A new study has revealed that melting Greenland’s ice sheets “increases the risk of floods worldwide”, with more than 3.5 trillion tons disappearing in the past decade.
A team of scientists, led by a research group at the University of Leeds, determined that the melt increased sea levels worldwide by one centimeter, using satellite data of the massive ice sheets.
A third of the rise occurred in just two seasons – 2012 and 2019 – when extreme weather led to record levels of snowmelt not observed in the past 40 years.
During these summers, warm air moved over much of the ice cap margin, the space between the ice and the glacier, increasing surface melt.
Recent satellite images showed that snowmelt varies greatly depending on the season and has been a major cause of heat waves flowing around Greenland.
Scientists have estimated that melting Greenland’s ice sheet has caused about 25% of the global sea level rise seen over the past few decades.
And if all of Greenland’s ice melted, global sea level would rise by another 20 feet – but that’s not expected any time soon.
“As we have seen in other parts of the world, Greenland is also prone to increased extreme weather events,” Thomas Slater, from the University of Leeds’ Center for Polar Monitoring and Modeling, told AFP. Greenland often.
Slater and colleagues used the CryoSat-2 satellite to collect ice-melt measurements from January 2011 through October 2020, in order to calculate surface-elevation changes across the Greenland ice sheet, the team wrote in the study published in Nature .
That data was then compared to 15,380 contemporary, independent estimates made from airborne laser altimetry, an instrument on Earth-orbiting satellites to map Earth’s topography — all of which showed how much Greenland’s ice sheets were melting.
“The heights of surface features can be calculated by comparing how long it takes a laser pulse to resonate at different locations,” NASA explained.
The team provided an example of data collected in 2012, which revealed changes in atmospheric patterns that caused unusually warm air to move over the ice sheet for weeks, losing more than 527 billion tons of ice.
A separate observation of Greenland found that its ice sheets lost 8.5 billion tons of surface mass on July 27, enough ice to cover Florida in two inches of water.
This extreme melt was the result of heat waves in northern Greenland that raised temperatures to more than 68 degrees Fahrenheit – twice the average summer temperature, according to the Danish Meteorological Institute.
While this volume was below the record for a single-day melt in 2019, which was 12.5 billion tons, the June event covered a larger area.
Melting events could create feedback loops that lead to further warming and melting in Greenland, according to Marco Tedesco, a climate scientist at Columbia University.
And when the snow melts, it exposes dark ice or the ground beneath it, which absorbs more sunlight rather than reflecting it back out of the atmosphere.
The Greenland Ice Sheet is the second largest mass of freshwater ice on the planet, with an area of about 695,000 square miles, second only to Antarctica.
The melting of the ice sheets began in 1990 and has accelerated since 2000.
Researchers at Polar Portal say mass loss in recent years is four times greater than it was before 2000.
Greenland’s thaw usually begins in June and lasts through August, but data shows the island has lost more than 100 billion tons of ice since June.
Source: Daily Mail