Releases may have speeded end of last ice age — and could act again![[]](https://i0.wp.com/www.eurekalert.org/images/clear.gif?resize=8%2C1){kind=spacer}
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IMAGE: This pictures shows the locations of cores showing Antarctic upwelling.
Natural releases of carbon dioxide from the Southern Ocean due to shifting wind patterns could have amplified global warming at the end of the last ice age–and could be repeated as manmade warming proceeds, a new paper in the journal Science suggests.
Many scientists think that the end of the last ice age was triggered by a change in Earth’s orbit that caused the northern part of the planet to warm. This partial climate shift was accompanied by rising levels of the greenhouse gas CO2, ice core records show, which could have intensified the warming around the globe. A team of scientists at Columbia University’s Lamont-Doherty Earth Observatory now offers one explanation for the mysterious rise in CO2: the orbital shift triggered a southward displacement in westerly winds, which caused heavy mixing in the Southern Ocean around Antarctica, pumping dissolved carbon dioxide from the water into the air.
“The faster the ocean turns over, the more deep water rises to the surface to release CO2,” said lead author Robert Anderson, a geochemist at Lamont-Doherty. “It’s this rate of overturning that regulates CO2 in the atmosphere.” In the last 40 years, the winds have shifted south much as they did 17,000 years ago, said Anderson. If they end up venting more CO2 into the air, manmade warming underway now could be intensified.
Scientists have been studying the oceans for more than 25 years to understand their influence on CO2 levels and the glacial cycles that have periodically heated and chilled the planet for more than 600,000 years. Ice cores show that the ends of other ice ages also were marked by rises in CO2.
Two years ago, J.R. Toggweiler, a scientist at the National Oceanic and Atmospheric Administration (NOAA), proposed that westerly winds in the Southern Ocean around Antarctica may have undergone a major shift at the end of the last ice age. This shift would have raised more CO2-rich deep water to the surface, and thus amplified warming already taking place due to the earth’s new orbital position. Anderson and his colleagues are the first to test that theory by studying sediments from the bottom of the Southern Ocean to measure the rate of overturning.
The scientists say that changes in the westerlies may have been triggered by two competing events in the northern hemisphere about 17,000 years ago. The earth’s orbit shifted, causing more sunlight to fall in the north, partially melting the ice sheets that then covered parts of the United States, Canada and Europe. Paradoxically, the melting may also have spurred sea-ice formation in the North Atlantic Ocean, creating a cooling effect there. Both events would have caused the westerly winds to shift south, toward the Southern Ocean. The winds simultaneously warmed Antarctica and stirred the waters around it. The resulting upwelling of CO2 would have caused the entire globe to heat.
Anderson and his colleagues measured the rate of upwelling by analyzing sediment cores from the Southern Ocean. When deep water is vented, it brings not only CO2 to the surface but nutrients. Phytoplankton consume the extra nutrients and multiply.
In the cores, Anderson and his colleagues say spikes in plankton growth between roughly 17,000 years ago and 10,000 years ago indicate added upwelling. By comparing those spikes with ice core records, the scientists realized the added upwelling coincided with hotter temperatures in Antarctica as well as rising CO2 levels.
In the same issue of Science, Toggweiler writes a column commenting on the work. “Now I think this really starts to lock up how the CO2 changed globally,” he said in an interview. “Here’s a mechanism that can explain the warming of Antarctica and the rise in CO2. It’s being forced by the north, via this change in the winds.”
At least one model supports the evidence. Richard Matear, a researcher at Australia’s Commonwealth Scientific and Industrial Research Organisation, describes a scenario in which winds shift south and produce an increase in CO2 venting in the Southern Ocean. Plants, which incorporate CO2 during photosynthesis, are unable to absorb all the added nutrients, causing atmospheric CO2 to rise.
Some other climate models disagree. In those used by the Intergovernmental Panel on Climate Change, the westerly winds do not simply shift north-south. “It’s more complicated than this,” said Axel Timmermann, a climate modeler at the University of Hawaii. Even if the winds did shift south, Timmermann argues, upwelling in the Southern Ocean would not have raised CO2 levels in the air. Instead, he says, the intensification of the westerlies would have increased upwelling and plant growth in the Southeastern Pacific, and this would have absorbed enough atmospheric CO2 to compensate for the added upwelling in the Southern Ocean.
“Differences among model results illustrate a critical need for further research,” said Anderson. These, include “measurements that document the ongoing physical and biogeochemical changes in the Southern Ocean, and improvements in the models used to simulate these processes and project their impact on atmospheric CO2 levels over the next century.”
Anderson says that if his theory is correct, the impact of upwelling “will be dwarfed by the accelerating rate at which humans are burning fossil fuels.” But, he said, “It could well be large enough to offset some of the mitigation strategies that are being proposed to counteract rising CO2, so it should not be neglected.”
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Prob with the image link, Anthony.
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The links no longer work. This one worked for me.
http://www.eurekalert.org/pub_releases/2009-03/teia-wsm030909.php
Jim
Come on!! Whattsup with that!!
“the intensification of the westerlies would have increased upwelling and plant growth in the Southeastern Pacific” Deserts have not changed dow here…
This is one of the last reels of some Sci-Fi hollywood movie (The last one will be named: “The anthropogenic cooling”..LOL
First, the image would not load so I found it here:
http://www.eurekalert.org/pub_releases/2009-03/teia-wsm030909.php
My first thought was: So what? Unless they are talking about 1000s of ppm of CO2 AND the positive feedbacks claimed by AGW folks, what difference would this make toward global warming. If the feedback is negative and the build up of CO2 is slow then maybe this will trigger the slow onset of a new ice age. Isn’t this the sequence: a long slow entrance to an ice age and than a more rapid end. So if it has been 17,000 since the beginning of the end of the last one, we should be looking for the trigger of the new one. Cheers!
If CO2 is in equilibrium between the atmosphere and the air, it doesn’t matter how much water is stirred, CO2 will neither be taken up or released by the water.
Additionally, since when has the increase in CO2 at the end of each ice age been “mysterious”? When water warms, it releases CO2. The stirring that this article postulates might increase the rate at which water is warmed and releases it’s CO2, but it is not a cause.
If the thesis behind this paper were valid, wouldn’t there be a big uptick in CO2 everytime there is an La Nina? That also involves cold waters from the deep being brought to the surface.
But the science is settled. Why do we need “further research”?
Well, it doesn’t surprise me that this particular research group would form such a conclusion:
So they are all peas from the same pod validating each others’ work.
The article makes no mention of the lag between temperature change and CO2 rise and implies that the CO2 rise was contemporary with the temperature change.
The crux of the article?
So it is someone angling for research money by publishing a paper with “at least one model” supporting the conclusion but leaving the question in doubt but nevertheless illustrating the “critical need” for “further research” (translated: critical need for more money).
You know for having a “Consensus”, every article about man-made global warming consists of a lot of “could”, “maybe”, “might”, “possible”, and especially “model”, but nothing too concrete.
Makes you wonder if the real consensus is “that we don’t know diddly about climate”.
First we’ve never heard of global warming until James Henson back in the early 80’s and as greenhouse gas C02 there were no automobiles on earth 17000 years ago.The automobile wasn ‘t invented until 1894 and there wasn’t but a few of them .Everyone rode by horse or walked.Where do these people come up with this to begin with?Maybe the horse caused the greenhouse gas.
But the ice cores show an 800 year lag not a 40 year lag before CO2 rises so I’ll worry about this one in the year 2809. My models bigger/better than yours AGW drivel, shame all of the models are hopeless.
This is another “well, DUH” story.
Many skeptics believe CO2 follows temperature, not the reverse.
If CO2 does follow temperature increases,
Then as the earth warms at the end of an ice age, the CO2 concentrations would rise also.
Nothing new here except more hype about the warming powers of CO2.
By the way it is real that deserts along the west coast of Peru have drecreased notably but this has been totally “anthropogenic”. Using wells deserts have been irrigated to cultivate crops like asparragus, paprika, grapes, etc. which are being exported mainly to the US market. Again, nothing to do with imaginary CO2 or whatever phantasies. La Nina is OK down here, raining and snowing high on the andes (so glaciers also returning to before the “warming hysteria” size)
I don’t think the issue should be on the research or the belief of the researchers on the quality of their science. It is the pecular spin that gets put on these things. It is like when I look at a cloud and see a Tennessee Walking Horse and they see a Unicorn. Uff Da!
I would like to know how surface winds cause any kind of significant deep water upwelling. I don’t see the mixing that is portrayed in the above article as very likely and for the reasons stated.
I would put the “study” and it’s conclusions as highly speculative if not science fiction.
Get Bob Carter to comment on this one – he’s a great friend of Science magazine, isn’t he?
1. Do we yet have concensus that higher carbon dioxide means higher temperatures, or that higher temperatures causes higher carbon dioxide?
2. What caused those wind shifts anyway?
3. Which ice cores were these and why is the lag between temperature and carbon dioxide so different to those reported by others before?
4. Has Dick Lindzen ever been asked to referee papers by Science?
5. As an MIT Prof, if the answer is ‘No!’, the question is: ‘why not?’
6. Was he asked to referee this one?
7. Can you get him to review this one for this site??!!
They never look at the big picture. It is more than common knowledge that CO2 gets released because of temperature increase regardless of where that CO2 was stored, if it was in the snow or in the water. Obviously it was not coming from cars or power plants.
If things started to get warmer because of the tilt, position, rotation, solar activity, or whatever, for sure the snow/ice covering the NE landmass also melted, slowly, revealing more land to be heated and transfering eventually that heat to the oceans. You can see a positive loop here but it is not sudden, it takes time.
Again, the rise of CO2 concentration is just an artifact of global warming, a natural concequence.
What triggered the end of the ice ages is the same that will trigger the next one… position and activity of the sun relative to the earth and frankly, there is nothing we can do about it… the forces in the universe are much stronger than we are (come to the Dark Side of the Force Luke!!!)
Sorry OT: Lindzen at the ICCC – meeting:
“With respect to better understanding the science, it is my view that the observations of almost a decade ago that outgoing long wave radiation associated with warmer surface temperatures was much greater than models predicted; this was as good evidence that model sensitivities were much too high as one could hope for.”
“What at least four groups all confirmed was that emitted heat radiation during the ‘90s was not only much greater than what models predicted, but also greater than what would have been expected if there were no feedback at all.”
Aren’t these interesting data worth a blogpost. Who are these four groups? Where are the data?
rickM (11:45:06) : regarding surface winds and upwelling
Consider in the Pacific Ocean west of South America. The huge SubTropical High Pressure (STHP) system spins out wind that blows northward along the coast. The Coriolis Force causes these winds to turn away from the coast and move northwestward. These winds become the SE Trades. This is in a part of the world where we might expect the surface waters to be warm. Instead, the warmth input there by high sun gets shunted away and the cold water below rises to fill the void. The air blowing across this cold (Humboldt) current takes up moisture and generates fog but the cold air doesn’t rise and so makes coastal Chile a cool foggy place. Northward along the coast of South America we get into the El Nino area. Search on some of these concepts.
Why would anyone care whether or not computer models support a hypothesis? shouldn’t we be asking does real world data support it?
Didn’t we recently have a discussion here about the shape of the temperature graphs vs the shape of the carbon dioxide concentration over time? could someone link me to it I can’t seem to find it? Should we revisit that issue if that analysis was correct at all this article is trivial isn’t it?
Oh dear. It seems that climatologists are so far into their models that they are no longer observing the real world.
It is quite true that the westerlies shifted poleward in both hemispheres during the warming spell but since 2000 they have been moving equatorward again and the climate establishment has failed to notice.
By my climate theories here:
http://climaterealists.com/news.php?tid=37
I make it clear that the mid latitude jets move poleward or equatorward depending on the global temperature TREND at any particular time.
When they shift poleward the air is warming globally and when they shift equatorward as now the air is cooling globally.
In my humble opinion the entire climate establishment is clueless and all those above wild speculations are wholly unfounded.
The latitudinal wind shifts are a natural part of normal global warming and cooling phases and nothing to do with us or CO2 except perhaps for a movement of a few miles poleward (as I suggest in one of my articles) to adjust the global heat budget to neutralise any warming caused by extra human CO2. Since the natural movements are in the order of hundreds of miles any human effect is insignificant.
I do hope they catch up with reality eventually.
Looks like the start of another discussion of whether the egg or the chicken came first.
The way I read it is that they are saying that major global warming was caused by an orbit shift. That warming may have stirred the ocean (through winds) so that a bit more CO2 was given off than warming would have done to the oceans anyway (warming H2O cause CO2 to come out of solution).
They then say that the extra CO2 caused by this upwelling is less than what man is giving off, which up to now, if you accept alarmist AGW theory (which I don’t) has only caused .6 degrees C warming.
Therefore, this upwelling was, at best, a bit player in the warming.
So it looks like they are backing away from AGW theory–Major warming is caused by orbit shift– and at the same time trying to justify additional funding of their research from the Climate Change funds.
I think it’s full of speculation and BS. Those scientists predicting this occurrence are again relying on computer projections and these are wildly unrealiable. I believe the colder PDO and AMO will sequester any additional CO2 released by the southern ocean never to be seen for centuries or millennia.
I wonder which is more accurate a AGW climate model or a Scientology e-meter?
What if the two were compared for precision? Would the AGW climate model fare better?