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Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory
About 40 percent of Greenland's ice sheet thawed at or near the surface on July 8. Four days later, the melt had dramatically accelerated and an estimated 97 percent of the ice sheet surface had thawed.
Three satellites found that 97 percent of Greenland -- the land mass second only to Antarctica for its volume of ice -- underwent a thaw never before seen in 33 years of satellite tracking, NASA reported Tuesday.
Satellite experts at first didn't trust their readings, especially since they showed an incredible acceleration. Over four days, Greenland's ice sheet -- which covers 683,000 square miles -- went from 40 percent in thaw to nearly entirely in thaw.
"This was so extraordinary that at first I questioned the result: Was this real or was it due to a data error?" Son Nghiem of NASA's Jet Propulsion Lab in Pasadena, Calif., said in NASA's statement about the findings.
Scientists on the ground in Greenland had been reporting an unusually warm summer thaw, including damage at a snow airfield and strong runoff threatening a bridge, Tom Wagner, who manages NASA's ice research programs, told NBC News.
Ice cores from Greenland's highest region do reveal that such island-wide thaws have happened every 150 years or so, at least over the last few thousand years, but the fear now is that it might occur much more frequently due to warming sea and air temperatures.
"We can't lose sight of the fact that Greenland's ice sheet is losing 150 gigatons of ice a year," Wagner said. That translates into raising sea levels by one-one hundredth of an inch. Additionally, the danger of greater warming and greater melt persists.
"If we continue to observe melting events like this in upcoming years, it will be worrisome," said Lora Koenig, a NASA glaciologist who helped analyze the satellite data.
Monitoring stations on land "showed temperatures above freezing, confirming that the surface was melting for the entire ice sheet," Konrad Steffen, director of the Swiss Federal Institute for Forest, Snow and Landscape Research, told NBC News.
Since then, he added, "temperatures have fallen below freezing for the higher elevations but still are melting below 1500 meters."
The director of the top ice research center in the U.S. said the discovery fits into "the larger picture of a strongly warming Arctic."
A large glacier, twice the size of Manhattan, split off on July 16. NBC's Brian Williams reports.
"Arctic sea ice extent this summer is so far tracking at very low, near record levels, and the ice cover is unusually diffuse," Mark Serreze of the National Snow and Ice Data Center told NBC News.
On top of that, he said, the seasonal melt that followed the 2012 winter "started unusually early over most of the Arctic Ocean."
The center's latest report, issued Tuesday, noted that" Arctic sea ice continued to track at levels far below average through the middle of July, with open water in the Kara and Barents seas reaching as far north as typically seen during September."
Thomas Mote, a University of Georgia climatologist who looked at the satellite data, said the melt followed an unusual series of warm air ridges over Greenland since late May, with the strongest coinciding with the rapid thaw in mid-July.
Each successive ridge, Mote told NBC News, was "stronger than the previous one" and it looks like the pattern has finally broken down.
The ridges happened just as a cyclical weather phase known as the North Atlantic Oscillation shifted. "Together, they produced near perfect conditions for this event," Mote added.
Related: Huge Greenland iceberg breaks off glacier
Because they hold so much ice on land, Greenland and Antarctica have the potential to raise sea levels significantly if warming continues or worsens.
Sea levels have already risen by about 8 inches in the last century, partly due to some ice melt but also thermal expansion caused by warming seas.
The U.N. climate panel estimates sea level could rise between 7 inches and nearly two feet this century -- the latter a scenario that could prove catastrophic for many coastal areas around the globe.
NASA said researchers had not yet determined whether this summer's Greenland thaw would be significant enough to raise sea levels.
Greenland has enough ice to raise sea levels by 23 feet if it all melted off.
A recent study found that it could take a long-term increase in global temperatures of just 2-3 degrees Fahrenheit to completely melt Greenland's ice sheet in 2,000 years.
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Satellite pictures were infortunately not available in the 1930's when we experienced severe drought and record temperatures still unmatched by today's heat wave. This country had no where near the industrial development and auto ownership it has today, especially when you factor in China and India. WWII brought tons and tons of airborn pollutants from bombing, oil burning, etc, without an accompaning heat wave during or following the war.
"Ice cores from Greenland's highest region do reveal that such island-wide thaws have happened every 150 years or so, at least over the last few thousand years",
Look out!! The sky is falling!!!!!!!!!!!!!!!
I thought of a way to describe this.
Let's say you decide to paint the walls of your house. You paint 97% of the walls. So 97% of the surface area has some short term wetness to it. But the bulk of the wall, the sheet rock is still solid and is still there. It quickly dries.
That's basically what happened here. Due to cyclical and completely normal and natural conditions warm air was able to move northward over Greenland. It didn't last long. The temperatures were above freezing for just a few hours. Just long enough to melt the surface a little bit. Temperature quickly dropped below freezing again and everything is back to what we call normal.
The slight amount of ice lost to short term melting is comparable to the slight increase in thickness of your wall from a coat of paint. You can't tell the difference.
Here is a a good explanation of what is going on. It also explains why the US is hot but most other areas of the northern hemisphere isn't. Zonal wind patterns switched to Meridional. It lets cold air move south in some areas and lets warm air move north in others.
http://drtimball.com/2012/current-global-weather-patterns-normal-despite-government-and-media-distortions/
for all you naysayers here you go
go to click on any Buoy and look at the sea level trends, don't forget these rises in sea levels are spread over thousands of square miles, for those of you who are not familiar with the metric system 1 inch equals 2.54 cms or 25.4 millimetres, so 6 millimetres is a 1/4 of an inch, not much however that 1/4 of an inch is spread over ten thousand square miles of ocean, do the math!.
I have never seen such a bunch of programmed tbaggers in my life. denial denial denial! Its called global warming and its a fact...satellites have no interest in the results ..they just record it.
So the fact that ice cores show this melting every 150 years for millennia is global warming?
Read more: http://www.foxnews.com/scitech/2012/07/26/skeptics-put-freeze-on-nasa-hot-air-about-greenland-ice/#ixzz21pydursG
The 150-year cycle, even if it exists, doesn't explain why global temperatures have been above the 20th Century average since about 1980, and why there has been a net loss of Greenland ice every year for over a decade.
HOLY CRAP!!! What will we do in 2,000 years and Greenland's ice sheet has disappeared?
Cry today, bitches, for the ice melts tomorrow. I wish I was around when the bleeding hearts proclaim victory over "climate change" and then Earth is hit by a killer meteor. Alas, this day will never come to pass.... just like this stupid ice-sheet melting hysteria.
You and your family are the crying bitches fool.
ron, what do you expect from some guy living in a van, intelligence?
This makes you realize how utterly foolish and stupid all of the deniers really are. They make me want to puke.
Greenland, Greenland, Now how did this island get the name Greenland? Because when a group of Icelanders went to this Island in 900 AD it was Green. I asked that question in 1957, when at the air base, because it sure was not Green. Did the research, now I know why.
Build a sea wall around the big city's on the oceans, so the sea rise will not get there streets wet, wait a few hundred years for the ice packs to form again, then your ancestors will not be able to go to the beach with out climbing over the sea wall. Give me a break, stop griping about things that you will do nothing about. No more coal or oil and see how the world gets on, O Boy back to the 11th. century. That should make all the tree hugger's happy.
TWO VERY IMPORTANT FACTS WHICH EVERYONE NEEDS TO BE AWARE OF!
Once global temperatures rise an average of 2.5 degrees C, all carbon sinks on our planet (on both land and sea) will turn into carbon sources instead.
also .....
N2O is now the number one ozone depletion gas on our planet, and oceanic dead zones can produce as much as 10,000 times the amount of N2O as healthy oceans. (Dead forests produce a large amount of N2O, too. N2O has about 310 times the global warming potential of CO2) This erosion of our ozone layer in turn allows more UV light to strike the face of the Earth, which in turn attacks plants and organisms which turn CO2 back into O2.
I sincerely hope everyone perceives the impending threat here BEFORE it is too late for our world. Otherwise we are all eventually goners. - RC
(When N2O finds its way up into the stratosphere, solar radiation converts it to nitrogen oxides (NO & NO2), and it is these nitrogen oxides which then attack the ozone layer in much the same way that chlorine does from CFCs.) - RC
Iam affraid
Meanwhile, the head of the conservative Koch-funded Berkley team, Richard Mueller, just published an op-ed in the New York Times that he is now a "converted skeptic". After his team of skeptical scientists re-analyzed all the temperature data they could get, they now assert the IPCC underestimated the rate our planet is heating, and mankind is causing almost all of it.