New relationship between greenhouse gases and sea level rise

MADRID, 6 Apr. (EUROPE PRESS) –

A new study provides the first evidence that the increase in greenhouse gases produces long-term warming in the Amundsen Sea in West Antarctica.

Scientists from the British Antarctic Survey (BAS) point out that, although others have proposed this relationship, no one had been able to prove it.

Ice loss from the West Antarctic Ice Sheet into the Amundsen Sea is one of the fastest and most worrying contributions to global sea level rise. If the West Antarctic Ice Sheet were to melt, global sea level might rise up to three meters.

Ice loss patterns suggest that the ocean may have warmed in the Amundsen Sea over the last hundred years, but scientific observations of the region did not begin until 1994.

In the study, published in the journal ‘Geophysical Research Letters’, Oceanographers used advanced computer models to simulate the ocean’s response to a series of possible changes in the atmosphere between 1920 and 2013.

Simulations show that the Amundsen Sea warmed overall throughout the century. This warming corresponds with simulated trends in wind patterns in the region, which increase temperatures by driving currents of warm water into and below the ice.

Increased greenhouse gases are known to make these wind patterns more likely, so it is believed that the trend of the winds is caused in part by human activity.

This study supports theories that ocean temperatures in the Amundsen Sea have been rising since before records began. It also provides the missing link between ocean warming and wind trends, which are known to be driven in part by greenhouse gases.

Ocean temperatures around the West Antarctic Ice Sheet will likely continue to rise if greenhouse gas emissions increase, with consequences for melting ice and global sea level. However, these results suggest that this trend might be curbed if emissions are sufficiently reduced and wind patterns stabilize in the region.

Dr Kaitlin Naughten, BAS ocean ice modeller and lead author of this study, says her simulations show how the Amundsen Sea responds to long-term trends in the atmosphere, specifically westerly winds in the southern hemisphere.

“This raises concerns for the future because we know that these winds are affected by greenhouse gases. –continues in a statement–. However, it should also give us hope, because it shows that sea level rise is not out of our control.”

For his part, Professor Paul Holland, a scientist specializing in oceans and ice at BAS and co-author of the study, stresses that “changes in westerly winds in the southern hemisphere are a well-established climate response to the effect of greenhouse gases. However, the Amundsen Sea is also subject to strong natural climate variability.”

“Simulations suggest that both natural and anthropogenic changes are responsible for ocean-driven ice loss from the West Antarctic Ice Sheet.”