From the Massachusetts Institute of Technology:
While the Arctic Ocean is largely a carbon sink, researchers find parts are also a source of atmospheric carbon dioxide
For the past three decades, as the climate has warmed, the massive plates of sea ice in the Arctic Ocean have shrunk: In 2007, scientists observed nearly 50 percent less summer ice than had been seen in 1980.
Dramatic changes in ice cover have, in turn, altered the Arctic ecosystem — particularly in summer months, when ice recedes and sunlight penetrates surface waters, spurring life to grow. Satellite images have captured large blooms of phytoplankton in Arctic regions that were once relatively unproductive. When these organisms die, a small portion of their carbon sinks to the deep ocean, creating a sink, or reservoir, of carbon.
Now researchers at MIT have found that with the loss of sea ice, the Arctic Ocean is becoming more of a carbon sink. The team modeled changes in Arctic sea ice, temperatures, currents, and flow of carbon from 1996 to 2007, and found that the amount of carbon taken up by the Arctic increased by 1 megaton each year.
But the group also observed a somewhat paradoxical effect: A few Arctic regions where waters were warmest were actually less able to store carbon. Instead, these regions — such as the Barents Sea, near Greenland — were a carbon source, emitting carbon dioxide to the atmosphere.
While the Arctic Ocean as a whole remains a carbon sink, MIT principal research scientist Stephanie Dutkiewicz says places like the Barents Sea paint a more complex picture of how the Arctic is changing with global warming.
“People have suggested that the Arctic is having higher productivity, and therefore higher uptake of carbon,” Dutkiewicz says. “What’s nice about this study is, it says that’s not the whole story. We’ve begun to pull apart the actual bits and pieces that are going on.”
A paper by Dutkiewicz and co-authors Mick Follows and Christopher Hill of MIT, Manfredi Manizza of the Scripps Institute of Oceanography, and Dimitris Menemenlis of NASA’s Jet Propulsion Laboratory is published in the journal Global Biogeochemical Cycles.
The ocean’s carbon cycle
The cycling of carbon in the oceans is relatively straightforward: As organisms like phytoplankton grow in surface waters, they absorb sunlight and carbon dioxide from the atmosphere. Through photosynthesis, carbon dioxide builds cell walls and other structures; when organisms die, some portion of the plankton sink as organic carbon to the deep ocean. Over time, bacteria eat away at the detritus, converting it back into carbon dioxide that, when stirred up by ocean currents, can escape into the atmosphere.
The MIT group developed a model to trace the flow of carbon in the Arctic, looking at conditions in which carbon was either stored or released from the ocean. To do this, the researchers combined three models: a physical model that integrates temperature and salinity data, along with the direction of currents in a region; a sea ice model that estimates ice growth and shrinkage from year to year; and a biogeochemistry model, which simulates the flow of nutrients and carbon, given the parameters of the other two models.
The researchers modeled the changing Arctic between 1996 and 2007 and found that the ocean stored, on average, about 58 megatons of carbon each year — a figure that increased by an average of 1 megaton annually over this time period.
These numbers, Dutkiewicz says, are not surprising, as the Arctic has long been known to be a carbon sink. The group’s results confirm a widely held theory: With less sea ice, more organisms grow, eventually creating a bigger carbon sink.
A new counterbalance
However, one finding from the group muddies this seemingly linear relationship. Manizza found a discrepancy between 2005 and 2007, the most severe periods of sea ice shrinkage. While the Arctic lost more ice cover in 2007 than in 2005, less carbon was taken up by the ocean in 2007 — an unexpected finding, in light of the theory that less sea ice leads to more carbon stored.
Manizza traced the discrepancy to the Greenland and Barents seas, regions of the Arctic Ocean that take in warmer waters from the Atlantic. (In warmer environments, carbon is less soluble in seawater.) Manizza observed this scenario in the Barents Sea in 2007, when warmer temperatures caused more carbon dioxide to be released than stored.
The results point to a subtle balance: An ocean’s carbon flow depends on both water temperature and biological activity. In warmer waters, carbon is more likely to be expelled into the atmosphere; in waters with more biological growth — for example, due to less sea ice — carbon is more likely to be stored in ocean organisms.
In short, while the Arctic Ocean as a whole seems to be storing more carbon than in previous years, the increase in the carbon sink may not be as large as scientists had previously thought.
“The Arctic is special in that it’s certainly a place where we see changes happening faster than anywhere else,” Dutkiewicz says. “Because of that, there are bigger changes in the sea ice and biology, and therefore possibly to the carbon sink.”
Manizza adds that while the remoteness of the Arctic makes it difficult for scientists to obtain accurate measurements, more data from this region “can both inform us about the change in the polar area and make our models highly reliable for policymaking decisions.”
This research was supported by the National Science Foundation and the National Oceanic and Atmospheric Administration.
Written by Jennifer Chu, MIT News Office
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Ivor Ward says:
December 4, 2013 at 10:27 am
and others…
For the carbon cycle, it is common use to express quantities in PgC – Petagram carbon or in more common use in the early days in – GtC Gigaton carbon (which is the same quantity: 10^15 g or 10^9 ton). That is because it is mainly CO2 in the atmosphere, but once in the oceans it is less than 1% CO2, the rest is bicabonate (90%) and carbonate (9%) ions. In vegetation it is even far more diversed as sugars, starch, cellulose, lignin, proteins, plant hormones,…
To make a mass balance possible in that diversity, one uses carbon, as that is the element of interest and isn’t destructed or created, whatever the form in what it is transformed on its path through nature.
They had to torture the models until they started saying what was expected.
Ivor Ward says:
December 4, 2013 at 10:27 am
“”While the Arctic Ocean is largely a carbon sink, researchers find parts are also a source of atmospheric carbon dioxide””
What are they talking about? Carbon or Carbon Dioxide? Do they even know the difference?
Carbon sinks bind carbon in multiple forms from humus and charcoal to methane clathrates. The principle carbon binders though are green plants and they use photosynthesis. The normal source for that carbon is atmospheric CO2, or dissolved CO2 in aqueous solution for algae. When that “carbon” comes back out of the “sink,” it is typically in the form of CO2 or methane – mostly CO2 and the methane oxidizes to CO2 fairly quickly. So, all in all, the wording is clear enough and properly distinguishes between “carbon sinks” and CO2.
Their very first words……
“For the past three decades, as the climate has warmed”
Seriously?? And they want me to keep reading !!!!!
There has been ONLY one single warming event in the last 30 years.
The rest of the time there has been pretty close to .. NONE !
Is this the same crew of modelers from MIT that were paid $400K by the White House to produce models that guaranteed that Obamacare would work?
Ferdinand Engelbeen: thanks for pointing out Doug Proctor’s error. It won’t help the credibility of climate sceptics if more of them start believing that recent minor variations in mean ocean temperature can account for large changes in atmospheric CO2. And thanks for your nice clear graphic. It’s good to have another real scientist commenting here.
Thanks for the Brief Anthony. It goes along with my research and gives my thoughts and observations “a leg up”.
“Now researchers at MIT have found that with the loss of sea ice, the Arctic Ocean is becoming more of a carbon sink.”
That sentence is a lie. They have not found anything.
“The team modeled changes in Arctic sea ice, temperatures, currents, and flow of carbon from 1996 to 2007, and found that the amount of carbon taken up by the Arctic increased by 1 megaton each year.”
Again, with the found, when referring not to observations, but to model results.
Model results are not findings. Model results are hypotheses. Hypotheses may be confirmed (or refuted) by findings. Findings are observations of the real world. Data.
They lie about what they are doing, even on such simple matters, and they wonder why they aren’t trusted.
“Now researchers at MIT have found that with the loss of sea ice, the Arctic Ocean is becoming more of a carbon sink.”
BS – at least on what is covered here – they didn’t “find” anything. It sounds like the have an untest model that has provided some unconfirmed results. Tell me how they confirmed the accuracy of their models and then we can discuss whether they “found” anything.
Today’s sea ice figs show the Arctic at minus 619,000 sq km…which means a recovery still in the process and Antarctica is plus 1,308,000 sq km….therefore plus 689,000 sq km overall. Current global sea ice is now so far above the mean average 79-08 that it stands as the 7th largest area of sea ice from the last 35 years.
The results point to a subtle balance: An ocean’s carbon flow depends on both water temperature and biological activity.
‘Subtle’ balance? These are the 2 primary parameters for carbon ‘flow’ into and out of the oceans. I thought this was well established, ‘settled science’!
Definition: Subtle, adjective, not loud, bright, noticeable, or obvious in any way
They just ‘noticed’ this now?
Ferdinand Engelbeen says:
December 4, 2013 at 9:00 am
http://www.ferdinand-engelbeen.be/klimaat/klim_img/seasonal_CO2_d13C_MLO_BRW.jpg
Ferdinand,
Please provide the full descriptors for the acronyms ‘MLO’ (Mauna Loa?) and ‘BRW’ (???), so I can put the graphical information provided into context.
Thank You for citing the Northern Hemisphere vegetative growing season as the primary correlation/cause for the annual CO2 delta ppmv at Mauna Loa. I knew I had stumbled across this information in the past but you saved me (and others, I suspect) the time needed to track it down again!
Your posts are informative – Thanks!
MtK
Yawn. I have little interest in work motivated by the idea that CO2 is harmful or capable of warming the atmosphere. There’s inherently a huge chance that their work is little more than used toilet paper.
Manizza traced the discrepancy to the Greenland and Barents seas, regions of the Arctic Ocean that take in warmer waters from the Atlantic. (In warmer environments, carbon is less soluble in seawater.) Manizza observed this scenario in the Barents Sea in 2007, when warmer temperatures caused more carbon dioxide to be released than stored.
Wait a minute. Is that actual observation or model observation? Something tells me it’s the latter. In which case, it’s just so much fantasy.
Warming of the Arctic Ocean adds a carbon sink of a megaton per year? That’s a drop in the bucket for compared to recent years annual ocean sinking of around 2.4 gigatons, maybe ~2.5 gigatons per year lately.
Cite for gigatons: http://www.tyndall.ac.uk/global-carbon-budget-2010
Find a sink every chance you get. Ignore the other half of the ocean carbon cycle which returns 12C to the water and the atmosphere in unknown proportions since we can’t be bothered to measure it. Allege that the very same Carbon being “sunk” is also causing the hot polar anomalies that reduce the hemispheric gradient and increase Rossby wave amplitude causing extreme weather…
Hmmm… I wasn’t aware that anybody had real long-term data that determined which geochemical & biological processes actually dominate CO2 mass exchange over large areas of the arctic – or any other area of the globe.
My error since I thought they just pulled numbers from their collective asses….
DOH … WAIT !!!
Mac the Knife says:
December 4, 2013 at 4:55 pm
“Ferdinand,
Please provide the full descriptors for the acronyms ‘MLO’ (Mauna Loa?) and ‘BRW’ (???), so I can put the graphical information provided into context.”
I assume BRW is Barrow, Alaska.
What I want to know is why are those scientists who told us the science was settled not being held accountable for the overtly fraudulent claims they made. All we need is a whistle blowers immunity charter to prove that they did know the claims were false.
Also this in no way explains the hot spots in the NASA sea anomaly data file AMSRE_SSTAn_M-MOD_LSTAD_M.
Frankly, all you need to know about this ‘study’ and the field that produced it is to be found right here:
“People have suggested that the Arctic is having higher productivity, and therefore higher uptake of carbon,” Dutkiewicz says. “What’s nice about this study is, it says that’s not the whole story. We’ve begun to pull apart the actual bits and pieces that are going on.”
Think about what she says there, and how she says it: “What’s nice about this study is …”
What an odd thing to say about a scientific paper. She identifies that her primary interest in this study is that it provides a talking point against a negative feedback. She finds that is ‘nice’ about this study.
They have no shame. None.
I thought the NH vegetation was in New Hampshire…
Mac the Knife says:
December 4, 2013 at 4:55 pm
MLO indeed is Mauna Loa
BRW is Barrow (Alaska, USA) coastal in the Arctic Ocean.
These acronyms are the official ones used by NOAA for a lot of stations. Here 86 stations that take regular flask samples, including their LON-LAT coordinates, but several of them also have continuous monitoring. NOAA itself maintains 4 of the “baseline” stations, but also measures (flask) samples of other stations: Barrow (BRW), Mauna Loa (MLO), American Samoa (SAM) and the South Pole (SPO), other stations are maintained by different groups of different countries.
Many data (discrete and continuous, land based, airborne and ocean atmospheric measurements) for different trace gases can be plotted and downloaded via the “carbon tracker” of NOAA:
http://www.esrl.noaa.gov/gmd/dv/iadv/
Brian says:
December 5, 2013 at 6:36 am
I thought the NH vegetation was in New Hampshire…
No problem, I thought once that Washington DC was the capital of Washington state…
Ferdinand Engelbeen says:
December 5, 2013 at 8:12 am
Never think your memory is accurate… SAM was the acronym for American Samoa used by the Scripps Institute where Keeling Sr. started the CO2 measurements over 50 years ago. Since NOAA coordinates the worldwide CO2 data gathering, they use SMO for Samoa…
Coldish says:
December 4, 2013 at 12:23 pm
“It won’t help the credibility of climate sceptics if more of them start believing that recent minor variations in mean ocean temperature can account for large changes in atmospheric CO2.”
According to this chart, the change in temperature over the past 50 years has accounted for a slope in dCO2/dt of about 0.15 ppmv/month/(50 years) = 0.036 ppmv/year^2. That accounts for about 0.5 * 0.036 * 50^2 = 45 ppmv out of a total rise of about 75 ppmv. The base level of dCO2/dt in 1963 was about 0.05 ppmv/month which, in 50 years accounts for 0.05 * 12 * 50 = 30 ppmv.
Such a relationship can arise easily. It is the same principle as for a transistor in an amplifier. The transistor does not actually amplify the incoming signal. It merely modulates the flow of a much larger signal in proportion to the incoming signal. Just so, it is not the temperature driving CO2 accumulation, it is the temperature modulation of a steady flow into the atmosphere from an, as yet, unknown source, but which I expect is related to deep ocean upwelling, as explained here.
This temperature modulated relationship accounts for essentially the entire rise in CO2 which has been observed in the past half century or so. It leaves little room for significant human influence. Again, such a result can arise easily if sink activity is very active, as it evidently is. This is a very basic, typical, and unremarkable type of behavior consistent with dynamic feedback systems such as we employ every day in high tech devices to mitigate the influence of outside disturbances on the performance of the device. It is so typical and usual that I have no qualms in asserting that, this is what is happening, and humans are having little effect on atmospheric CO2 levels.
In the near future, if temperatures continue their stasis or decline, it will become obvious to all and undeniable, as atmospheric CO2 accumulation is diverging from the virtual accumulation of emissions, and that divergence will accelerate with non-increasing temperatures and increasing emissions.