Extreme ice melt observed at Greenland's summit
The Greenland Ice Sheet is melting at an unprecedented rate as temperatures at Greenland’s summit reach the highest ever observed.
This week, scientists recorded temperatures above 0°C at Greenland’s summit. This is only the third time temperatures have been recorded above freezing, but the second time this summer. These unusually high temperatures are accelerating ice loss from Greenland's Ice Sheet, which covers 80% of the island.
Changes to the Greenland Ice Sheet are important because the ice plays a significant role in modern-day sea level rise. As more ice melts, sea-levels will rise more quickly and higher.
Greenland’s summit sits 3,200m above sea level and rarely experiences temperatures anywhere close to thawing. Looking back in time, ice core records show that melting at the summit has typically occurred once every 150 years. Now, scientists have observed three melt-events within the last seven years.
The increased melting on Greenland's Ice Sheet is a symptom of global changes in climate, said Dr Ryan Neely, an Associate Professor within NCAS and the School of Earth and Environment at the University of Leeds, who has studied the atmosphere above Greenland since 2010. He points out:
“This is the most extreme melting we have ever observed at Greenland’s summit. We’ve never seen multiple days of melting in one week before.”
Measuring the melt
The Greenland Ice Sheet is the only permanent ice sheet outside Antarctica and its role in sea level rise has led an international team of researchers, including Dr Ryan Neely, to set up a programme of long term observations on the island.
The National Science Foundation fund a year‐round observing station at Greenland summit, which is used for a wide range of scientific investigations.
As part of the Integrated Characterization of Energy, Clouds, Atmospheric state, and Precipitation at Summit (ICECAPS) project, scientists are looking at how clouds form and dissipate above Greenland and how that affects the mass of the ice sheet below. Their observations are helping to answer important questions about how much melt water is being released by melting ice sheets, and how will it impact on sea level rise.
Greenland’s ice sheet routinely experiences melting on a seasonal basis, but increasingly severe melting events are causing the region to lose more ice each summer than is replenished in winter. Since 2010 the ice sheet has been losing around 300 billion tons of ice each year, equivalent to a sea level rise of around 0.8mm.
Future ice loss
The observed temperatures at Greenland’s summit are a strong indication that 2019 will continue the trend for increasing ice loss. Researchers hope that better understanding the atmospheric processes above Greenland will help improve predictions of future ice-melting, and understand the implications for the global climate.
Weather data collected by NOAA/ESRL/GMD Baseline Observatories shows the two above-zero temperatures recorded so far this year.
This year, additional funding from the Natural Environment Research Council and the National Science Foundation has allowed researchers to expand their suite of instrumentation at Greenland’s summit. There is now scope for the ICECAPS project to collect a detailed set of observations that will explore the role of aerosol in the formation of clouds and precipitation. and contribute to the Year of Polar Predictions, an international activity looking to improve climate projections in polar regions.