Study explains early warming of West Antarctica at end of last ice age
CORVALLIS, Ore. – West Antarctica began emerging from the last ice age about 22,000 years ago – well before other regions of Antarctica and the rest of the world, according to a team of scientists who analyzed a two-mile-long ice core, one of the deepest ever drilled in Antarctica.
Scientists say that changes in the amount of solar energy triggered the warming of West Antarctica and the subsequent release of carbon dioxide (CO2) from the Southern Ocean amplified the effect and resulted in warming on a global scale, eventually ending the ice age.
Results of the study were published this week in the journal Nature. The authors are all members of the West Antarctic Ice Sheet Divide project, which was funded by the National Science Foundation.
The study is significant because it adds to the growing body of scientific understanding about how the Earth emerges from an ice age. Edward Brook, an Oregon State University paleoclimatologist and co-author on the Nature study, said the key to this new discovery about West Antarctica resulted from analysis of the 3,405-meter ice core.
“This ice core is special because it came from a place in West Antarctica where the snowfall is very high and left an average of 20 inches of ice or more per year to study,” said Brook, a professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “Not only did it allow us to provide more accurate dating because we can count the layers, it gave us a ton more data – and those data clearly show an earlier warming of the region than was previously thought.”
Previous studies have pointed to changes in the Earth’s orbit around the sun as the initial trigger in deglaciation during the last ice age. An increase in the intensity of summer sunlight in the northern hemisphere melted ice sheets in Canada and Europe starting at about 20,000 years ago and is believed to have triggered warming elsewhere on the globe.
It previously was thought that Antarctica started its major warming a few thousand years later, at about 18,000 years before present. However, the new study shows that at least part of Antarctica started to warm 2,000 to 4,000 years before this. The authors hypothesize that changes in the total amount of sunlight in Antarctica and melt-back of sea ice caused early warming at this coastal site – warming that is not recorded by ice cores in the interior of the continent.
“The site of the core is near the coast and it conceivably feels the coastal influence much more so than the inland sites where most of the high-elevation East Antarctic cores have been drilled,” Brook said. “As the sunlight increased, it reduced the amount of sea ice in the Southern Ocean and warmed West Antarctica. The subsequent rise of CO2 then escalated the process on a global scale.”
“What is new here is our observation that West Antarctica did not wait for a cue from the Northern Hemisphere before it began warming,” Brook said, “What hasn’t changed is that the initial warming and melting of the ice sheets triggered the release of CO2 from the oceans, which accelerated the demise of the ice age.”
Brook said the recent increase in CO2 via human causes is also warming the planet, “but much more rapidly.”
There is no significant CO2-GW. The real explanation is the reduction of cloud albedo by biofeedback. More later…..:o)
More clarity on the poorly named GHE;
http://drtimball.com/2013/a-greenhouse-as-analogy-for-the-atmosphere-is-completely-wrong/
As presented, it seems the release of CO2 was a by-product, not a cause, of warming.
Scientists say that changes in the amount of solar energy triggered the warming of West Antarctica and the subsequent release of carbon dioxide (CO2) from the Southern Ocean
=====================
So the sun was the cause, and CO2 the effect.
And why is the warming since the LIA not the cause of the release of CO2 today? How is it that warming in the past released CO2, but now warming doesn’t release CO2. Instead if must be humans.
Same excuse doctors use when they can’t find the cause of a disease – it must be something the patient is doing that is causing the problem.
Ian W says:
August 14, 2013 at 3:25 pm
Add some CO2 and the CO2 warmed by collision – radiates infrared cooling the Nitrogen Oxygen mixture.
============
this is why the atmosphere cools with altitude. otherwise it would be isothermal.
The last glaciation period ended because the earth’s eccentricity was at its peak, as was its obliquity, and the precession of the earth made it receive the maximum solar input to the northern hemisphere in the summer. The periods of glaciation and their end have little to do with what happens in the southern hemisphere, but rather, everything to do with what happens north of the equator. I can not believe these people call themselves scientists.
ferd berple says:
August 14, 2013 at 4:04 pm
this is why the atmosphere cools with altitude. otherwise it would be isothermal
================
this process would continue except that vertical circulation kicks in to limit the drop in temperature to the lapse rate – which is governed by gravity. objects can only fall so fast, so the conversion of PE to KE and thus temp/altitude is bound to gravity, moderated by the phase change of water.
This headline says differently:
“Earth Orbit Changes Key to Antarctic Warming That Ended Last Ice Age”
“the warming in West Antarctica 20,000 years ago is not explained by a change in the sun’s intensity. Instead, how the sun’s energy was distributed over the region was a much bigger factor. It not only warmed the ice sheet but also warmed the Southern Ocean that surrounds Antarctica, particularly during summer months when more sea ice melting could take place.”
Twas the Sun and then the CO2
http://www.sciencedaily.com/releases/2013/08/130814132228.htm
No, it was not the Sun. The Earth’s axil wriggle in its orbit around the Sun caused the initial warming. And when it wriggles back the Earth’s tilt will bring about cooling. The Sun didn’t do anything but sit there and beam.
So earlier warming of west Antarctica triggered loss of sea ice there and this became general regional warming that degassed CO2 from the southern ocean and terminated the most recent ice age?` Still seems cold down there…..lots of ice all over the place (over 3000m of it where they drilled). Do we have another end of the ice age each time the major oceans’ decadal oscillations turn over, diminishing west Antarctic sea ice?
This reads like a dang Monty Python script..
“Bring out the Holy Hang Grenade” Thous shall count to three, not four, and certainly not five”
Jim S
As a scientist with substantial knowledge of this topic I would be surprised if the mechanisms causing glacial terminations are as simple as you seem to imply. The global climate system is fairly (an understatement) complex, hence the reason why it has been so difficult to model. You should refrain from making such inane evidence-free statements as you are revealing the depth of your ignorance.
“No, it was not the Sun. The Earth’s axil wriggle in its orbit around the Sun caused the initial warming. And when it wriggles back the Earth’s tilt will bring about cooling. The Sun didn’t do anything but sit there and beam.”
It was changes in the the Sun’s insolation. Sun sun sun.
“Scientists say that changes in the amount of solar energy triggered the warming of West Antarctica and the subsequent release of carbon dioxide”
My “take aways”: 1) It’s the sun and 2) CO2 *follows* temperature.
The Milankovitch trigger for the end of the last glacial period is increased insolation at mid-latitudes in the NORTHERN hemisphere
Let’s see … the sun causes some melting over the NH glaciers. The glaciers retreat. The albedo is reduced causing more warming. Repeat. The glaciers eventually disappear. No CO2 required.
@Rob R
Rob R wrote: “As a scientist with substantial knowledge of this topic I would be surprised if the mechanisms causing glacial terminations are as simple as you seem to imply. The global climate system is fairly (an understatement) complex, hence the reason why it has been so difficult to model. You should refrain from making such inane evidence-free statements as you are revealing the depth of your ignorance.”
Jim S writes: My explanation is a far better one than suggesting that CO2 had any effect whatsoever in ending the last glaciation period or any of the other glaciation periods over the last 2.6 million years. Given the data record we have of CO2 concentrations, and the claim by AGW extremists that atmospheric CO2 has not risen above 280 ppm for the last 400,000, any claim that this amount of CO2 is significant enough to end a period of glaciation is ludicrous at best. Their own cockeyed theories stand against them.
If you want evidence as to what the conditions were 12,000 year ago regarding the Milankovitch cycles, and since you claim to be a scientist, then you should know that what I described was exactly where those cycles were. As to what the actual trigger(s) are that start or stop periods of glaciation, is still a mystery, granted. However, if one wants to even imagine that CO2 has much to do with abrupt climate temperature changes, in my opinion, they should be stripped of holding the honour of being called a “scientist.”
Eliza says:
August 14, 2013 at 2:58 pm
We may be observing the first effects of enlargement of antarctica on reach of cold air masses into tropics!
http://wxmaps.org/pix/sa.00hr.html
Probably nonsense if you check back to previous years LOL
Reply; This cold air invasion is the direct result of the lunar declinational tidal effects in the atmosphere, moon will be at maximum culmination South extent on the 16th. This atmospheric surge in cold air mass will peak one or two days later, happens every SH winter.
Hello,
Any One ice core is as useless as any One NOAA near-surface mercury thermometer.
Apparently these folks can’t read the literature or they would realize that every study of the timing of warming vs CO2 in Antarctica shows that CO2 FOLLOWS warming, not the other way around. (for a good summary of these studies, see Jo Nova’s website). So how can CO2 be responsible for the warming if the warming came first? Even with modern warming, CO2 lags warming.
From 22,900 years ago to 17,500 years ago …
… CO2 increased from 189 ppm to 188 ppm.
Climate science math.
No science here . . . just a bunch of cats dancing around on a hot tin roof. Problem is, all their acrobatics only dig them in deeper.
A parallel piece of ignorance on the CBS Evening Propaganda tonight: Bob Schieffer says that California redwoods are growing faster than ever because of climate change, which is making the growing season longer.
Problem #1: “Growing season” doesn’t have much relevance in the climate of the Redwood Empire. It’s cool and damp the year round, frost is rare. In many areas you can go a whole year staying between 40 F and 55 F and have that same spread in any month of the year.
Problem #2: In general, growing seasons, where they are relevant, are getting shorter (corn belt planting a month late, in May, and threats of first frost later this month – yes, that’s August we’re talking about.) The same in Europe and Australia. Definitely not longer.
Problem #3: More rapid growth of redwoods would be expected, as for any other plant life, as the result of increased CO2 in the atmosphere and the resultant effects of fertilization and moisture retention.
Pardon me if I see a bit of a difficulty in Schieffer’s pontification.
Nice insight, Chad Wozniak. Basically, Schieffer lied, er, pardon me. READ a lie.
“CBS Evening Propaganda” — LOL.
Any book news? Composing/playing news? Has #23 come and gone? Hope it was happy.
Ivan says: @ur momisugly August 14, 2013 at 2:30 pm
“Brook said the recent increase in CO2 via human causes is also warming the planet, “but much more rapidly.”’
So the temperature is now increasing faster than at the end of last Ice Age, when it increased 7 or 8 degrees globally???
>>>>>>>>>>>>>>>>>>>>>>>>
Yeah, “Richard Alley, one of the world’s leading climate researchers and his colleagues found that the last ice age came to an abrupt end over a period of only three years and found local warmings as large as 16°C, occurred repeatedly during the slide into and climb out of the last ice age. “
http://www.amazon.com/Two-Mile-Time-Machine-Abrupt-Climate/dp/0691102961
Also SEE: “Abrupt Climate Change – Inevitable Surprises”, Committee on Abrupt Climate Change, National Research Council of the National Academy of Sciences, 2002, Dr. Alley Chair
http://www.nap.edu/openbook.php?isbn=0309074347
Some how I do not think we are seeing human caused warming of the planet, as high as 16°C.
Even Hansen, Mann and Jones together can’t manage that.
Did the author(s?) give any consideration to the possibility of geothermal activity in W. Antarctica?
Probably not; after all, what else could it be but CO2?