The melting of Greenland’s ice sheets is ‘heightening worldwide flood risks,’ according to a new study that found more than 3.5 trillion tons have disappeared in the past decade.
A team of scientists led at the University of Leeds discovered that melting has caused an increase of one centimeter in global sea level. They used satellite data of the huge ice sheets to make this determination.
One third of the rise occurred in just two summers — 2012 and 2019 — when extreme weather led to record-breaking levels of ice melting that has not been observed in the past 40 years.
These summers saw increased surface melting due to warm air moving over large portions of the ice sheet margin.
Satellite images captured recently showed that ice melt varied greatly depending on the season. This was largely due to heatwaves around Greenland.
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The melting of Greenland’s ice sheets is ‘heightening worldwide flood risks,’ according to a new study that found more than 3.5 trillion tons have disappeared in the past decade
Scientists estimate that the melting of Greenland’s Ice Sheet has contributed approximately 25% to the global sea level rise over the past few decades.
The global sea level would rise by 20 feet more if all of Greenland’s glaciers were to melt. However, this is unlikely to happen anytime soon.
Thomas Slater, from the University of Leeds Centre for Polar Observation and Modelling and lead author, told AFP: ‘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.’
Scientists determined the melting has increased global sea levels worldwide by one centimeter using satellite data of the massive ice sheets
The team published their study in Nature. It was written by Slater and his collaborators. They used a CryoSat-2 satellite for ice melt measurements between January 2011 and October 2020 to calculate surface elevation changes across Greenland Ice Sheet.
This data was then compared to 15,380 contemporaneous and independent estimates determined from airborne laser altimetry, a device on planet-orbiting satellites to map Earth’s terrain – all of which showed how much of Greenland’s ice sheets have melted.
According to NASA: ‘The elevations of surface features can be calculated by comparing how long it takes a laser pulse to echo back at different locations.’
The team gave an example of data they had collected in 2012. It showed that unusually warm air hovered over the ice sheets for weeks due to changes in atmospheric patterns. In total, 527 billion tons of glacier was lost.
Study co-author Amber Leeson, senior lecturer in Environmental Data Science at Britain’s Lancaster University, said in a statement: ‘Model estimates suggest that the Greenland ice sheet will contribute between 3-23 [centimeters]To global sea-level increase by 2100
Scientists used a 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
‘These new spaceborne estimates of runoff will help us to understand complex ice melt processes better… and just enable us to refine our estimates of future sea-level rise.’
A separate observation of Greenland found its ice sheets lost 8.5 billion tons of surface mass on July 27, enough ice to cover Florida in two inches of water.
According to the Danish Meteorological Institute, this extreme melting was caused by heatwaves in northern Greenland which raised temperatures to more that 68 degrees Fahrenheit – twice the average summer temperature.
While that volume was less than the record single-day ice melt in 2019, which was 12.5 billion tons, June’s event covered a larger area.
Greenland’s ice sheet lost 8.5 billion tonnes of surface mass in a separate observation on July 27, which is enough to cover Florida by two inches of water.
According to Marco Tedesco (climate scientist at Columbia University), melting events can create feedback loops which drive further warming and melting of Greenland.
When snow melts, it exposes darkened ice and ground beneath. These absorb more sunlight than reflect it back out into the atmosphere.
‘It really positions Greenland to be more vulnerable to the rest of the melting season,’ Tedesco, research professor at Columbia University´s Lamont-Doherty Earth Observatory, told Reuters.
With nearly 695,000 sq miles, the Greenland Ice Sheet is second in freshwater ice mass on the planet.
The melting of ice sheets began in 1990, and has been increasing rapidly since 2000.
According to Polar Portal researchers, the mass loss in recent years has been approximately four times greater that it was before 2000.
Greenland’s melting is usually seen in June and continues until August. But, data shows that the island lost more than 100 million tons of ice between June and June.