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Archive for the ‘CRYOSPHERE’ Category

Earth’s poles are shifting because of climate change

“Climate change is causing the North Pole’s location to drift, owing to subtle changes in Earth’s rotation that result from the melting of glaciers and ice sheets.

Computer simulations had suggested that the melting of ice sheets and the consequent rise in sea level could affect the distribution of mass on the Earth’s surface. This would in turn cause the Earth’s axis to shift, an effect that has been confirmed by measurements of the positions of the poles.

Jianli Chen of the University of Texas at Austin and colleagues have shown that melting due to our greenhouse-gas emissions is making its own contribution to the shift. …”Ice melting and sea level change can explain 90 per cent of the [eastward shift],” says Chen. “The driving force for the sudden change is climate change.””

More to Lose Than You Think When Sea Ice Is Lost

“The Arctic has warmed twice as fast as the rest of the globe in the past two decades. Sea ice in this region is melting into the ocean so rapidly that its rate exceeds most model projections. The consequences of a world with less sea ice, argue the authors of this Review, include amplification of the warming phenomenon: less sea ice means fewer surfaces to reflect sun back into the atmosphere. Thus, loss of sea ice is not just an indicator of warming, but a contributor to it as well.

Read more about this research from the 2 August issue of Science here.”

Greenland’s ice sheets are disappearing faster than anyone predicted

“Climatologist Jason Box has a radical theory why…

In 2009, he announced the Petermann glacier, one of the largest in Greenland, would break up that summer – a potent sign of how fast the Arctic was warming. Most glaciologists thought he was nuts – especially after the summer passed and nothing happened. In 2010, however, Petermann began to calve; two years later, it was shedding icebergs twice the size of Manhattan. Another example: In early 2012, Box predicted there would be surface melting across the entirety of Greenland within a decade. Again, many scientists dismissed this as alarmist claptrap. If anything, Box was too conservative – it happened a few months later. He also believes that the climate community is underestimating how much sea levels could rise in the coming ­decades.

…Box decided to return to Greenland this summer – his 24th trip here in the past 20 years – to test a more startling hypothesis, part of what he calls “a unified theory” of glaciology: that tundra fires in Canada, massive wildfires in Colorado and pollution from coal-fired power plants in Europe and China had sent an unexpectedly thick layer of soot over the Arctic region last summer, which settled onto Greenland’s vast frozen interior, increasing the amount of sunlight the snow and ice absorbed, which in turn accelerated the melting.”

Ice sheets melting at poles faster than before

“Fueled by global warming, polar ice sheets in Greenland and Antarctica are now melting three times faster than they did in the 1990s, a new scientific study says.”

Why seas are rising ahead of predictions

“Sea levels are rising faster than expected from global warming, and University of Colorado geologist Bill Hay has a good idea why. The last official IPCC report in 2007 projected a global sea level rise between 0.2 and 0.5 meters by the year 2100. But current sea-level rise measurements meet or exceed the high end of that range and suggest a rise of one meter or more by the end of the century.

“What’s missing from the models used to forecast sea-level rise are critical feedbacks that speed everything up,” says Hay. He will be presenting some of these feedbacks in a talk on Sunday, 4 Nov., at the meeting of The Geological Society of America in Charlotte, North Carolina, USA.

One of those feedbacks involves Arctic sea ice, another the Greenland ice cap, and another soil moisture and groundwater mining.”

Thawing permafrost frees millions of tons of carbon: study

“…atmospheric warming and coastal erosion are gnawing at the icy seal, releasing about 40 million tonnes of carbon a year –10 times more than previously thought, said a study in the journal Nature.”

Sea ice melt is faster than predicted in worst-case climate models

“The melt was faster than even predicted in worst-case climate models, according to Michael E. Mann, an earth scientist at Penn State University who was the lead author of a major United Nations report in 2001 on climate change. “The sea ice decline is perhaps the most profound of those cautionary tales because the models have basically predicted that we shouldn’t see what we’re seeing now for several decades,” Mann said.”

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