Satellites see unprecedented Greenland ice sheet surface melt

Jul 24, 2012
Extent of surface melt over Greenland’s ice sheet on July 8 (left) and July 12 (right). Measurements from three satellites showed that on July 8, about 40 percent of the ice sheet had undergone thawing at or near the surface. In just a few days, the melting had dramatically accelerated and an estimated 97 percent of the ice sheet surface had thawed by July 12. In the image, the areas classified as “probable melt” (light pink) correspond to those sites where at least one satellite detected surface melting. The areas classified as “melt” (dark pink) correspond to sites where two or three satellites detected surface melting. The satellites are measuring different physical properties at different scales and are passing over Greenland at different times. As a whole, they provide a picture of an extreme melt event about which scientists are very confident. Credit: Credit: Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory

For several days this month, Greenland's surface ice cover melted over a larger area than at any time in more than 30 years of satellite observations. Nearly the entire ice cover of Greenland, from its thin, low-lying coastal edges to its 2-mile-thick center, experienced some degree of melting at its surface, according to measurements from three independent satellites analyzed by NASA and university scientists.

On average in the summer, about half of the surface of Greenland's ice sheet naturally melts. At high elevations, most of that melt water quickly refreezes in place. Near the coast, some of the melt water is retained by the ice sheet and the rest is lost to the ocean. But this year the extent of ice melting at or near the surface jumped dramatically. According to satellite data, an estimated 97 percent of the ice sheet surface thawed at some point in mid-July.

Researchers have not yet determined whether this extensive melt event will affect the overall volume of ice loss this summer and contribute to .

"The is a vast area with a varied history of change. This event, combined with other natural but uncommon phenomena, such as the large calving event last week on , are part of a complex story," said Tom Wagner, NASA's program manager in Washington. " are helping us understand how events like these may relate to one another as well as to the broader ."

Son Nghiem of NASA's Jet Propulsion Laboratory in Pasadena, Calif., was analyzing from the 's (ISRO) Oceansat-2 satellite last week when he noticed that most of Greenland appeared to have undergone surface melting on July 12. Nghiem said, "This was so extraordinary that at first I questioned the result: was this real or was it due to a data error?"

Nghiem consulted with Dorothy Hall at NASA's Goddard Space Flight Center in Greenbelt, Md. Hall studies the surface temperature of Greenland using the Moderate-resolution Imaging Spectroradiometer (MODIS) on NASA's Terra and Aqua satellites. She confirmed that MODIS showed unusually high temperatures and that melt was extensive over the ice sheet surface.

Thomas Mote, a climatologist at the University of Georgia, Athens, Ga., and Marco Tedesco of City University of New York also confirmed the melt seen by Oceansat-2 and MODIS with passive-microwave satellite data from the Special Sensor Microwave Imager/Sounder on a U.S. Air Force meteorological satellite.

The melting spread quickly. Melt maps derived from the three satellites showed that on July 8, about 40 percent of the ice sheet's had melted. By July 12, 97 percent had melted.

This extreme melt event coincided with an unusually strong ridge of warm air, or a heat dome, over Greenland. The ridge was one of a series that has dominated Greenland's weather since the end of May. "Each successive ridge has been stronger than the previous one," said Mote. This latest heat dome started to move over Greenland on July 8, and then parked itself over the ice sheet about three days later. By July 16, it had begun to dissipate.

Even the area around Summit Station in central Greenland, which at 2 miles above sea level is near the highest point of the ice sheet, showed signs of melting. Such pronounced melting at Summit and across the has not occurred since 1889, according to ice cores analyzed by Kaitlin Keegan at Dartmouth College in Hanover, N.H. A National Oceanic and Atmospheric Administration weather station at Summit confirmed air temperatures hovered above or within a degree of freezing for several hours July 11-12.

"Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time," says Lora Koenig, a Goddard glaciologist and a member of the research team analyzing the satellite data. "But if we continue to observe melting events like this in upcoming years, it will be worrisome."

Nghiem's finding while analyzing Oceansat-2 data was the kind of benefit that NASA and ISRO had hoped to stimulate when they signed an agreement in March 2012 to cooperate on Oceansat-2 by sharing data.

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User comments : 30

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Vendicar_Decarian
3.3 / 5 (19) Jul 24, 2012
Where are the denialists? They should be here whining about how the ice in Greenland can't be melting because they just purchased some bags of ice from their local 7:11 and the price hasn't changed, and according to the law of supply and demand if there is less ice then there should be a higher price.

Particularly true on such a Cold American Summer as this one.

Proven colder by the low temperatures in the 7:11's ice box.

rubberman
2.5 / 5 (21) Jul 24, 2012
Perhaps a mass collection and delivery of said meltwater to the US heartland could help ease the strain from the drought that has nothing to do with climate change and will certainly end soon...or is someone just going to claim there is no drought, and therefore stop the drought.
Parkertard will be along when he is done having coffee with Estevan.
JustAnyone
3 / 5 (17) Jul 24, 2012
In science, two people arguing doesn't mean the strength of their arguments is equal. The media giving equal time to denialists gives them equal credibility in the listener's view. There IS such a thing as objective truth (defined by scientific trial/error/experiment/peer review/replication).
A2G
3.1 / 5 (17) Jul 24, 2012
"Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time," says Lora Koenig, a Goddard glaciologist and a member of the research team analyzing the satellite data. "But IF we continue to observe melting events like this in upcoming years, it will be worrisome."

The expert is quoted as saying this melting was not unusual, and in fact was expected and right on time. That is what the "expert" said.

So what is the issue?
rubberman
2.7 / 5 (19) Jul 24, 2012
In Science, if all observed evidence supports a theory that has a strong basis routed in proven physics and said evidence continues to mount on a daily basis, a satisfactory amount of valid, competing evidence must be provided if the theory is to be tested and/or disproven. Denialists can have 100% of opinion based media to themselves, it will never make them correct because they will still have 0% of fact based publication.
rubberman
2.7 / 5 (19) Jul 24, 2012
"So what is the issue?"

Well, let's start with a global temperature increase of almost 1 degree celcius since the last 150 year melt occurred, add 100 additional PPM of CO2 which may or may not be responsible for the warming but I sincerly hope that it is because if natural variability is responsible then we haven't seen what the extra CO2 is going to do YET. I guess the jury is out until the next time the satelite imagary looks like the above..... Hopefully not for another 150 years, but I'll bet we see it again within the next 5.
Vendicar_Decarian
3.2 / 5 (11) Jul 24, 2012
There is no drought in America because Greenland is producing plenty of melt-water. This drought business must obviously be a Liberal/Democrat/Communist conspiracy to destroy the perfection o Free Market Capitalism.

"delivery of said meltwater to the US heartland" - Rubberman
Caliban
2.2 / 5 (10) Jul 24, 2012
"Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time," says Lora Koenig, a Goddard glaciologist and a member of the research team analyzing the satellite data. "But IF we continue to observe melting events like this in upcoming years, it will be worrisome."

The expert is quoted as saying this melting was not unusual, and in fact was expected and right on time. That is what the "expert" said.

So what is the issue?


The issue is: what is your point?

NotParker
2 / 5 (22) Jul 24, 2012
Where are the denialists?


We were reading to the bottom of the article:

"Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time,""
Lurker2358
2.9 / 5 (21) Jul 24, 2012
We were reading to the bottom of the article:

"Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time,""


Ahah!

So you admit you're a denialist, not a skeptic!
Pkunk_
2.1 / 5 (14) Jul 25, 2012
We were reading to the bottom of the article:

"Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time,""


Ahah!

So you admit you're a denialist, not a skeptic!


And you are a warmist.
Birger
3.7 / 5 (6) Jul 25, 2012
In theory you could build a 4000 km pipeline to bring meltwater into the "dustbowl" but I suspect a desalination plant would be cheaper.

You could also put a 4000 km pipeline on the bottom of the sea and connect Australia to the Antarctic meltwater, but the $$$$ would be horrific.

Melting occurs for various reasons, and in various regions. The situation at Greenland should be taken in context with other anomalies, and when you filter away melting that may be recurrent events you still get a scary picture.
Egleton
1 / 5 (9) Jul 25, 2012
If this crazy weather keeps up some people are going to miss their breakfast.
Gail Tyverberg (Gail the Actuary) has to make risk assessments for the insurance companies. Perhaps we should ask her whether she thinks the insurance companies are paying out more these days.
http://ourfiniteworld.com/
R2Bacca
3.2 / 5 (6) Jul 25, 2012
The issue is: what is your point?


I believe that the point is that if you are expecting something to happen, and it does happen "right on time", then using the word "Unprecedented" in the title is misleading.

http://www.merria...cedented
Lurker2358
2 / 5 (8) Jul 25, 2012
The issue is: what is your point?


I believe that the point is that if you are expecting something to happen, and it does happen "right on time", then using the word "Unprecedented" in the title is misleading.

http://www.merria...cedented


Technically, this is about 30 years ahead of time if the long term average was once every 150 years, and that assumes it's the same cycle.

Suppose this is AGW, and the 150 year cycle is still 30 years away from repeating...

===

I used to believe this was all rebound from the Year without a Summer, but the fact is the melt rate in many regions of the world is worse than the historical records from BEFORE that event, proving the rebound it cannot be the primary driver in warming.

I've never worked with ice core samples, but I assume there is an enormous marker layer for that event, which I suppose must include large volcanic dust particles with very thick ice and smaller and smaller particles above it.
Lurker2358
1.7 / 5 (6) Jul 25, 2012
But that assumes that layer has survived the melting since then, which it probably has not survived in some regions, seeing as how the rate of melting and calving has become so high.

At any rate, the Year without a Summer should have screwed up the timing or intensity of other natural cycles for many years after the initial event, and this probably happened immediately after Krakatoa as well. After all, a large volcano blocks out the Sun initially for several years in some cases, but it also dumps a large amount of CO2 into the atmosphere (relative to humanity at that time for Tambora and Krakatoa).

There seems to be a relationship between the eruption of Thera at Santorini and the biblical Plagues in Egypt, as several of them can be explained as a natural consequence of a combination of blocking out the Sun as well as acid rains, etc, Livestock, infants and elderly inhaling dust. What it doesn't explain is the selective nature of the plague killing only Egyptians and their livestock
Lurker2358
2.1 / 5 (7) Jul 25, 2012
For example, they state that the previous melting of this sort occurred in 1889, well that is 6 year after Krakatoa, which is enough time for the dust and aerosols to leave the atmosphere, but the excess CO2 bomb it created would remain in the atmosphere forever, and would be a warming agent. Thus after the aerosols and dust settled, the warming could have a rapid spike and melt the ice due to CO2.

Just like the Tambora incident, there should be volcanic dust sorted by grain size: Largest grains on the bottom, with a thick layer of ice on top for several years with finer and finer dust inclusions. Finally, there should be a discontinuity above this layer caused by the spike and rebound melting that followed when the air cleared.

And so, the "150 year event" that happened in 1889 is probably not even a "cycle" at all, but is more likely related to the "loudest sound ever heard" i.e. Krakatoa's eruption.
Torbjorn_Larsson_OM
3.7 / 5 (3) Jul 25, 2012
@ A2G:

The issue is the AGW regime that the climate is in, and how we observe that the GW rise have made a 50/50 hot/cold ratio of climate extreme events go to a 70/30, testing the theory. So we wonder if this will fir the trend. If so, it will be repeated well before 150 years.

@ Pkunk:

There is nothing like a "warmist". An acceptance of climate science, perhaps. But no one thinks "warming causes AGW", but that AG warming is precisely caused by greenhouse gas emissions.

@ R2Bacca:

Presumably the title was referring to the satellite observations and their note of speed, which is unprecedented. The ice cores will only tell you extent of melting during a year (summer), nit give a resolution of days.
Howhot
2.5 / 5 (8) Jul 27, 2012
I have come to the conclusion AGW is far worst than we think. Worst than the worst case scenarios, I predict it happens again next year.
Lurker2358
1.5 / 5 (8) Jul 28, 2012
I have come to the conclusion AGW is far worst than we think. Worst than the worst case scenarios, I predict it happens again next year.


Stick around.

2018 and 2023 should be quite telling.

I also expect next year to be slightly hotter than this year, and then 2014 will be about the same as this year.
NotParker
1.9 / 5 (14) Jul 28, 2012
I have come to the conclusion AGW is far worst than we think. Worst than the worst case scenarios, I predict it happens again next year.


2011 was the 11th warmest year according to NOAA (which in the real world would make it average).

Jan-Jun 2011 is about the same temperature as Jan-Jun 2012 putting 2012 on track for being not that warm.
RobPaulG
1.7 / 5 (11) Jul 29, 2012
Ice melting during a hot summer. The horror, the horror...
Vendicar_Decarian
3.7 / 5 (6) Jul 29, 2012
Careful. Weather is fickle.

"I predict it happens again next year." - HowHot
djr
5 / 5 (4) Jul 29, 2012
2011 was the 11th warmest year according to NOAA (which in the real world would make it average). Define average please..

I am glad that we are willing to recognize NOAA as a valid source for climate data - rather than accuse them of being climate liars. To get the full understanding of NOAA's appraisal of the current climate - one only needs to go to the 2011 climate report - http://www.ncdc.n...2011.php

Just a quick quote from the report - to show that picking one year - 2011 and trying to make generalizations about the climate from that year - is pure rubbish. "La Niña conditions in the tropical Pacific Ocean throughout much of 2011 contributed to an overall cooler year than 2010, which ranked as either warmest or second warmest year on record" There is a very instructive graph in the report - entitled "yearly global surface temperature anomalies" http://www.climat...perature
djr
4.3 / 5 (6) Jul 29, 2012
"Careful. Weather is fickle." - Smile - so is Richard Muller - he is now a true believer Vendi (well almost) - and with money from the Koch brothers to boot - http://www.newser...ame.html
Waaalt
1 / 5 (8) Jul 29, 2012
If it's global warming, why now and not last year?

This is almost definitely because of the huge wildfires in Siberia this summer.

I made a larger post with some links for sources, but that post hasn't been approved yet.

Anyways, anybody can look up how soot influences melt rate but it's not a controversial idea at all. It's well established and anyone can look it up.
NotParker
1.7 / 5 (12) Jul 29, 2012
"Careful. Weather is fickle." - Smile - so is Richard Muller - he is now a true believer Vendi (well almost) - and with money from the Koch brothers to boot - http://www.newser...ame.html


Trumped by real science at WUWT.

http://wattsupwit...lease-2/

*By the way, Muller claims a 1.5F rise from "50 years ago." In the USA the rise is half of that from the 1930s.

Muller cherry-picked the cold early 1960s as a starting point for his scare story bit of propaganda.
NotParker
1.7 / 5 (12) Jul 29, 2012

I am glad that we are willing to recognize NOAA as a valid source for climate data


Demolished by WUWT. NOAA exagerates.

"The new improved assessment, for the years 1979 to 2008, yields a trend of 0.155C per decade from the high quality sites, a 0.248 C per decade trend for poorly sited locations, and a trend of 0.309 C per decade after NOAA adjusts the data. "

NOAA essentially doubles the trend. And Muller doubles the already doubled NOAA trend.
I just use them to demolish propagandists like Muller at BEST.
djr
3.9 / 5 (7) Jul 29, 2012
"Demolished by WUWT. NOAA exagerates" So you will quote them when it serves your agenda - and disparage them when there data does not. I would say that is a classic case of confirmation bias.

so Watts writes a paper that contradicts himself - "the Leroy 1999 site rating method employed to create the early metadata, and employed in the Fall et al 2011 paper I co-authored was incomplete, and didnt properly quantify the effects." He now recognizes his error - and in a non peer reviewed paper - begs forgiveness. By the way - wouldn't a .155C per decade trend be pretty much in line with the scientific consensus regarding warming in the past 100 years?
NotParker
1.5 / 5 (8) Jul 30, 2012
"Demolished by WUWT. NOAA exagerates" So you will quote them when it serves your agenda - and disparage them when there data does not. I would say that is a classic case of confirmation bias.

so Watts writes a paper that contradicts himself - "the Leroy 1999 site rating method employed to create the early metadata, and employed in the Fall et al 2011 paper I co-authored was incomplete, and didnt properly quantify the effects." He now recognizes his error - and in a non peer reviewed paper - begs forgiveness. By the way - wouldn't a .155C per decade trend be pretty much in line with the scientific consensus regarding warming in the past 100 years?


The .155C / decade is from all Class 1 and 2 stations including airports.

When you use Class 1 and Class 2 rural stations which are less affected by UHI, Watts paper shows:

0.032 C per decade

There is no warming.