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Climate: Southern Ocean layering could lead to big Antarctica meltdown along with surge in sea level rise

‘The big question is whether the ice sheet will react to these changing ocean conditions as rapidly as it did 14,000 years ago’

The ice fields of Antarctica

The ice fields of Antarctica. bberwyn photo.

Staff Report

FRISCO — A stratification of the ocean around Antarctica could lead to more rapid melting of ice sheets, triggering a sudden surge in sea level rise. That last time that happened was well before the global warming era, about 14,000 years ago, but scientists are now seeing signs of a similar pattern.

A new study found that in the past, when ocean temperatures around Antarctica became more layered, with a warm layer of water below a cold surface layer,  ice sheets and glaciers melted much faster than when the cool and warm layers mixed more easily. This defined layering of temperatures is exactly what is happening now around the Antarctic.

“The reason for the layering is that global warming in parts of Antarctica is causing land-based ice to melt, adding massive amounts of freshwater to the ocean surface,” said ARC Centre of Excellence for Climate System Science researcher Prof Matthew England, an author of the paper, published in Nature Communications.

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Study shows why Penguins need more protection

‘If we don’t worry about the imminent threats now, it’s probably not worth worrying about the medium-term future’

Gentoo penguins and the S/V Professor Molchanov at sea.

Gentoo penguins and the S/V Professor Molchanov. bberwyn photo.

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A penguin dives in and out of the icy waters near the Antarctic Peninsula. bberwyn photo.

By Bob Berwyn

FRISCO — The world’s penguins could use a little help, a team of  leading conservation biologists said last month, announcing results of a study that systematically assessed global risks to the southern hemisphere sea birds.

While global warming remains a long-term threat, other impacts, primarily related to human activities, are a more clear and present danger, the scientists said, advocating for a more widespread network of marine protected areas to buffer penguins from pollution, tourism and fishing.

“We need to address some of these issues before we think about resilience to climate change,” said Dr. Phil Trathan, head of conservation biology with the British Antarctic Survey. “If we don’t worry about the imminent threats now, it’s probably not worth worrying about the medium-term future,” Trathan said, explaining that penguins living and breeding in southern Africa and South America face the highest risks.

“If you want to create resilient populations, deal with some of the immediate threats, and where the threats are most evident is where penguins inhabit areas close to mankind,” he said. Continue reading

Climate study shows how melting ice is raising sea level around Antarctica

‘The interaction between air, sea and ice in these seas is central to the stability of the Antarctic Ice Sheet and global sea levels’

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A new study tracks global warming impacts around Antarctica. bberwyn photo.

By Summit Voice

FRISCO — Global warming is upsetting the delicate balance between Antarctic ice, air and sea, University of Southampton scientists said this week, releasing results of a study showing a rapid rise in sea level around the frozen continent.

Based on an analysis of 19 years worth of satellite data, the researcher said sea level around the coast of Antarctica has climbed 2 centimeters more than the global average, driven almost entirely by an increase in freshwater, which is less dense than saltwater. That can cause localized increases in sea level, said Craig Rye, lead author of the paper published in the journal Nature Geoscience. Continue reading

Antarctica: Life beneath the ice

Antarctic peak.

Science mission finds microbial life beneath Antarctic ice sheets. bberwyn photo.

Simple organisms process basic elements to survive

Staff Report

FRISCO —Tiny organisms living beneath the vast Antarctic ice fields can convert ammonium and methane into the energy required for growth, surviving in one of the most unlikely environments on Earth, according to scientists who studied a subsurface lake that hasn’t seen sunlight for millions of years.

“We were able to prove unequivocally to the world that Antarctica is not a dead continent,” said Montana State University professor John Priscu, the chief scientist of the U.S. project called WISSARD that sampled the sub-ice environment. Continue reading

Climate: Melting Antarctic ice sheets likely to become big factor in sea level rise sooner than thought

‘Official’ IPCC sea level estimates may be too low

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Antarctica ice is becoming a bigger factor in global sea level rise. bberwyn photo.

By Bob Berwyn

FRISCO — Although Antarctica’s vast ice sheets are only a small factor in global sea level rise right now, that’s likely to change in coming decades, scientists said after a new analysis of ocean temperatures around the frozen continent.

“If greenhouse gases continue to rise as before, ice discharge from Antarctica could raise the global ocean by an additional 1 to 37 centimeters in this century already,” says lead author Anders Levermann, with the Potsdam Institute for Climate Impact Research. “Now this is a big range – which is exactly why we call it a risk: Science needs to be clear about the uncertainty, so that decision makers at the coast and in coastal megacities like Shanghai or New York can consider the potential implications in their planning processes,” says Levermann.

The scientists analyzed how rising global mean temperatures resulted in a warming of the ocean around Antarctica, thus influencing the melting of the Antarctic ice shelves. The marine ice sheets in West Antarctica alone have the potential to elevate sea level by several meters – over several centuries. Continue reading

Climate change drives Antarctic fur seal decline

Fur seals on Half Moon Island, in the South Shetland chain, off the Antarctic Peninsula. PHOTO BY BOB BERWYN.

Fur seals on Half Moon Island, in the South Shetland chain, off the Antarctic Peninsula. bberwyn photo.

Survival of the fittest?

By Summit Voice

FRISCO — After studying fur seals around Antarctica for decades, researchers with the British Antarctic Survey say they’re seeing distinct genetic changes related to a changing climate and food availability. But despite a shift  towards individuals more suited to changing environmental conditions, this fitness is not passing down through generations, leaving the fur seal population on South Georgia Island in decline. Continue reading

Climate: Are emperor penguins doomed?

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Emperor penguins in Antarctica. Photo courtesy BAS.

New study projects 50 percent decline by century’s end as sea ice habitat dwindles

Staff Report

FRISCO — Antarctica’s emperor penguins may be colonizing new territory right now, but the long-term outlook for the birds is grim, according to new research showing that changes in sea ice concentration will likely cause most colonies to decline by 50 percent by the end of the century.

Even the most remote reaches of Antarctica won’t be immune to the changes, the study leaders said, describing the results of their findings in a new article in the journal Nature Climate Change.

The study concludes that emperor penguins are fully deserving of an endangered species listing based on global warming threats. The research will help inform federal bio-crats as they ponder a listing under the Endangered Species Act. Continue reading

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