Researchers at the University of California, Irvine and Utrecht University in the Netherlands have found that surface ice in Greenland is melting at an increasing rate, while the trend in Antarctica is moving in the opposite direction.
The study, published in the American Geophysical Union journal Geophysical Research Letters, studied the role of Foehn and katabatic winds, which bring warm, dry air into contact with glacier tops. The researchers found that the melting of the Greenland ice sheet due to these winds has increased by over 10% in the past 20 years, while the impact on the Antarctic ice sheet has decreased by 32%. The researchers also found that surface melt leads to runoff and ice shelf hydrofracture, increasing freshwater flow to oceans and causing sea level rise.
Greenland’s surface ice melt is attributed to a 10% increase in wind-driven melt and warmer surface air temperatures, resulting in a 34% increase in total surface ice melt. This is partly due to global warming’s influence on the North Atlantic Oscillation, which shifts to a positive phase, causing below-normal pressure across high latitudes. In contrast, Antarctic surface melt has decreased by 15% since 2000, largely due to 32% less downslope wind-generated melt on the Antarctic Peninsula. The Antarctic stratospheric ozone hole is recovering, temporarily insulates the surface from further melt.
Greenland and Antarctica’s ice sheets, which keep over 200 feet of water out of the ocean, have caused a three-quarters of an inch rise in global sea levels since 1992. Greenland is the leading cause of sea level rise, while Antarctica is catching up. Monitoring and modeling melt as both ice sheets deteriorate is crucial, including understanding how climate change affects the relationship between wind and ice. Research on Foehn and katabatic winds in polar regions can help strengthen Earth system models in the climate science community.