British Antarctic Snowfall Study Deepens the Mystery of Global Warming

Previous climate change models predicted that global sea levels would rise by a meter by the year 2100 due in part to melting Antarctic ice, but those estimates have proven to be flawed.

Over the past century, the Antarctic has gone from being a vast Terra Incognita to a continent-sized ticking time bomb: according to NASA, Antarctica has lost “approximately 125 gigatons of ice per year [between 2002 and 2016], causing global sea level to rise by 0.35 millimeters per year.”

If global temperatures continue to rise, Antarctica’s melting glaciers will cause the oceans to rise, as well as drastic changes in climate. However, new research by British Antarctic Survey shows that Antarctica paradoxically saw a 10 percent increase in snowfall over the last 200 years.

The research comes from 79 ice core samples collected across the continent, and the estimated increase in snow represents about 272 giga tonnes of water.

“There is an urgent need to understand the contribution of Antarctic ice to sea-level rise and we use a number of techniques to determine the balance between snowfall and ice loss,” said lead author on the study, Dr. Liz Thomas.

“When ice loss is not replenished by snowfall then sea level rises…Our new results show a significant change in the surface mass balance [from snowfall] during the 20th century. The largest contribution is from the Antarctic Peninsula, where the annual average snowfall during the first decade of the 21st century is 10 percent higher than at the same period in the 19th century.”

The increase in snowfall doesn’t contradict previous estimates of ice loss around Antarctica’s coast, but it does make the picture more complicated.

Previous climate change models, proposed in 2013, predicted that global sea levels would rise by a meter by the year 2100 due in part to melting Antarctic ice, but those estimates have proven to be flawed.

Dr. Thomas echoes the advice of Tim Naish, who acknowledged that the Antarctic is an important factor in climate change, but still a poorly understood one:

“There is an international effort to create computer simulations of future sea-level rise in a warming world. It is complex and challenging for scientists to fully understand and interpret changes in the ice that we see happening today. We know that the two major influencers affecting change—the mass gain (from snowfall) and the mass loss (from melt)—are acting differently from one another. Our new findings take us a step towards improving our knowledge and understanding.”

Full post

via The Global Warming Policy Forum (GWPF)

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April 10, 2018 at 01:29AM

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