Wind is thawing Greenland, but also helping Antarctica retain its ice sheets somehow

When we let loose our end of the tug o' war rope against climate change, there will be little we'll be able to do to protect our coastal cities from its watery rampage. And as the oceans claim the likes of Mumbai and New York, at least we'll know where all the water is coming from.

Even if you leave the various glacier-laced mountains out of the equation, the ice sheets in Greenland and Antarctica hold enough frozen water to raise sea levels by 210 feet. And sadly enough, these landmasses comprise the two regions most severely affected by global warming.

The world is getting hotter, there are no two ways about it. Greenland itself has faced a massive 3.8°C rise in temperature since the 1990s. But rising air temperatures aren't the only factors leading to the ice sheet's accelerated downfall, either. Wind also forms a major contributor.

However, a new study has found that the gusty phenomenon has clear favourites, even while attacking our two best ice reserves.

Foehn and Katabatic winds — downslope gusts that blow hot air on the tops of glaciers, akin to a hair-drier — contribute a major amount to the melting of Greenland and Antarctic ice sheets annually. The research team found that the impact of these winds on Greenland's ice sheets has spiked by as much as 10% in the past two decades. On the contrary, its effect on the Antarctic ice sheet has reduced by 32%.

Most of this major distinction can be attributed to the way global warming is playing out differently in Earth's northern and southern hemispheres. Greenland has become so hot that it no longer needs wind, with the effect of sunlight substantial enough to drive melting in the region. The 10% extra wind-driven melt has just exacerbated total surface ice melt by 34% over the last 20 years.

Further, a shift of the North Atlantic Oscillation — an extremely important weather phenomenon controlling the strength and direction of western winds and storms in the region — to a positive phase is bringing in more warm air over Greenland and other Arctic areas. The hair drier has been left in an on-state, essentially.

Meanwhile, total Antarctic surface melt has slashed by around 15% since 2000, mostly due to 32% less downslope winds on the peninsula. Further, an improvement in the region's ozone layer, which absorbs a great deal of raw heat from the Sun, has insulated Antarctica's surface from further melting, the study suggests.

However, this doesn't mean that the southern ice sheet is free from trouble. Antarctica has faced the collapse of two vulnerable ice shelves already. Further, research has suggested that if this melting trend continues, it could slow down global ocean water circulation patterns, which could have devastating consequences on Earth's climate, including rainfall and warming.

"Although Greenland has been the number one driver of sea level rise in recent decades, Antarctica is close behind and catching up and will eventually dominate sea level rise," explains Charlie Zender, an author. "So it's important to monitor and model melt as both ice sheets deteriorate, including the ways climate change alters the relationship between wind and ice."

The findings of this research have been published in Geophysical Research Letters and can be accessed here.