NASA data show Arctic saw fastest August sea ice retreat on record
September 28, 2008
The graph shows the daily retreat of sea ice during 2008 compared to the long-term average and the 2007 record low. Credit: Robert Simmon/Jesse Allen/Michon Scott/NSIDC
Following a record-breaking season of arctic sea ice decline in 2007, NASA scientists have kept a close watch on the 2008 melt season. Although the melt season did not break the record for ice loss, NASA data are showing that for a four-week period in August 2008, sea ice melted faster during that period than ever before.
Each year at the end of summer, sea ice in the Arctic melts to reach its annual minimum. Ice that remains, or "perennial ice," has survived from year to year and contains old, thick ice. The area of arctic sea ice, including perennial and seasonal ice, has taken a hit in past years as melt has accelerated. Researchers believe that if the rate of decline continues, all arctic sea ice could be gone within the century.
"I was not expecting that ice cover at the end of summer this year would be as bad as 2007 because winter ice cover was almost normal," said Joey Comiso of NASA's Goddard Space Flight Center in Greenbelt, Md. "We saw a lot of cooling in the Arctic that we believe was associated with La Niña. Sea ice in Canada had recovered and even expanded in the Bering Sea and Baffin Bay. Overall, sea ice recovered to almost average levels. That was a good sign that this year might not be as bad as last year."
The 2008 sea ice minimum was second to 2007 for the record-lowest extent of sea ice, according to a joint announcement Sept. 16 by NASA and the University of Colorado's National Snow and Ice Data Center (NSIDC) in Boulder, Colo. As of Sept. 12, 2008, the ice extent was 1.74 million square miles. That's 0.86 million square miles below the average minimum extent recorded from 1979 to 2000, according to NSIDC.
Contributing to the near-record sea ice minimum in 2008 was a month-long period in the summer that saw the fastest-ever rate of seasonal retreat during that period. From August 1 to August 31, NASA data show that arctic sea ice extent declined at a rate of 32,700 square miles per day, compared to a rate of about 24,400 square miles per day in August 2007. Since measurements began, the arctic sea ice extent has declined at an average rate of 19,700 miles per day at the point when the extent reaches its annual minimum.
Observations of changes to sea ice over time are possible due to a 30-year record of data from NASA and other agency satellites, including Nimbus-7, Aqua, Terra and the Ice, Cloud, and land Elevation Satellite (ICESat).
Researchers say that the recent seasonal acceleration could be in part due to conditioning going on in the Arctic. For example, research by Jennifer Kay of the National Center for Atmospheric Research in Boulder, Colo., and colleagues reported this April in Geophysical Research Letters that reduced cloud cover in 2007 allowed more sunlight to reach Earth, contributing to a measureable amount of sea ice melt at the surface. Reduced cloud cover also contributed to warmer ocean surface temperatures that led to melting of the ice from below.
"Based on what we've learned over the last 30 years, we know that the perennial ice cover is now in trouble," Comiso said. "You need more than just one winter of cooling for the ice to recover to the average extent observed since the measurements began. But the trend is going the other way. A warming Arctic causes the surface water to get warmer, which delays the onset of freeze up in the winter and leads to a shorter period of ice growth. Without the chance to thicken, sea ice becomes thinner and more vulnerable to continued melt."
Source: NASA's Goddard Space Flight Center
-
Study shows global glaciers, ice caps, shedding billions of tons of mass annually
Feb 08, 2012 |
4.4 / 5 (8) |
9
-
In scientific coup, Russians reach Antarctic lake
Feb 08, 2012 |
4.8 / 5 (6) |
6
-
New study shows correlation between summer Arctic sea ice cover and winter weather in Central Europe
Feb 01, 2012 |
4.8 / 5 (5) |
0
-
What do killer whales eat in the Arctic?
Jan 30, 2012 |
4 / 5 (1) |
0
-
New study may answer questions about enigmatic Little Ice Age
Jan 30, 2012 |
4.7 / 5 (7) |
9
-
Engineers build first sub-10-nm carbon nanotube transistor
Feb 01, 2012 |
4.9 / 5 (31) |
30
-
Something old, something new: Evolution and the structural divergence of duplicate genes
Jan 31, 2012 |
4.6 / 5 (7) |
1
-
The hidden nanoworld of ice crystals: Revealing the dynamic behavior of quasi-liquid layers
Jan 30, 2012 |
5 / 5 (3) |
1
-
Stock market network reveals investor clustering
Jan 27, 2012 |
3.9 / 5 (23) |
8
-
Of microchemistry and molecules: Electronic microfluidic device synthesizes biocompatible probes
Jan 26, 2012 |
5 / 5 (1) |
0
-
Discrepancy between oxygen and carbon-dioxide levels
Feb 09, 2012
-
where gems are found in the world
Feb 09, 2012
-
Wind Waves in Reservoir ~ Wind run-up and Wind set-up
Feb 08, 2012
-
Balance of oxygen in the atmosphere
Feb 01, 2012
-
The case for a methanol-based economy
Jan 30, 2012
-
Weather in a rotating cylinder
Jan 25, 2012
- More from Physics Forums - Earth
More news stories
Humans may have helped the decline of African rainforests 3000 years ago
(PhysOrg.com) -- Large areas of rainforests in Central Africa mysteriously disappeared over three thousand years ago, to be replaced by savannas. The prevailing theory has been that the cause was a change ...
Could Venus be shifting gear?
(PhysOrg.com) -- ESAs Venus Express spacecraft has discovered that our cloud-covered neighbour spins a little slower than previously measured. Peering through the dense atmosphere in the infrared, the ...
Space & Earth / Space Exploration
20 hours ago |
5 / 5 (7) |
8
|
NASA budget will axe Mars deal with Europe: scientists
US President Barack Obama's budget proposal to be submitted next week for 2013 will cut NASA's budget by 20 percent and eliminate a major partnership with Europe on Mars exploration, scientists said Thursday.
Space & Earth / Space Exploration
23 hours ago |
5 / 5 (2) |
20
Mars Science Laboratory computer issue resolved
(PhysOrg.com) -- Engineers have found the root cause of a computer reset that occurred two months ago on NASA's Mars Science Laboratory and have determined how to correct it.
Space & Earth / Space Exploration
21 hours ago |
4.7 / 5 (6) |
4
|
Two new moons for Jupiter
Advances in technology have lead to the discovery of new planets outside of our Solar System, and now even new moons in our own backyard.
Space & Earth / Space Exploration
20 hours ago |
4 / 5 (1) |
7
Anonymous knocks CIA website offline (Update)
The website of the Central Intelligence Agency was inaccessible on Friday after the hacker group Anonymous claimed to have knocked it offline.
New error-correcting codes guarantee the fastest possible rate of data transmission
Error-correcting codes are one of the triumphs of the digital age. Theyre a way of encoding information so that it can be transmitted across a communication channel such as an optical fiber o ...
Small modular reactor design could be a 'SUPERSTAR'
(PhysOrg.com) -- Though most of today's nuclear reactors are cooled by water, we've long known that there are alternatives; in fact, the world's first nuclear-powered electricity in 1951 came from a reactor ...
New power source discovered
(PhysOrg.com) -- Researchers at the Massachusetts Institute of Technology (MIT) and RMIT University have made a breakthrough in energy storage and power generation.
The power of estrogen -- male snakes attract other males
A new study has shown that boosting the estrogen levels of male garter snakes causes them to secrete the same pheromones that females use to attract suitors, and turned the males into just about the sexiest ...
Google users warned of threat to smartphone wallets
Users of Google smartphone wallets were being warned on Friday that there is a way to crack pass codes intended to thwart thieves from going on illicit shopping sprees.
Sep 28, 2008
Rank: 3 / 5 (8)
Sep 28, 2008
Rank: 3.1 / 5 (7)
I am shocked (SHOCKED!!!) to discover that the max melting rate this year exceeded that of any other year in our extensive 30-year data set.
I mean, really, it is utterly, totally, and without question inconceivable that our data - which, after all, covers approximately 0.000000667% of the Earth's 4.5 billion-year existence - doesn't indicate the set of all possible "normal" melting rates, so anything outside our baseline data must be extraordinary and cause for immediate concern.
This article is sloppy tripe, at best.
1. Assuming a human life-span of 100 years, 30 years of Earth's existence is the equivalent of roughly 21.04 seconds of a human's life. (For that matter, the 12000 years since the beginning of the Neolithic translate to around 2 hours and 20 minutes of a human lifetime).
2. The pretty picture and its associated graph look nice, but are uninformative at best and misleading at worst. The map shows the "long-term" (1979-2000) median minimum ice sheet (why stop in 2000? Why not 1999 or 2006 or 1985?), but tells us nothing about the variance, prior minimum and maximum, standard deviation, or even the mean. If I sample the net worth of 30 households in my neighborhood, where 20 are young, 1st-time homeowners and 10 are retired empty-nesters with no debt, what value does the median net worth have? Can it really tell you something useful about my neighborhood, let alone the entire state, country, or world? And how does charting the "average" (mean? median? mode?) daily sea ice retreat against 2 apparent outliers tell us anything useful without the afformentioned variance, standard deviation, etc? Of course, it doesn't.
3. With all we know about the geologic history of our planet, how we can possibly proceed with "science" that presumes a static environment is beyond my comprehension. Western society has developed an unfortunate and sickening arrogance regarding mankind's impact on the Earth. Basically, there is an implicit assumption that "natural" changes (a la evolution) ceased with the advent of "scientific man", and that all subsequent changes to our suddenly static planet were the result of man's "interference" with nature (as if we aren't PART of nature). This manifests itself everywhere from the dogma of climate change, to the introductory movie at Volcano National Park on Hawaii, where the narrator describes the "pristine" environment created when Polynesian explorers brought their domestic animals to the islands, as compared to the invasive and destructive results of Western explorers arriving in the 19th century. Strip away everything else, and you have two separate instances of the same event: human explorers introduce alien species into an isolated ecosystem. To paraphrase Hamlet, the only thing that makes either event "good" or "bad" is our perception. I'm not saying that man doesn't impact the world in ways large and small, but I am saying that we have a tendency to over-estimate our own importance.
And no, I'm sure none of this has to do with employing alarmist rhetoric to scare up research sponsors and grant money. That can't be why climate change has seen what is possibly the fastest formation of a "scientific consensus" ever for a question this complicated.
Please, try to think for yourselves just a little bit. It won't hurt much, I promise.
Sep 28, 2008
Rank: 3.5 / 5 (6)
Sep 28, 2008
Rank: 1.7 / 5 (3)