When climate scientists look at Antarctica, they see a ticking time bomb. If the ice sheet melts, it will raise sea levels by tens of feet, flooding coastal cities around the globe. The southern continent is relatively stable, but rising temperatures are melting the island from the inside out. Two new studies published in the journal Nature catalogue the melting and explain what it could mean for sea-level rise.
Researchers examined decades of photos from satellites and military aircraft documenting hundreds of meltwater channels around the perimeter of the continent. They traced some streams deep into Antarctica’s frozen interior and discovered ponds of meltwater more than 4,000 feet above sea level, where no one expected to find liquid H2O.
In some places, the terrain had contributed to the melting. Blue ice and dark mountains absorb more sunlight than the white snow. These features gathered the extra heat needed to thaw Antarctic. Meltwater channels tend to grow in warmer months and refreeze in the winter. But scientists worry that rising temperatures spur continual melting, accelerating sea-level rise.
Ice shelves along the edge of the continent holding back massive, terrestrial glaciers ae breaking up, allowing glaciers to slip into the ocean. Meltwater may, in some instances, lubricate the underside of the glacier, hastening its passage. Meltwater can also burrow into the ice shelf, cleaving apart large chunks of ice, what's currently happening to the Larsen C Ice Shelf, which is expected to break off the continent soon.