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Greenland Ice Sheet Melt Nearing Critical ‘Tipping Point’

The Greenland ice sheet is poised for another record melt this year, and is approaching a "tipping point" into a new and more dangerous melt regime in which the summer melt area covers the entire land mass, according to new findings from polar researchers. 

The ice sheet is the focus of scientific research because its fate has huge implications for global sea levels, which are already rising as ice sheets melt and the ocean warms, exposing coastal locations to greater damage from storm surge-related flooding.

Trend in the reflectivity of high elevation ice in Greenland, showing the record low as of June 26, 2012. Note: the vertical axis should be labeled "unitless" rather than as a percentage. Credit: Jason Box/Byrd Polar Research Center Wiki.

Greenland's ice has been melting faster than many scientists expected just a decade ago, spurred by warming sea and land temperatures, changing weather patterns, and other factors. Until now, though, most of the focus has been on ice sheet dynamics — how quickly Greenland's glaciers are flowing into the sea. But the new research raises a different basis for concern.

The new findings show that the reflectivity of the Greenland ice sheet, particularly the high-elevation areas where snow typically accumulates year-round, have reached a record low since records began in 2000. This indicates that the ice sheet is absorbing more energy than normal, potentially leading to another record melt year — just two years after the 2010 record melt season.

“In this condition, the ice sheet will continue to absorb more solar energy in a self-reinforcing feedback loop that amplifies the effect of warming,” wrote Ohio State polar researcher Jason Box on the blog. Greenland is the world's largest island, and it holds 680,000 cubic miles of ice. If all of this ice were to melt — which, luckily won't happen anytime soon — the oceans would rise by more than 20 feet.

In a new study, Box and a team of researchers describe the decline in ice sheet reflectivity and the reasons behind it, noting that if current trends continue, the area of ice that melts during the summer season is likely to expand to cover all of Greenland for the first time in the observational record, rather than just the lower elevations at the edges of the continent, as is the case today. The study has been accept for publication in the open access journal The Cryosphere.

Satellite data of Greenland reflectivity June 1-22, 2012 versus the same periods in previous Junes back to 2000. The blue colors indicate a decrease in reflectivity compared to previous Junes. Credit: NASA/

The high reflectivity of snow is what has kept Greenland so cold by redirecting incoming heat from the sun back out toward space. But with several factors combining to increase temperatures in Greenland and reduce the reflectivity of the snow and ice cover, the ice sheet is becoming less efficient at reflecting that heat energy, and as a consequence melt seasons are becoming more severe.

Freshly fallen snow reflects up to 84 percent of incoming sunlight, but during the warm season the reflectivity declines as the ice grains within the snowpack change shape and size. In addition, once snow cover melts completely it often reveals underlying ice that has been darkened by dust and other particles, whose surface absorbs more solar energy, promoting heating.

Box's research has shown that the change in the reflectivity of the Greenland ice sheet during the 12 summers between 2000 and 2011 allowed the ice sheet to absorb an extra 172 "quintillion joules" of energy, nearly twice the amount of energy consumed in the U.S. in 2009. This extra energy has gone into raising the temperature of the snow and ice cover during summer.

“If the area of the Greenland Ice Sheet experiencing net melt expands to eclipse the accumulation zone of the ice sheet, the ice sheet will, by definition, be tipped into a state of inevitable decline,” said William Colgan, a research associate at the Cooperative Institute for Research in Environmental Sciences (CIRES) who did not participate in the new research. 

In an interview shortly before leaving for a Greenland research expedition, Box said the new findings reveal that the normally snowy, windswept higher-elevation areas of Greenland are rapidly transitioning to melt during the summer in a similar manner to the lower reaches of the ice sheet.

“It appears that we’re about to cross a threshold in summer . . . you might even call it a tipping point as we go into a net energy absorption” of the higher elevations, Box said. “Then we’ll see the melt area expanding abruptly and potentially covering the entire ice sheet in summer for the first time in observations.”

Box said the shift may take another decade or so, provided that current trends continue. “We’re right on the threshold.”

Colgan said it’s difficult to make predictions based on the reflectivity record, but it would be significant if 2012 becomes another record melt year.

“The frequency with which Greenland record melt years are being established is exceptional, and certainly supports the notion that the Arctic climate is warming, and moving away from an equilibrium climate state in which extreme or record events are relatively rare,” Colgan said in an email conversation.


By Aaron Lewis (Pleasant Hill/CA/94523)
on June 29th, 2012

As sea ice around Greenland declines, latent heat in the atmosphere is more likely to reach the GIS.
There is a lot of heat in the oceans and a lot of area to collect more heat, so this can be a huge source of heat.

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By Jewel Rainbow (Queensland Australia)
on June 29th, 2012

Alarming - yet will it be enough to convince the world’s leading polluters to URGENTLY clean up their air pollution. China, India, the US and Indonesia could really make a difference if there is the political will and international co-operation to avoid the imminent critical tipping-point.

Reply to this comment

By richard schumacher
on June 30th, 2012

The ice cap doesn’t have to melt to raise sea level: if it were to slide off Greenland into the sea, that would raise sea level immediately.  The summer melt could lubricate the base of the ice cap and increase the rate of flow of glaciers into the sea, and so raise sea level far faster than would be implied by the increased heating alone.  Once floating in the sea the resulting icebergs could take their sweet time melting; the damage would already have been done.

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By Andy
on June 30th, 2012

The models were far too optomistic.  The loss of reflectivity, methane plumes, melting permafrost, and the stubborn refusal of humans to reduce emmissions, and in fact continue to increase the amount of emmissions every day.  We are actually stuffed.  The only concievable way to save the current climate is by carbon capture, on a global scale starting today.  Which isn’t going to happen, especially when the majority of the population believes that climate change is a scam run by some non profit organisations for devious purposes.  What a joke.

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By Kevin Birdwell (Knoxville TN 37931)
on June 30th, 2012

No doubt melting will continue.  However, it should be noted the the Greenland Ice Sheet mostly survived the Eemian Period (125k years ago) when global temperatures were more than 2C above present and hippos lived in Southern England.

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By spangled drongo (australia)
on July 1st, 2012

Your graph is a shocking misrepresentation of the original. blog.

Reply to this comment

on July 2nd, 2012

“By Jewel Rainbow (Queensland Australia)
on June 29th, 2012
Alarming - yet will it be enough to convince the world’s leading polluters to URGENTLY clean up their air pollution. China, India, the US and Indonesia could really make a difference if there is the political will and international co-operation to avoid the imminent critical tipping-point.”

how long will it take for each one of us to change our behavior to one that consumes little. lives simply and is austere? change begins with each one of is. that is what it means to grow up and be an ethical, responsible, conscious adult.. lets please stop blaming it on ‘them’ and each one of us go look in the mirror.

is conservation and frugality fun? some parts are (like needing to earn less money) and some parts aren’t… but if we are to survive, we each need to walk the talk.


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on July 3rd, 2012

@ spangled drongo

No it isn’t. But the source has not been given correctly. See here:

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By Bill Lasley (Santa Monica, California)
on July 4th, 2012

People don’t want to believe in climate change, they’d rather believe that God will protect them, so nothing is going to change fast enough to stop catastrophic sea level rise. The best people can do is sell off their beach front properties while they’re still valuable.

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By Jay Carlisle (Warrenton, OR 97146)
on July 24th, 2012

Spooky spot on…


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By news (Kansas)
on January 25th, 2013

Saw this article linked on  

Highly interesting

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By jim adams (louisa/VA/23093)
on July 30th, 2013

I keep coming back to “how to boil a frog”, and the answer is to increase the temperature very, very slowly which is what we humans have been doing to our planet for the last 8000 years. Then, a bit more rapidly since the industrial revolution.  In the last three decades, the CO2 has been going up rapidly, except a large amount was taking out by the oceans in a way which turned our oceans into a carbonic acid bath. Even the news that CO2 had reach 400 ppm—-???

Still no frog reaction.

Check out: and click on the “permafrost’ subheading.  It says we have 8 years IF we start acting at full speed—now.  So hope for a hot, hot, hot summer this and next year. Something which will get our froggy attention.  I don’t think anything else will.

Oceans acid and oysters can’t set shells—placidly treading water…..
Greenland and Antarctica melting at record speeds—placidly treading water…...
Warmer oceans increase water vapor in the atmosphere and storms are increasingly powerful—placidly treading water…...

We seem to have a belief of the robustness of the United States to withstand whatever is thrown against us.And it just ain’t so. Most recently, the Republicans played a game of fiscal brinkmanship with the US economy. They spent down the Clinton surplus and spent up the Bush deficit so that when the 2008 meltdown occurred, the whole world economy teetered. We in the US are on the verge of bankruptcy—which for the sake of this discussion means we have no money do the necessary large projects for planetary survival.

Additionally, our infrastructure is particularly vulnerable to temperatures above 120 degrees F: railroads kink (, highways buckle or melt, bridges collapse, above ground pipelines break and gush, electrical lines carry significantly less current. If some of these happen, we might quit beeing so froggy.

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