Greenland's ice is melting so quickly that the giant island is rising by nearly an inch per year in some coastal areas, according to US researchers. The rise seems to be increasing as the huge ice cap pushing down much of Greenland disintegrates.
The scientists from the University of Miami used specialised GPS receivers stationed on Greenland’s rocky shores to collect and study data dating back to 1995. The raw GPS data at each site was analysed for position, vertical velocity and acceleration.
The measurements are restricted to places where rock is exposed, limiting the study to coastal areas. However, previous data indicates that ice in Greenland's interior is in approximate balance as yearly losses from ice melting and flowing toward the coast are balanced by new snow accumulation, which gradually turns to ice.
Most ice loss occurs at the warmer coast, through melting and iceberg calving, and where the GPS data is most sensitive to changes. In western Greenland, the uplift seems to have started in the late 1990s.
"During ice ages and in times of ice accumulation, the ice suppresses the land," explained Shimon Wdowinski, research associate professor at the Rosenstiel School of Marine and Atmospheric Science at the University of Miami. Wdowinski co-authored the study.
"When the ice melts, the land rebounds upwards," he said. "Our study is consistent with a number of global warming indicators, confirming that ice melt and sea level rise are real and becoming significant."
If current trends continue, land rise could accelerate to as much as two inches per year by 2025, said Tim Dixon, professor of geophysics and principal investigator of the study.
"It's been known for several years that climate change is contributing to the melting of Greenland's ice sheet," Dixon said in a statement. "What's surprising, and a bit worrisome, is that the ice is melting so fast that we can actually see the land uplift in response."
Dixon added: "Even more surprising, the rise seems to be accelerating, implying that melting is accelerating."
