Antarctic snowfall could affect short-term sea level rise

Earth's climate is extremely complex, and Antarctica is one of the important engines regulating changes in the planet over thousands of years. The most important reason for this is the huge ice sheet miles deep on the frozen continent. This massive reservoir has a major impact on sea levels around the world, so understanding the dynamics of how ice accumulates and enters the sea as icebergs is important.

According to modern computer models, the most important factors in how Antarctic ice affects sea level are ocean currents and temperature, which determine long-term sea level rise, but there are also short-term factors, such as snowfall.

By looking at snowfall rates at the Amundsen Sea Wall in West Antarctica, the BAS team determined that, although insignificant compared to larger long-term effects, changes in snowfall could have significant short-term effects on the region's mass balance, thereby affecting Sea level has significant short-term impacts.

Essentially, it's a question of how much snow falls in a given period. When ice falls into the sea, it adds more water, so sea levels rise. If snowfall is small, there will be a net loss of ice in Antarctica and greater sea level rise. However, if the snowfall is heavy, then the pack ice will accumulate faster than the peaks will collapse, so the net excess of ice and sea level rise will slow down.

In the case of the Amundsen Bay, it has lost about 331,1996 gigatons of ice (enough to bury London to a depth of 2 kilometers (1.24 miles)) since 1996, causing global sea levels to rise by about 9.2mm. It is worth noting that this change is not consistent. Snow droughts occurred between 2009 and 2013, during which time the region's contribution to sea level rise was 25 percent higher than in an average year, based on models based on data collected from 1996 to 2021. In contrast, between 2019 and 2020, heavy snowfall caused sea levels in the region to rise by half their normal levels.

"Changes in ocean temperature and circulation appear to be driving long-term large-scale changes in the mass of the West Antarctic (sic) ice sheet," said Dr Ben Davison, an Earth observation researcher at the University of Leeds and lead author of the study. "We definitely need to do more research because they may control the overall sea level rise and fall in West Antarctica."

"However, we were really surprised to see periods of extremely low or high snowfall affecting the ice sheet over a period of two to five years, so much so that we thought they could play a fairly important role in controlling the rate of ice loss in West Antarctica."

The study was published in Nature Communications .

Article source: British Antarctic Survey