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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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Climate study shows sea level can rise by 30 feet per century during ice cap meltdowns

If sea levels rose to where they were during the Last Interglacial Period, large parts of the Gulf of Mexico would be under water (red areas), including half of Florida and several Caribbean islands. Credit: Jeremy Weiss, Department of Geosciences, The University of Arizona.

If sea levels rose to where they were during the last Interglacial Period, large parts of the Gulf of Mexico would be under water (red areas), including half of Florida and several Caribbean islands. Credit: Jeremy Weiss, Department of Geosciences, The University of Arizona.

‘Once under way, this response may be irreversible for many centuries to come’

Staff Report

FRISCO — Melting ice caps caused global sea level to rise by up to 30 feet per century during the ending phases of the last five ice ages, researchers said, announcing results of a study that traces sea level fluctuations across a span of half a million years.

The record shows that sea level changes can happen quickly on a geological time scale, and that there were hundreds of smaller pulses in sea level in between the five major events. But the biggest changes in sea level happened after periods when ice sheets were much larger than today’s. 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

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

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: 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: Annual sea-level cycles intensifying along eastern Gulf Coast

Higher summer spikes could mean more destructive storm surges

Researchers have documented changes in the annual cycle of sea level changes along the Florida Gulf Coast. bberwyn photo.

Researchers have documented changes in the annual cycle of sea level changes along the Florida Gulf Coast. bberwyn photo.

By Summit Voice

FRISCO — Annual sea level fluctuations have been intensifying along parts of the Gulf Coast, raising concerns about more hurricane flooding and impacts to delicate coastal ecosystems in the region.

There have always been seasonal fluctuations in sea level, which rise in summer and fall in winter. But a new study shows that, from the Florida Keys to southern Alabama, those cycles have amplified in the past 20 years.

The additional summer sea level rise during the past two decades means storm surges can rise higher than previously thought, according to Thomas Wahl, a postdoctoral researcher from the University of Siegen in Germany who is working at the University of South Florida in St. Petersburg and lead author of the study. Continue reading

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