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Global warming: Greenland, West Antarctic ice sheets losing volume at record pace

Loss of ice volume doubles in just 5 years

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Arctic and Antarctic ice sheets are losing volume at a record pace. bberwyn photo.

By Bob Berwyn

FRISCO —Detailed new data from satellites and other sources show the world’s major ice sheets losing volume at a record pace, faster than at any time since satellite measurements started about 20 years ago.

Since 2009, the rate of volume loss from the Greenland Ice Sheet has doubled, and the rate of volume loss from the West Antarctic Ice Sheet has tripled, according to the new findings from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research. Continue reading

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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: Study sheds new light on Antarctic sea ice expansion

Growth in sea ice may be slower than reported

The water in the Antarctic Sound can be smooth as glass, and sometimes look thick and oily, probably because it's so cold. Click on the photo to learn about some of the environmental issues in Antarctica.

Scientists are puzzling over the expansion of Antarctic sea ice. bberwyn photo.

Staff Report

FRISCO — Global warming deniers have long been using the observed expansion of Antarctic sea ice as a way to try and confuse the public about the reality of global warming, but some new research by scientists with the Scripps Institution of Oceanography at University of California San Diego suggests the rate of expansion is not as dramatic as reported.

The findings, published in The Cryosphere (European Geosciences Union) acknowledge that there has been some expansion recently, but that some of the reported ice gain may be due to inconsistencies in computer models used to measure Antarctic sea ice. 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

Climate: Genetic study takes nuanced look at historic penguin response to global warming

Gradual warmup after ice age was beneficial to many species, but rapid rate of current warming may be too much for the flightless birds

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Populations of chinstrap penguins are declining fast as sea ice melts around the Antarctic Peninsula. bberwyn photo.

By Summit Voice

* More Summit Voice stories and photos on penguins here.

FRISCO — A new genetic analysis of historic penguin populations in Antarctica offers a nuanced view of how the flightless birds responded to climate change during the past 30 years. The findings suggests that, between the last ice age and up to around 1,000 years ago, penguin populations expanded as ice retreated and global temperatures warmed.

But warming has accelerated the past few decades; now many species may be declining because ice is retreating too far and too fast, according to the researchers from the Universities of Southampton and Oxford, who looked at genetic diversity to recreate past population sizes. A report of the research is published in the journal Scientific Reports. Continue reading

Study tracks historic Antarctica meltdowns

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Reading the history of Antarctica’s ice sheets is helping climate scientists project the future.

Transition from glacial periods punctuated by sudden surges of ice melt and sea level rise

Staff Report

FRISCO — Even without the addition of heat-trapping greenhouse gases from fossil fuel combustion, the Antarctica ice sheets may be vulnerable to sudden collapse and melting. One such episode, about 14,600 years ago, is thought to have caused sea level to rise by more than 12 feet in just 100 years.

Scientists are racing to understand the dynamics of the Antarctic ice sheets because of the potentially significant consequences of rapid changes, and in one of the newest studies, they’ve traced some of the big iceberg calving events between about 19,000 and 9,000 years ago by analyzing deep sea sediment cores extracted from the region between the Falkland Islands and the Antarctic Peninsula. Continue reading

Scientists say predation is a key driver of steep drop in macaroni penguin populations in South Georgia Island

Macaroni penguin populations are declining on South Georgia Island. Photo via Wikimedia and the Creative Commons.

Macaroni penguin populations are declining on South Georgia Island. Photo via Wikimedia and the Creative Commons.

*If you’re coming here from Twitter, here’s the link to the honey bee story.

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Click for honey bee survey story!

Sorry about that, some copy/paste sticky keyboard hardware issues

 

An ecosystem in flux

By Bob Berwyn

FRISCO — Predation by giant petrels is probably a key driver of steeply declining macaroni penguin numbers on South Georgia Island, according to scientists with the British Antarctic Survey.

The 10-year study used electronic tags to monitor the seabirds at the remote site in the far South Atlantic Ocean near Antarctica. The macaroni penguin population on the South Atlantic island of South Georgia has declined by almost seventy per cent since the early 1980s.

“Penguins are facing rapid changes in their environment, but at South Georgia, in the southwest Atlantic, we found compelling evidence that predators are the most important factor influencing the survival of chicks as they leave the colony for the first time,” lead author Catharine Horswill said. “This is a big leap forward as we had no idea that predation could be such a strong driving force. Knowing what drives survival rates of penguins puts us in a much better place to predict how these populations may change in the future.”

Continue reading

Climate: Antarctic ice melting faster than ever

New satellite data details rate of melting

Yes, there is still lots of ice in Antarctica, but it's melting faster than ever. bberwyn photo.

Yes, there is still lots of ice in Antarctica, but it’s melting faster than ever. bberwyn photo.

Staff Report

FRISCO — Yet another major study — the third within a week — confirms that the Antarctic ice sheets are going to big factors in the rise in sea level during the next few decades.

Led by scientists from the University of Leeds, the study shows that Antarctica is losing about 159 billion tons of ice each year — twice as much as during the last detailed survey. The latest assessment relied on detailed measurements of ice sheet elevation change from data collected by the European Space Agency’s CryoSat-2 satellite mission, which carries an altimeter specially designed for this task. Continue reading

Climate: West Antarctic Ice Sheet is in trouble

Meltdown is inevitable …

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New findings require upward revision of sea level rise estimates. bberwyn photo.

By Summit Voice

FRISCO — Scientists say it’s only a matter of time before a huge chunk of the West Antarctic Ice Sheet melts into the ocean, potentially raising sea level around the world by several feet.

“The collapse of this sector of West Antarctica appears to be unstoppable,” said glaciologist Eric Rignot, a UC Irvine Earth system science professor who is also with NASA’s Jet Propulsion Laboratory. “The fact that the retreat is happening simultaneously over a large sector suggests it was triggered by a common cause, such as an increase in the amount of ocean heat beneath the floating parts of the glaciers. At this point, the end appears to be inevitable.” Continue reading

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