Scientists saw a nearly unheard of Antarctic meltdown
A new study published in Nature Communications only adds to the disturbing trend of change afoot in Antarctica. Researchers have documented rain on a continent more known for snow and widespread surface melt in West Antarctica last summer, one of the most unstable parts of a continent that’s already being eaten away by warm waters below the ice.
The findings, published Thursday, indicate that last year’s super El Niño played a large role in driving the meltdown, but researchers are concerned that overlaying natural climate patterns onto the long-term warming driven by carbon pollution could put Antarctica’s ice in an even more precarious position.
“There’s a substantial loss of ice going on from warm water eating away at the bottom of some critical ice shelves,” David Bromwich, a climate modeler at Ohio State, said. “If we move into the future and we’ve got a lot of melting from the top as well, that means things would proceed even faster. It’s not a good prescription.”
The research, which Bromwich helped produced, stemmed from a series of coincidences starting at the top of the West Antarctic ice sheet, nearly 6,000 feet above sea level. Researchers stationed there in January 2016 noticed surface melt starting in the middle of the month and even reported seeing rain as warm, moist air poured into the region.
Bromwich said he had never heard of rain falling on that region of the ice sheet, though the Antarctic Peninsula further north will occasionally get a few showers. His and other researchers’ curiosity was piqued and using satellite imagery and high altitude balloon data, they were able to confirm the melt not just at the top of the ice sheet but across much of West Antarctica.
About 300,000 square miles of the ice sheet near the Ross Sea experienced melt, making it the second-largest surface melt ever documented in that region of Antarctica. The meltdown was caused by incredibly mild air, which saw temperatures spike up to 27°F (15°C) compared to early January, pushing them above freezing for a two-week period at lower elevations of the ice sheet.
The biggest driver of the Antarctic heat wave was the super El Niño, then at its peak in the tropical Pacific. It helped rearrange the atmosphere so a high pressure system off Chile’s coast could steer abnormally balmy weather toward West Antarctica. The pattern has played out in other El Niño years, causing similar widespread melt events.
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