Increasing Snowfall in Antarctica Could Slightly Reduce Sea Level Rise

Snowfall across the great white continent of Antarctica is increasing, according to a study released this week by an international team led by the British Antarctic Survey.

The team analyzed 79 ice cores from across Antarctica that provide detailed information on how much snow has fallen over hundreds of years, and it found a 10% increase in snowfall over the past two centuries.

This contradicts studies that found that Antarctic snowfall has remained largely constant over the past several decades to centuries. But those studies analyzed only a few ice cores, whereas this comprehensive look at the continent gives a much more thorough view of how weather patterns have changed the polar weather.

“The snowfall increase is driven by changing circulation patterns, drawing warm moist air from the mid-latitudes,” said lead study author Liz Thomas, an ice scientist with the British Antarctic Survey.

As you probably guessed, global warming is behind those changing circulation patterns, heating the air and water and reducing sea ice.

“Warming surface temperatures and reduced sea ice in the sea adjacent to the Antarctic Peninsula is resulting in increased moisture availability,” Thomas said.

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This available moisture allows for additional snowfall, especially in the Antarctic Peninsula where snowfall has increased the most, according to the ice core data.

Why do we care about snowfall patterns in a part of the world where almost no one lives? Knowing the net gain or loss of water from the ice sheets is critical in projecting how much sea levels will rise in the next several decades and beyond.

We know that ice is melting from the ice sheets and flowing into the sea, raising its levels — but this amount is lessened by how much snow is falling back onto the continent.

“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,” Thomas said.

“When ice loss is not replenished by snowfall, then sea level rises.”

Put simply, more snowfall means less sea level rise.

The results of the new study indicate that the increased snowfall over Antarctica will have to be worked into the sea level rise projections and will lower them just a bit.

The 10% increase in snowfall over the past two centuries equates to about 272 gigatons of water more being deposited as snow over Antarctica every year — or about double the volume of the Dead Sea.

But don’t go investing in oceanfront property based on this information just yet.

The overall reduction of sea level from the increasing snowfall is projected to be just 0.04 millimeters per decade.

Current rates of global sea level rise, according to NASA’s climate page, are 3.2 millimeters per year, or 32 millimeters per decade, meaning the reduction from Antarctic snowfall corresponds to about a tenth of 1% of the overall amount that the sea level is rising due to global warming.

Put another way, “the increased snowfall in Antarctica approximately offsets the contribution to sea level caused by the melting Patagonian ice fields in the past 200 years,” Thomas said.

Although it’s certainly important in understanding the changing dynamics in Antarctica, the new information doesn’t even make a dent in the overall projections of sea level rise that threaten major cities around the globe in the next few decades.