The first episode of the Netflix documentary sequence Our Planet includes a violin-filled requiem for an iceberg the dimensions of a skyscraper. Because it breaks from the Greenland Ice Sheet and drives a huge tidal wave, narrator David Attenborough explains that glaciers have at all times launched ice into the ocean. What’s completely different now could be that it’s taking place extra typically — and following a study launched Monday in PNAS, it’s occurring at a more and more speedy price.
Watching a glacier crack with a rumble into the ocean is a formidable sight, however, to perceive what’s occurring with the Greenland Ice Sheet — a mass of glacial land ice three times the dimensions of Texas — it’s essential to take a look at its evolution by way of a historical lens. It’s vital, co-creator Eric Rignot, Ph.D., a professor on the College of California, Irvine, tells Inverse, to put the latest mass loss into an extended-time period context.
Earlier research demonstrated that, in 2012, the annual ice loss was already almost four instances the speed it was in 2003. What Rignot and his staff discovered within the new examine was alarming: The Greenland Ice Sheet has undergone fast and irreversible change, they usually can pinpoint precisely when the local weather of the planet took a horrible flip.
To return to this conclusion, they evaluated 46 years price of knowledge documenting the ice velocity, thickness, and floor elevation of 260 glacial drainage basins. They plugged this knowledge into superior atmospheric climate models that allowed them to estimate charges of ice accumulation, sublimation, melting on the glacier surface, and the rate and thickness of ice discharge into the ocean.
The information present that within the ‘70s, the Greenland Ice Sheet gained a mean of 47 gigatonnes of ice per year. However, by the 1980s, it was losing a way of 50 gigatonnes of ice yearly. Rignot explains that is the time when “the climate of the planet drifted off its pure variability to turn into dominated by warming from human exercise.”
Shedding ice is now the brand new regular. Because of the ‘80s, the rate of ice loss has elevated sixfold. From 2010 to 2018, the average loss was 290 gigatonnes of ice per year.