Posted by AzBlueMeanie:
National Geographic News reported this week, Polar Ice Sheets Shrinking Worldwide, Study Confirms:
The polar ice sheets are indeed shrinking—and fast, according to a comprehensive new study on climate change.
And the effects, according to an international team, are equally clear—sea levels are rising faster than predicted, which could bring about disastrous effects for people and wildlife.
Rising seas would increase the risk of catastrophic flooding like that caused by Hurricane Sandy last month in New York and New Jersey. Environmental damage may include widespread erosion, contamination of aquifers and crops, and harm to marine life. And in the long term, rising seas may force hundreds of millions of people who live along the coast to abandon their homes.
By reconciling nearly two decades of often conflicting satellite data into one format—in other words, comparing apples to apples—the new study, published in the journal Science, made a more confident estimate of what's called ice sheet mass balance.
That refers to how much snow is deposited on an ice sheet versus how much is lost, either due to surface melting or ice breaking off glaciers.
Between 1992—when polar satellite measurements began—and 2011, the results show that all of the polar regions except for East Antarctica are losing ice, said study leader Andrew Shepherd, a professor of earth observation at the University of Leeds in the U.K.
In that 20-year span, Greenland lost 152 billion tons a year of ice, West Antarctica lost 65 billion tons a year, the Antarctic Peninsula lost 20 billion tons a year, and East Antarctica gained 14 billion tons a year. (See an interactive map of Antarctica.)
"When we did the experiments properly using the same time periods and same maps, the riddles did all agree," Shepherd said.
According to glaciologist Alexander Robinson, "We've had a good idea of what the ice sheets are doing, but it seems this study really brings it all together in one data set that gives a much clearer picture.
"It's one more piece of supporting evidence that shows there are some dramatic changes happening, and we know that's being driven mainly by a warmer climate and warmer ocean—but there's still a lot we don't know about these regions and how they're changing," said Robinson, of the Complutense University of Madrid in Spain, who was not involved in the research.
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Overall, polar ice loss has contributed about 11.1 millimeters to global sea level since 1992—roughly 20 percent of the total global sea level rise during that period, according to the study.
What's more, a study published earlier this week in Environmental Research Letters shows that sea levels are rising at a rate of 3.2 millimeters a year. That's 60 percent faster than the latest estimate of 2 millimeters a year projected by the IPCC. (See sea level rise pictures.)
"These results should be a major concern for politicians and climate talks in Doha, as they show that global warming is real and having major consequences that will only get bigger over time," Trenberth said by email.
As the World Meteorological Organization put it in a report released Wednesday during this week's UN climate change talks in Doha, Qatar, "climate change is taking place before our eyes." (See a map of global warming impacts worldwide.)
In addition to displacing millions, sea level rise may also supercharge large storms. For example, when a storm like Hurricane Sandy makes landfall, higher seas may boost storm surges that can strip away everything in their path and create damaging floods.
The award winning documetary film "Chasing Ice" is coming soon to The Loft Theater in Tucson on Friday, December 14. Chasing Ice | The Loft Cinema:
Co-presented by the University of Arizona's Institute of the Environment
Featuring a special introduction by the Institute of the Environment on opening night, Friday, December 14th at 7:30 p.m.
Acclaimed National Geographic photographer James Balog was once a skeptic about climate change. But through his Extreme Ice Survey (EIS), he discovers undeniable evidence of our changing planet. In Chasing Ice, Balog deploys revolutionary time-lapse cameras to capture a multi-year record of the world's changing glaciers. His hauntingly beautiful videos compress years into seconds and capture ancient mountains of ice in motion as they disappear at a breathtaking rate. Traveling with a team of young adventurers across the brutal Arctic, Balog risks his career and his well-being in pursuit of the biggest story facing humanity. As the debate polarizes America, and the intensity of natural disasters ramps up globally, Chasing Ice depicts a heroic photojournalist on a mission to deliver fragile hope to our carbon-powered planet. (Dir. by Jeff Orlowski, 2012, US, 75 min., Rated PG-13, Submarine Films) HD Digital