Antarctic Snowfall May Not Limit Sea-Level Rise Or Global Warming

Even though experts feel that global warming might raise the planet's oceans in the next few decades, many indicate that heavy snowfall over Antarctica could stop the process. However, University of Washington researchers have arrived at another conclusion.

As warmer air can be more humid, it may create more snow inland and also rebuild the glacier, says climate model projections. Authors of the current paper looked at the data from the West Antarctic Ice Sheet Divide ice core to give an insight into the variation in the continent's snowfall over 31,000 years.

"It's allowed us to look at the snow accumulation back in time in much more detail than we've been able to do with any other deep ice core in Antarctica," said T.J. Fudge of the University of Washington and lead author of the study. "We show that warmer temperatures and snowfall sometimes go together, but often they don't."

The team found that before 8,000 years ago, even as the earth emerged from its last ice age, air temperatures rose with no indication of any rise in the snowfall.

"Our results make it clear that we cannot have confidence in projections of future snowfall over Antarctica under global warming," said Eric Steig, a University of Washington professor and co-author of the study.

Even though climate models show that warmer temperatures can increase the snowfall in Antarctica, new data says that temperature is not a reliable indicator.

"Depending on what part of the record you look at, you can draw different conclusions," Fudge said. "During some of the more abrupt climate changes, from when we had ice sheets to our current climate state, there's actually no relationship between temperature and snowfall."

The variation in the relationship may arise from atmospheric patterns such as winds that play a big role in the temperature of the continent as well as its sea ice, especially on short timescales.

"For sea-level rise, we're not really interested in what happens over thousands of years," Fudge said. "We're interested in what happens over the next few hundred years. At that shorter timescale, the variability in how the storms reach the continent matters much more than a few degrees of warming."

The impact of winds on Antarctic weather and its link to sea-level rise can be understood better by scientists with the current information.

"By getting models to better capture the variability in our snowfall record, we actually will get a better idea of how the warm ocean is going to interact with the ice sheets at the edge, and those will have an even bigger impact on sea level, eventually," Fudge said.

The findings published in the April 28 issue of the journal Geophysical Research Letters.