Humans ‘may have lost control’ of the West Antarctic ice sheet, a new study warns.
Scientists from the British Antarctic Survey say inevitable melting due to warming caused by greenhouse gas emissions will raise sea levels in the coming decades.
Even if emissions are controlled to achieve the best possible scenario, the melting of the ice sheet will continue to accelerate this century, at a rate three times that of the 20th century.
If the ice sheet melts completely, enough water will be released to raise global sea levels by 5.3 meters.
However, scientists say it is ‘only’ likely that they will rise by one meter by the end of the century.
Humans ‘may have lost control’ of the West Antarctic ice sheet, a new study warns
Scientists from the British Antarctic Survey say inevitable melting due to warming caused by greenhouse gas emissions will raise sea levels in the coming decades.
Warming oceans, which absorb excess heat from the atmosphere, are eroding the ice sheet from below and this effect is most pronounced on the western side of the continent.
Scientists are not sure how much this is likely to contribute to global sea level rise, but if the entire West Antarctic Ice Sheet were to melt it would contribute about five meters, although this scenario is not considered likely.
East Antarctica, which contains about 95 percent of the continent’s ice, remains stable as far as scientists can tell. A recent study found that the amount of ice there has increased over the past thirty years, although it is melting rapidly in the west. with a net loss of about 7.5 trillion tons of ice.
How much this melting will contribute to rising oceans is not as well known as other polar regions such as Greenland’s glaciers.
Dr. Kaitlin Naughten of the British Antarctic Survey (BAS) and lead author of the study said research other than her own findings will contribute to sea level rise by about one meter by 2100.
She described her findings as follows: ‘It appears that we have lost control of the melting of the West Antarctic Ice Shelf in the 21st century.
“Our actions today will likely make a difference in the 22nd century and beyond, but that’s a timescale that none of us here are likely to experience.”
The research, published in the journal Nature Climate Change, has been described by scientists as ‘sobering’ as it points to inevitable sea level rise that is likely to devastate many coastal communities if they do not adapt.
If the ice sheet melts completely, enough water will be released to raise global sea levels by 5.3 meters.
In Britain, the Welsh village of Fairbourne was already scheduled to be abandoned by Gwynedd Council in the 1950s after it announced it would no longer maintain its sea defenses.
Millions of people around the world live on coasts and will either have to “build around” the threat or be “abandoned”, said Dr Naughten, who added that controlling emissions would result in a slower sea level rise, which would give people more time to adapt.
For the current study, the BAS team of Dr. Naughten simulated four scenarios for the current century against a historical baseline of the previous one, imagining that emissions are either controlled to limit global temperature rise to 1.5 or 2 degrees above pre-industrial levels, or that emissions remains at a medium or high level.
Each scenario showed widespread warming of the Amundsen Sea, which borders West Antarctica, resulting in accelerated melting of the ice caps.
For the current study, the BAS team of Dr. Naughten simulated four scenarios for the current century against a historical baseline of the previous one, imagining that emissions are either controlled to limit global temperature rise to 1.5 or 2 degrees above pre-industrial levels, or that emissions remains at a medium or high level
The different emission pathways did not show much difference until around 2045, when the high-emissions simulation started to increase the rate of melting faster than the other scenarios.
Other scientists cautioned against taking the study’s results as absolutely conclusive as they are based on a single model, but that it is in line with other similar studies.
Professor Alberto Naveira Garabato, oceanographer at the University of Southampton, said: ‘This is a sobering study.
‘It illustrates how our past choices have likely committed us to substantial melting of the West Antarctic Ice Sheet and resulting sea level rise – to which we as a society will inevitably have to adapt in the coming decades and centuries.
‘However, it should also be a wake-up call. We can still save the rest of the Antarctic ice sheet, which contains about ten times as many feet of sea level rise, if we learn from our past inaction and start reducing greenhouse gas emissions now.”