland (and nearly all Antarctica) repeatedly, which can’t be done by teams on the ground. This is the first-time run-off has ever been measured directly from space — allowing us to remotely observe hard-to-explore regions of the ice sheets and use these observations to form an enhanced understanding of why this is happening and what we can do about it in future.”

The worldwide group of scientists discovered that over the previous 4 years Greenland’s meltwater overflow has actually increased by 21%– and has actually ended up being 60% more irregular from one summertime to the next.

The findings revel that in between 2011 and 2020 increased meltwater overflow from Greenland raised the international water level by one centimeter– increasing the threat of flooding around the world and interrupting marine communities in the ArcticOcean Rising water level can likewise modify patterns of ocean and climatic flow that impact weather around the world.

One 3rd of this increase was produced in simply 2 summer seasons– 2012 and 2019– when severe weather condition resulted in record-breaking levels of ice melting not seen in the past 40 years.

The research study reveals that throughout the previous years, overflow from Greenland has actually balanced 357 billion tonnes of ice melt each year– corresponding to practically 1 millimeter of international water level increase– reaching an optimum of 527 billion tonnes in 2012, when modifications in climatic patterns triggered abnormally warm air to sit over much the ice sheet.

These modifications relate to severe weather condition occasions such as heatwaves, which have actually ended up being more regular and are now a significant reason for ice loss from Greenland.

Lead author Dr Thomas Slater (University of Leeds) stated: “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.”

“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.”

The research study observations can likewise be utilized to validate how environment designs mimic ice sheet melting, enabling enhanced forecasts of just how much Greenland will raise the international water level in future as severe weather condition occasions end up being more typical.

Study co-authorDr Amber Leeson (Lancaster University) stated: “Model quotes recommend that the Greenland ice sheet will contribute in between about 3– 23 cm to international water level increase by2100 This forecast has a wide variety, in part since of unpredictabilities related to mimicing intricate ice melt procedures, consisting of those related to severe weather condition.

“These new spaceborne estimates of runoff will help us to understand these complex ice melt processes better, improve our ability to model them, and thus enable us to refine our estimates of future sea level rise.”

For more on this research study, see Increased Global Flood Risk Due to Intense Frequency of Extreme Ice Melting in Greenland.

Reference: “Increased variability in Greenland Ice Sheet runoff from satellite observations” by Thomas Slater, Andrew Shepherd, Malcolm McMillan, Amber Leeson, Lin Gilbert, Alan Muir, Peter Kuipers Munneke, Brice No ël, Xavier Fettweis, Michiel van den Broeke and Kate Briggs, 1 November 2021, Nature Communications
DOI: 10.1038/ s41467 -021-26229 -4