Scientists ran a simulation on the UK’s national supercomputer to investigate the ocean-induced melting of the West Antarctic ice sheet: How much of it is inevitable and needs to be adapted to, and how much of the melting is still controlled by the international community through the greenhouse? reducing gas emissions.

They found no significant difference between intermediate emissions scenarios and the most ambitious targets of the 2015 Paris Agreement, accounting for climate variability such as El Niño. Even in the best-case scenario, where global temperatures rise by 1.5°C, melting would occur three times faster than in the 20th century.

The West Antarctic Ice Sheet is losing ice and is the largest source of Antarctic sea level rise. Previous modeling had found that this loss could be due to warming of the Southern Ocean, particularly the Amundsen Sea region. The West Antarctic Ice Sheet contains enough ice to raise global mean sea level by up to five metres.

Millions of people around the world live near coasts, and these communities will be greatly affected by sea level rise. A better understanding of future changes will allow policymakers to plan ahead and adapt more easily.

Published in the journal “The Inevitable Future Melt of the West Antarctic Ice Shelf in the 21st Century” Nature Climate Change.

Lead author Dr. D., a researcher at the British Antarctic Survey. Caitlin Naughten said: ‘We appear to have lost control of the melting of the West Antarctic Ice Sheet. If we want to preserve it in its historical form, we need to take action. A few decades ago about climate change. The good thing is that by recognizing this situation in advance, the world will have more time to adapt to impending sea level rise. “If you need to abandon a coastal area or significantly redevelop it, having the 50-year commitment will make a big difference.”

The team modeled one historical 20th century scenario as well as four future 21st century scenarios. Future scenarios will either lock global temperature increases at the 1.5°C and 2°C targets of the Paris Agreement or stick to standard scenarios of medium and high carbon emissions.

All scenarios led to significant and widespread future warming of the Amundsen Sea and increased melting of ice shelves. The three lower-range scenarios followed nearly identical paths throughout the 21st century. Even in the best-case scenario, warming of the Amundsen Sea accelerated by about three times, followed by the melting of the floating ice shelves that stabilized the inland glaciers, but these began to stabilize towards the end of the century.

In the worst-case scenario, melting on the ice shelf was greater than the others, but this only happened after 2045. The authors note that this high fossil fuel scenario, in which emissions increase rapidly, is considered unlikely.

This study provides serious future predictions for melting of the Amundsen Sea Ice Shelf but does not underestimate the importance of mitigation to limit the effects of climate change.

Naughten warns: “We must not stop working to reduce our dependence on fossil fuels. What we do now will help slow the rate of sea level rise in the long term. “The slower sea level changes occur, the easier it will be for governments and society to adapt, even if they cannot be stopped.”