The East Antarctic Ice Sheet (EAIS), so-called “sleeping giant”, which holds the majority of glacier ice on Earth, is closer to being “awakened” than scientists have previously believed. In research published this week, a team of scientists analyzed how EAIS behaved during warm periods in Earth’s past to predict how it will fare as the world continues heating. Recent satellite images already show signs of thinning ice and melting.
“A key lesson from the past is that the EAIS is highly sensitive to even relatively modest warming scenarios. It isn’t as stable and protected as we once thought,” said co-author Professor Nerilie Abram, from Australian National University’s Research School of Earth Sciences.
If the global average temperature remains well below 2C, then EAIS is projected to add less than half a metre (1.6ft) to sea levels over the coming centuries, the researchers discovered. (Earth has warmed 1.1C in the past 150 years, and is on a pathway to 2.7C by 2100.)
Without curbing temperature rise, which is largely caused by emissions from burning fossil fuels, the projections are much more extreme, scientists found. EAIS melting alone – not accounting for West Antarctica or the Arctic – could contribute three to 10 feet (1-3m) of sea-level rise by 2300, and seven to 16.4ft (2-5m) by 2500. Centuries away, sure, but the “awakening” will likely be seen in the coming decades.
Scientists are working to better comprehend the severity of the situation. “We understand the Moon better than East Antarctic,” said Professor Matt King, from University of Tasmania. “So, we don’t yet fully understand the climate risks that will emerge from this area.”
Nasa’s Jet Propulsion Laboratory in California also released a first-of-its-kind study this week on Antarctica. It found that coastal glaciers are shedding icebergs faster than the ice can be replaced, doubling previous estimates of losses over the past 25 years.
“Antarctica is crumbling at its edges,” said Nasa scientist Chad Greene, lead author of the study. “And when ice shelves dwindle and weaken, the continent’s massive glaciers tend to speed up and increase the rate of global sea level rise.”
At the other pole, another group of scientists announced on Thursday that the Arctic is now warming four times faster than the rest of the world. The polar region was previously thought to be warming at 2-3 times faster than other parts of the planet. These new findings outpace current climate models – which are used to make future predictions – and so call into question how the Arctic will behave going forward.
Why’s all this important? Sea level rise leads to flooding, eats into shorelines and makes storms more dangerous. Some of the world’s largest cities – home to tens of millions of people – are located near coastlines including including New York, Tokyo, Los Angeles, Mumbai, Shanghai and Lagos.