Increasing melting of the West Antarctica ice sheet is inevitable Sciences

The slower sea level changes slow, the easier it is for governments and society to adapt to them, even if they cannot be stopped.

A team of scientists ran simulations on the UK’s National Supercomputer to investigate the melting of the West Antarctic ice sheet, to explore how much melting is unavoidable, must be adapted to, and how much melting can still be controlled by the international community. Reducing greenhouse gas emissions, taking into account climate fluctuations such as the El Niño phenomenon.

The research team from the British Antarctic Survey found no significant difference between medium-term emissions scenarios and the more ambitious targets in the 2015 Paris Agreement.

As the agency’s press release notes, even under the best-case scenario of a global temperature rise of just 1.5 degrees Celsius, ice melt will increase three times faster than in the 20th century.

It seems we have lost control

Combined, the West Antarctica ice sheet contains enough ice to raise global average sea level by up to 5 metres. What is dangerous is that we are losing this ice layer, and previous models have found that this loss could be caused by a rise in the temperature of the Southern Ocean, especially the Amundsen Sea region.

Because millions of people around the world live near the coast, these communities will be greatly affected by sea level rise. Hence, a better understanding of future changes would allow policy makers to plan and adapt more easily.

“We appear to have lost control of the melting of the West Antarctic Ice Sheet, and if we had wanted to preserve it in its historical condition, we would have taken action on climate change decades ago,” says Dr. Caitlin Naughton, lead author of the study published in the journal Nature Climate Change.

She adds that the silver lining is that by acknowledging this situation in advance, the world will have more time to adapt to the coming sea level rise. “If you need to abandon or significantly redesign a coastal area, 50 years in front of you will make all the difference,” he said.

Simulate scenarios

The team simulated 4 future scenarios for the 21st century, in addition to one historical scenario for the 20th century. The future scenarios were either to hold the global temperature rise at the goals set by the Paris Agreement, which are between 1.5 degrees Celsius and 2 degrees Celsius, or to follow the standard scenarios for medium and high carbon emissions.

All scenarios lead to significant and widespread future warming of the Amundsen Sea and increased melting of its ice shelves. The three lower-range temperature scenarios followed almost identical trajectories during the 21st century.

Even under the best-case scenario, the warming of the Amundsen Sea accelerated by about a factor of three, followed by the melting of the floating ice shelves that stabilize the inland glaciers, although they began to flatten by the end of the century.

The worst-case scenario was for the ice shelf to melt, but only after 2045. However, the authors note that this high-fossil fuel scenario, where emissions increase rapidly, is considered unlikely to happen.

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