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Polar Warning: Even Antarctica’s Coldest Region Is Starting to Melt

April 9, 2019

Melting ice on the coast of Adélie Land in East Antarctica.
Melting ice on the coast of Adélie Land in East Antarctica. REUTERS/PAULINE ASKIN

Polar Warning: Even Antarctica’s Coldest Region Is Starting to Melt

East Antarctica is the coldest spot on earth, long thought to be untouched by warming. But now the glaciers and ice shelves in this frigid region are showing signs of melting, a development that portends dramatic rises in sea levels this century and beyond. 

No place on Earth is colder than East Antarctica. Home to the South Pole and making up two-thirds of the southernmost continent, the vast ice sheets of East Antarctica — formed over tens of millions of years — are nearly three miles thick in places. The temperature commonly hovers around -67 degrees Fahrenheit (-55 degrees Celsius); in 2010, some spots on East Antarctica’s polar plateau plunged to a record-breaking -144 degrees F.

Now, however, parts of the East Antarctic are melting.

Research into what’s happening in East Antarctica is still in its early stages. It’s hard to decipher what exactly is taking place on a gigantic continent of ice with just a few decades of satellite data and limited actual measurements of things like snowfall and ocean temperatures. But according to one controversial paperreleased earlier this year, East Antarctica is now, in fact, shrinking, and is already responsible for 20 percent of the continent’s ice loss.

For decades, researchers considered this portion of the continent to be stable. While warming sea and air temperatures have caused ice shelves and glaciers in the lower-altitude, warmer western regions of the Antarctic to melt and collapse, the larger, colder East had seemed an untouchable behemoth. If anything, climate change was expected to bring more snow to its interior, making its ice sheets grow in size.

 …click on the above link to read the rest of the article…

How the World Passed a Carbon Threshold and Why It Matters

February 10, 2017

How the World Passed a Carbon Threshold and Why It Matters

Last year marked the first time in several million years that atmospheric concentrations of CO2 passed 400 parts per million. By looking at what Earth’s climate was like in previous eras of high CO2 levels, scientists are getting a sobering picture of where we are headed.

Last year will go down in history as the year when the planet’s atmosphere broke a startling record: 400 parts per million of carbon dioxide. The last time the planet’s air was so rich in CO2 was millions of years ago, back before early predecessors to humans were likely wielding stone tools; the world was a few degrees hotter back then, and melted ice put sea levels tens of meters higher.

“We’re in a new era,” says Ralph Keeling, director of the Scripps Institution of Oceanography’s CO2 Program in San Diego. “And it’s going fast. We’re going to touch up against 410 pretty soon.”

There’s nothing particularly magic about the number 400. But for environmental scientists and advocates grappling with the invisible, intangible threat of rising carbon dioxide levels in the atmosphere, this symbolic target has served as a clear red line into a danger zone of climate change.

When scientists (specifically, Ralph Keeling’s father) first started measuring atmospheric CO2 consistently in 1958, at the pristine Mauna Loa mountaintop observatory in Hawaii, the CO2 level stood at 316 parts per million (ppm), just a little higher than the pre-industrial level of 280 ppm. 400 was simply the next big, round number looming in our future.

But as humans kept digging up carbon out of the ground and burning it for fuel, CO2 levels sped faster and faster toward that target. In May 2013, at the time of the usual annual maximum of CO2, the air briefly tipped over the 400 ppm mark for the first time in several million years.

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How Climate Change Could Jam The World’s Ocean Circulation

September 10, 2016

How Climate Change Could Jam The World’s Ocean Circulation

Scientists are closely monitoring a key current in the North Atlantic to see if rising sea temperatures and increased freshwater from melting ice are altering the “ocean conveyor belt” — a vast oceanic stream that plays a major role in the global climate system.

Mariusz Kluzniak/Flickr
Melting ice flows into the northern Atlantic Ocean in eastern Greenland.
Susan Lozier is having a busy year. From May to September, her oceanographic team is making five research cruises across the North Atlantic, hauling up dozens of moored instruments that track currents far beneath the surface. The data they retrieve will be the first complete set documenting how North Atlantic waters are shifting — and should help solve the mystery of whether there is a long-term slowdown in ocean circulation. “We have a lot of people very interested in the data,” says Lozier, a physical oceanographer at Duke University.

A similar string of moorings across the middle of the Atlantic, delving as deep as 3.7 miles from the Canary Islands to the Bahamas, has already detected a disturbing drop in this ocean’s massive circulation pattern. Since those moorings were installed in 2004, they have seen the Atlantic current wobble and weaken by as much as 30 percent, turning down the dial on a dramatic heat pump that transports warmth toward northern Europe. Turn that dial down too much and Europe will go into a deep chill.

Researchers have been worried about an Atlantic slowdown for years. The Atlantic serves as the engine for the planet’s conveyor belt of ocean currents: The massive amount of cooler water that sinks in the North Atlantic stirs up that entire ocean and drives currents in the Southern and Pacific oceans, too. “It is the key component” in global circulation, says Ellen Martin, a paleoclimate and ocean current researcher at the University of Florida.

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Abrupt Sea Level Rise Looms As Increasingly Realistic Threat

May 7, 2016

Abrupt Sea Level Rise Looms As Increasingly Realistic Threat

Ninety-nine percent of the planet’s freshwater ice is locked up in the Antarctic and Greenland ice caps. Now, a growing number of studies are raising the possibility that as those ice sheets melt, sea levels could rise by six feet this century, and far higher in the next, flooding many of the world’s populated coastal areas. 

Christopher Michel/Flickr
West Antarctica’s glaciers and floating ice shelves are becoming increasingly unstable.
Last month in Greenland, more than a tenth of the ice sheet’s surface was melting in the unseasonably warm spring sun, smashing 2010’s record for a thaw so early in the year. In the Antarctic, warm water licking at the base of the continent’s western ice sheet is, in effect, dissolving the cork that holds back the flow of glaciers into the sea; ice is now seeping like wine from a toppled bottle.

The planet’s polar ice is melting fast, and recent satellite data, models, and fieldwork have left scientists sobered by the speed of the sea level rise we should expect over the coming decades. Although researchers have long projected that the planet’s biggest ice sheets and glaciers will wilt in the face of rising temperatures, estimates of the rate of that change keep going up. When the Intergovernmental Panel on Climate Change (IPCC) put out its last report in 2013, the consensus was for under a meter (3.3 feet) of sea level rise by 2100. In just the last few years, at least one modeling study suggests we might need to double that.

Eric Rignot at the University of California, Irvine says that study underscores the possible speed of ice sheet melt and collapse. “Once these processes start to kick in,” he says, “they’re very fast.”

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Olduvai IV: Courage
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Olduvai II: Exodus
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