LEAKING CO2: Soil bacteria are rapidly converting thawing permafrost into carbon dioxide emissions.
Image: Flickr/subarcticmike
Sunlight is speeding up the conversion of Arctic soil carbon into carbon dioxide, raising the possibility that future warming could occur at a much faster pace, according to a new study.
Scientists generally agree that higher temperatures increase the likelihood of collapses of long-frozen Arctic ground, or permafrost, creating large holes in the tundra and landslides. But there has been less understanding of how long-buried carbon in the permafrost behaves when suddenly exposed to the sun's rays after such collapses, which are caused by the melting of ice-rich soils.
"We once thought that maybe permafrost soils would just kind of thaw quietly in place," said Rose Cory, an environmental sciences and engineering assistant professor at the University of North Carolina, Chapel Hill, and co-author of the study, published yesterday in the Proceedings of the National Academy of Sciences.
Previously, it was unknown whether permafrost carbon would react little to sunlight when finally released from its resting spot, and would instead flow to the Arctic Ocean with little immediate impact on the atmosphere, she said.
"The conversion to CO2 is going much faster than previously thought," she said.
It is important to understand the dynamic, she said, because permafrost is such a rich potential source of the greenhouse gas. If all the world's permafrost melted, it could double the amount of heat-trapping carbon dioxide in the atmosphere, she said.
The study demonstrates another feedback caused by warming -- high temperatures melt Arctic soil, which then releases even more carbon dioxide, helping create additional warming, the researchers said.
Sunlight and bacteria at work
The scientists sampled 34 sites in Arctic Alaska, including places where the land surface has collapsed, exposing long-buried soils. They found that sunlight increases the bacterial conversion of soil carbon to carbon dioxide by at least 40 percent compared to soil that remains in the dark.
Similarly, sunlight exposure increases the conversion of ancient permafrost carbon to CO2 by as much 40 percent in comparison to carbon already in the landscape system, Cory said. That existing carbon typically comes from annual thawing of the thin, active layer of soil resting on top of the permafrost, she said.
The collapses of Arctic soil, also known as thermokarst failures, are at the root of the process.
By stirring up the landscape, those failures cause carbon long stored in permafrost to be "mixed up" from depth, according to Cory. The Arctic is warming about twice as fast as the global average, according to scientists.
"We know that these thermokarst failures are going to be more and more common as time goes on," she said.
At the surface, the exposed soil carbon then absorbs sunlight, which breaks it down into compounds easily respired as carbon dioxide by bacteria. Most of this carbon-to-CO2 process via bacteria occurs in water pathways -- small streams, rivers and ponds -- fanning out from the large, erosional holes in the ground created from melted soil, she said.
One hypothesis of why ancient carbon is so sensitive to sunlight is that bacteria prefer carbon to be "somewhat baked," but not "excessively baked," said Cory. If organic carbon is in surface waters for too long, it becomes less susceptible to sunlight, she said.
'Huge stocks' of carbon remained untapped
The conversion to CO2 occurs via ultraviolet radiation, meaning it can still occur on cloudy days, she said. It doesn't require what the average person thinks of as "sunny," she said.
Laurence Smith, a geography professor at UCLA who did not participate in the research, said the paper is an "interesting addition" to existing knowledge of Arctic soil carbon.
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15 Comments
Add Comment"The study demonstrates another feedback caused by warming -- high temperatures melt Arctic soil, which then releases even more carbon dioxide, helping create additional warming, the researchers said."
Reply | Report Abuse | Link to thisOkay climate deniers...how do you explain THIS away to absolve your fossil fuel companies of responsibility for disrupting our climate? You keep asking for proof of the feedbacks that confirm the dire warnings that we need to reduce emissions PRONTO...Well, this study is just a small piece of the MOUNTAIN of evidence you repeatedly DENY even exists.
Sorry, the fossil fuel companies that spoonfeed this misinformation to you are wrong. Now either get with the program and work towards common sense solutions to this problem, or get out of the way so that the realists in this world can handle it.
sault
Reply | Report Abuse | Link to thisThis may have new information for you, but it has been noted for years that variations in the non human natural release of CO2 far exceed human contributions.
When there are increases in temperature microbs in the soil release additional CO2. This has nothing to do with AGW. Are you somehow trying to imply that temperatures do not vary when humans do no release CO2? That is pretty silly isn't it? The situation is not isolated to the tundra btw.
Hi Sault:
Reply | Report Abuse | Link to thisI have the utmost respect for your comments and have followed many of your blog entries over the years. However, this one is not as well crafted or filled with your normally flawless logic and data so many of us enjoy.
It is my personal belief that CO2 has something to do with climate change or whatever we are calling it today, but it is certainly not the WHOLE story. The problem as I see it is that there are many contributing factors effecting our climate. I would have found this study to be much more compelling if it had concluded that X number of tons of CO2 were being released AFTER subtracting the additional carbon being absorbed by the newly formed grasses growing on the tundra. I didn't see anything in the study that measured the effect of this new vegetation vs the carbon released. However, I only read this SA article and not the whole study.
To me the terms "Global Warming" and "Climate Change" are problem statements not SOLUTION statements and I am really getting tired of reading more problem statements. I can't speak for anyone else but isn't it about time we start studying and promoting SOLUTIONS. I want to promote solutions like the restructuring of our transportation sector, promoting conservation, making everything more efficient and of course renewable energy systems. These and many other actions are solutions not just ANOTHER CO2 paper. I am totally bored with another CO2, blah, blah, blah report.
Lets start studying how to clean up our air and water. That is something the American people can and WILL support. The average American doesn't give a hoot about Global Warming or Climate Change because they don't feel empowered to do anything about it. That is something they believe scientists do. Give the people something they can do and they WILL DO IT. Just take for example the progress we have made in the last 10 years in changing the attitudes of the people to support renewable energy. Now over 75% of the American people believe renewables are the right way to go. That's what we need, not more reports on CO2.
In closing please do not take my comment as a negative. My only intention is to begin to focus our attention on solutions instead of more problem reports. Negativity solves almost nothing.
@Sisko- Of course temperature varies whether people are present or not, and bacteria and warm soil full of plant matter make CO2. The point is, barring some huge new volcanic eruption, CO2 production and deposition have been in close balance since the last ice age. While natural sources produce 20 times more CO2 than humans, because of the close balance, adding 2% a year is cumulative. Temperature on average is going up, as it increases, at some point several huge CO2 sinks like tundra and hydrates are going to release, and then we're really going to be in trouble.
Reply | Report Abuse | Link to this@tomgarven- People have proposed many plans to mitigate CO2, they just keep getting shot down those interested in maintaining the current system. This isn't really a negative report- we have to get a good handle on sources for CO2 to get a better idea how much and how fast things might change. The greater the risk, maybe the sooner actual reductions on our part will happen.
Mudphud- I am not doubting that humans are contributing to increased atmospheric CO2. I do doubt that there is reliable evidence that this is a bad thing and greatly doubt that we can do anything to reduce CO2 emissions enough to have any significant or even measureable impact on the climate.
Reply | Report Abuse | Link to thisWorldwide, CO2 emissions will continue to increase as countries develop and their citizens want and gain access to electricity and personal transportation. My core question revolves around what makes sense to do in response to this perceived issue?
Imo, the most sensible possible action in a world with limited resources is for countries to build and maintain robust infrastructure. This reduces the harms that can result from bad weather. We do not know if, when or where bad weather will occur. Spending very limited resources to do something that we know will yield no result is simply stupid. That would be a fair description of most climate mitigation proposals. Spend limited funds doing something that will not do anything to prevent harm from bad weather.
Sisko wrote, "When there are increases in temperature microbs in the soil release additional CO2. This has nothing to do with AGW."
Reply | Report Abuse | Link to thisDoes the melting tundra have anything to do with GW, if not AGW? You only believe it has nothing to do with AGW, because you do not believe AGW is real. Why not say that. Your statement sounds like you believe AGW is real and significant but it has nothing to do with the melting tundra.
The melt in the tundra most likely has been affected by AGW but we cannot reliably determine to what extent.
Reply | Report Abuse | Link to thisI am doubtful that the amount of warming to date due to AGW was the significant cause of the increase in CO2 release. In the studies I have read they were warming the soils by several degrees by putting cables into the soil. There was evidence of additional CO2 being released but it stabilized over time. The amount of warming to date due to AGW would not have raised the soil temperature by the several degrees done in the studies. It is entirely possible that natural variations in temperatures over time would have raised temperature in specific areas enough however.
Do you agree that the global temperatures have increase on average by approximately 0.8C in the last hundred years with most of that increase coming since 1980? And that Arctic temperatures have increase by approximately 2.5C in the last hundred years?
Reply | Report Abuse | Link to thisHow much of that do you believe was natural vs anthropogenic? 95% natural? 60% natural? 25% natural? Is it possible the exclusively natural variations may have led to a decrease in temperatures? e.g. -50% natural?
"I am doubtful that the amount of warming to date due to AGW was the significant cause of the increase in CO2 release."
Reply | Report Abuse | Link to thisWhere's the link to these "studies"? This sounds nothing like what they did in this study:
"The scientists sampled 34 sites in Arctic Alaska, including places where the land surface has collapsed, exposing long-buried soils. They found that sunlight increases the bacterial conversion of soil carbon to carbon dioxide by at least 40 percent compared to soil that remains in the dark."
When the land breaks apart because the permafrost is melting, it exposes carbon in the soil to sunlight. That sunlight causes 40% more CO2 release than if the soil was in the dark. Did you even read the article?
People like you are just spouting off the "second line of defense" that fossil fuel companies are putting out there to delay action even further. To deny that the warming is occurring or that CO2 emissions are causing it is completely laughible, even to most of the general public. The party line has now morphed into obfuscation about the magnitude of the climate disruption our emissions are causing. And going against what the science is SCREAMING at us, you put forward the ABSURD claim that we can't really do anything about it. What an intellectually lazy and reckless mindset to be inflicting upon others!
I think you're hitting on the whole reason climate denial is spread in the first place. We can't even begin discussing solutions properly because somebody ALWAYS comes in here, trolling around talking about Al Gore or the conspiracy of climate scientists to fool the whole world so they can get grant money.
Reply | Report Abuse | Link to thisStatements like "Climate change is a serious problem and human emissions are causing it" is polling at over 50%, especially after all the wacky weather we've been having over the last few years. And support for renewable energy is over 70%. So people have a general handle on the problem despite the fossil fuel companies' best efforts to confuse them.
As for solutions, Ireland, British Columbia and Sweeden have had some success with a Carbon Tax. If the revenues are used to lower payroll taxes then it is highly progressive and leads to higher job growth over time. Since the overwhelming majority of temperature increases since 1970 are due to human activity, and since higher temperatures / disrupted weather patterns have a cost associated with them, the carbon tax helps to correct for the MASSIVE market failure that is climate change.
We could also encourage smart growth so that people can live near their jobs and stores / restaurants / etc. as well and they can have a variety of transportation options to get to where they want to go. One way to make this happen is to ratchet up federal and state fuel taxes until there is enough money coming in to AT LEAST bring our roads, bridges, tunnels, etc. up to MINIMUM safety standards. We've been withdrawing from our infrastructure dividend laid down in the 20th Century for nearly 30 years now.
New building construction should be LEED silver AT LEAST with incentives for going LEED platinum.
Trade policy should start to give "free rider" polluters less preference compared to countries that agree and accomplish emissions reductions. They need our money more than we need their pollution.
Finally, we can also mandate that oil and gas drillers must substantially reduce methane leakage from their operations (and repeal their exemptions from the Clean Air / Water Acts). Pollution regulations on power plants should be tightened to lower the climate, health, worker productivity and property damage they cause as well as thousands of premature deaths.
mudphud said in part: "The greater the risk, maybe the sooner actual reductions on our part will happen.".
Reply | Report Abuse | Link to thisWell I certainly hope you are correct. However, I would feel much better if we had some plans in place to:
1. Look for and convince the American people that a Carbon Tax would have been better than a Cap and Trade bill that never made it through Congress. Even now after California has implemented their Cap and Trade program; more and more people are predicting it will fail. Instead of lobbying for Cap and Trade in Washington, maybe there should have been a fall-back plan in place for a Carbon Tax. The American people don't trust trading smoke since that is really difficult to do. It is far easier for them to track tax dollars.
2. Almost nothing gets done in America without the support of the media. There should be a plan in place to train and interface directly with media types and journalists about the consequences of waiting and the meaning of these types of reports. Instead of just saying - if we don't act soon the world will end - we need to begin to inform the people by getting in their face. I watch the evening news everyday on at least 2 different media outlets and I can't even remember the last time I saw something about climate change. Oh sure I saw the consequences of the hurricane in N.York but I didn't hear a single journalist say the storm was caused by global warming. Until we have strategies in place to stimulate the media - nothing much is really going to happen. While I certainly enjoy reading and blogging on SA, we [the readers and bloggers] are probably only a small fraction of 1% of the population. Almost no one sees what we write and even if they did, they may not understand what we are trying to say. Effective communication involves certain social skills and personal contact with others. I freely admit that as an engineer that is NOT my strong suit, LOL.
3. Politicians. Lets face it - at the current time corporate America and the Oil Companies run this country. They are the ones with the deep pockets that tell Washington what to do. If we the people are going to be successful we need action plans to do things like: Implementing term limits. Educating people to vote for the person that best represents their views and not some political party. We need an action plan that starts tracking the contributions of corporations to political candidates. We need to correct the mistake made by our Supreme Court that considers a corporation people.
These are but a few of the actions we need to be taking if we are every going to start making some progress. There are however hundreds of things we can be doing NOW instead of waiting for the other shoe to drop.
Thank you very much for the positive feedback.
Now that is a good posting. What do you think is more harmful. CO2 or Methane or is it even possible to know at this point in time.
Reply | Report Abuse | Link to thisI have this gut feeling that Methane is going to be a much bigger problem since it is so much more harmful per cubic foot/ton.
You thoughts please.
It isn't an either / or. Both CH4 and CO2 contribute to warming but in different ways. CO2 stays in the atmosphere longer AND changes ocean chemistry. Methane is more powerful in warming terms per ton, but is released by humans at an order of magnitude or so lower rate. Human caused warming is ALREADY kicking off methane outgassing from permafrost areas and if the "Clathrate Gun" Hypothesis is correct, then our initial warming could kick off a DANGEROUS level of warming and other knock-on effects through feedback mechanisms like this.
Reply | Report Abuse | Link to thisThank you.
Reply | Report Abuse | Link to thisGood points. We also need to eliminate First-Past-The-Post voting systems. The most stupid and idiotic method of selecting a politician. The only justification for it was in the days of the horse-and-buggy when there was no computers and the fastest communication was pony express.
Reply | Report Abuse | Link to thisA much better system is Instant Run-Off Voting. Run-Off voting systems are common worldwide and that is how many parties select their candidate but curiously avoid allowing multiple political parties/independents to have the same opportunities in the MUCH more important election. Run-Off voting gives alternative views a chance to blossom and gives the public a safe way to boldly register dissatisfaction with the current totally corrupted politicians & political parties. The DemoCRIPPS or the ReBLOODicans. The Instant Run-Off Voting is just a quicker and simpler way than having to have multiple ballots like many countries do. The US wastes 8 months in a nutty election campaign for president, but won't allow voters to have A REAL CHOICE in candidates. Just ridiculous.
FPTP voting caused supporters of the Green Party to give us 8 yrs of the Worst President in US history - Chimp & his sidekick Darth Cheney, a disaster wrought upon the entire World thanks to the Green Party & First-Past-The-Post voting.
Instant Runoff or Alternative Voting systems explained:
youtube.com/watch?feature=player_embedded&v=3Y3jE3B8HsE
en.wikipedia.org/wiki/Instant-runoff_voting_in_the_United_States