The Kangerlussuaq Glacier, one of Greenland’s largest tidewater outlet glaciers, is pictured in this false-color image captured by the Copernicus Sentinel-1 mission. Meaning ‘large fjord’ in Greenlandic, the Kangerlussuaq Glacier flows into the head of the Kangerlussuaq Fjord, the second largest fjord in east Greenland.
Each Sentinel-1 satellite carries an advanced radar instrument giving us a day-and-night supply of images of Earth’s surface. Remote sensing allows us to monitor ice sheets across the globe and keep track of all calving stages – from rift detection to iceberg breakaway – as well as measure ice cover and drifting icebergs.
This Sentinel-1 radar image combines three separate acquisitions during the summer of 2021 and shows visible changes on the ground and sea surface between three acquisition dates: June 4, June 16, and June 28. The array of colors represents the seasonal retreat of ice during this time.
At the top of the image, stable ice can be seen in white and is present in all three radar acquisitions. Ice and snow visible only in the early-summer acquisitions can be seen in bright yellow and are not present in the last acquisition as they have melted by this time. The different shades of red highlights ice and snow detected only in the first acquisition captured on June 4. Colors on the sea surface vary owing to surface currents and sea ice dynamics.
Research using satellite imagery suggests that since 2017, Kangerlussuaq has entered a new phase of rapid retreat and acceleration, and its ice front is now at its most retreated position since the early 20th century.
As global temperatures increase, the melting of the massive ice sheets that blanket Greenland has significantly accelerated, contributing to sea-level rise. Over the past decade alone, findings have revealed that 3.5 trillion tonnes of ice have melted from the Greenland ice sheet and spilled into the ocean – enough to cover the UK with meltwater 15 m deep.
Using data from ESA’s CryoSat mission, the research shows that extreme ice melting events in Greenland have become more frequent and more intense over the past 40 years, raising sea levels and the risk of flooding worldwide.
Raised sea levels heighten the risk of flooding for coastal communities worldwide and disrupt Arctic Ocean marine ecosystems, as well as altering patterns of ocean and atmospheric circulation – which affect weather conditions around the planet.
Observations of Greenland runoff from space can be used to verify how climate models simulate ice sheet melting which will allow improved predictions of how much Greenland will raise the global sea level in the future.