Climate change may happen more quickly than expected

ScienceDaily (Nov. 30, 2011) — As global temperatures continue to rise at an accelerated rate due to deforestation and the burning of fossil fuels, natural stores of carbon in the Arctic are cause for serious concern, researchers say.

In an article scheduled to be published Dec. 1 in the journal Nature, a survey of 41 international experts led by University of Florida ecologist Edward Schuur shows models created to estimate global warming may have underestimated the magnitude of carbon emissions from permafrost over the next century. Its effect on climate change is projected to be 2.5 times greater than models predicted, partly because of the amount of methane released in permafrost, or frozen soil.

"We're talking about carbon that's in soil, just like in your garden where there's compost containing carbon slowly breaking down, but in permafrost it's almost stopped because the soil is frozen," Schuur said. "As that soil warms up, that carbon can be broken down by bacteria and fungi, and as they metabolize, they are releasing carbon and methane, greenhouse gases that cause warmer temperatures."

As a result of plant and animal remains decomposing for thousands of years, organic carbon in the permafrost zone is distributed across 11.7 million square miles of land, an amount that is more than three times larger than previously estimated. The new number is mainly based on evidence the carbon is stored much deeper as the result of observations, soil measurements and experiments.

"We know the models are not yet giving us the right answer -- it's going to take time and development to make those better, and that process is not finished yet," Schuur said. "It's an interesting exercise in watching how scientists, who are very cautious in their training, make hypotheses about what our future will look like. The numbers are significant, and they appear like they are plausible and they are large enough for significant concern, because if climate change goes 20 or 30 percent faster that we had predicted already, that's a pretty big boost."

The survey, which was completed following a National Science Foundation-funded Permafrost Carbon Network workshop about six months ago, proposed four warming scenarios until 2040, 2100 and 2300. Researchers were asked to predict the amount of permafrost likely to thaw, how much carbon would be released, and what amount would be methane, which has much more warming potential than carbon dioxide.

The occurrence of carbon in northern soils is natural and the chemical does not have an effect on climate if it remains underground, but when released as a greenhouse gas it can add to climate warming. However, humans could slow warming temperatures as the result of greenhouse gas emissions from deforestation and the burning of fossil fuels, which are what speed up the process of permafrost thaw.

"Even though we're talking about a place that is very far away and seems to be out of our control, we actually have influence over what happens based on the overall trajectory of warming. If we followed a lower trajectory of warming based on controlling emissions from the burning of fossil fuels, it has the effect of slowing the whole process down and keeping a lot more carbon in the ground," Schuur said. "Just by addressing the source of emissions that are from humans, we have this potential to just keep everything closer to its current state, frozen in permafrost, rather than going into the atmosphere."

The survey shows that by 2100, experts believe the amount of carbon released will be 1.7 to 5.2 times greater than previous models predict, under scenarios where Arctic temperatures rise 13.5 degrees Fahrenheit. Some predicted effects of global warming include sea level rise, loss of biodiversity as some organisms are unable to migrate as quickly as the climate shifts and more extreme weather events that could affect food supply and water resources.

"This new research shows that the unmanaged part of the biosphere has a major role in determining the future trajectory of climate change," said Stanford University biology professor Christopher Field, who was not involved in the study. "The implication is sobering. Whatever target we set for atmospheric CO2, this new research means we will need to work harder to reach it. But of course, limiting the amount of climate change also decreases the climate damage from permafrost melting."

When carbon is released from the ground as a result of thawing permafrost, there is no way of trapping the gases at the source, so action to slow its effect must be taken beforehand.

"If you think about fossil fuel and deforestation, those are things people are doing, so presumably if you had enough will, you could change your laws and adjust your society to slow some of that down," Schuur said. "But when carbon starts being emitted from the permafrost, you can't immediately say, 'OK, we've had enough of this, let's just stop doing it,' because it's a natural cycle emitting carbon whether you like it or not. Once we start pushing it, it's going to be releasing under its own dynamic."

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The above story is reprinted from materials provided by University of Florida. The original article was written by Danielle Torrent.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Edward A. G. Schuur, Benjamin Abbott. Climate change: High risk of permafrost thaw. Nature, 2011; 480 (7375): 32 DOI: 10.1038/480032a

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Abrupt permafrost thaw increases climate threat, experts say

ScienceDaily (Nov. 30, 2011) — As the Arctic warms, greenhouse gases will be released from thawing permafrost faster and at significantly higher levels than previous estimates, according to survey results from 41 international scientists published in the Nov. 30 issue of the journal Nature.

Permafrost thaw will release approximately the same amount of carbon as deforestation, say the authors, but the effect on climate will be 2.5 times bigger because emissions include methane, which has a greater effect on warming than carbon dioxide.

The survey, led by University of Florida researcher Edward Schuur and University of Alaska Fairbanks graduate student Benjamin Abbott, asked climate experts what percentage of the surface permafrost is likely to thaw, how much carbon will be released and how much of that carbon will be methane. The authors estimate that the amount of carbon released by 2100 will be 1.7 to 5.2 times larger than reported in recent modeling studies, which used a similar warming scenario.

"The larger estimate is due to the inclusion of processes missing from current models and new estimates of the amount of organic carbon stored deep in frozen soils," Abbott said. "There's more organic carbon in northern soils than there is in all living things combined; it's kind of mind boggling."

Northern soils hold around 1,700 billion gigatons of organic carbon, around four times more than all the carbon ever emitted by modern human activity and twice as much as is now in the atmosphere, according to the latest estimate. When permafrost thaws, organic material in the soil decomposes and releases gases such as methane and carbon dioxide.

"In most ecosystems organic matter is concentrated only in the top meter of soils, but when arctic soils freeze and thaw the carbon can work its way many meters down, said Abbott, who studies how carbon is released from collapsed landscapes called thermokarsts -- a process not accounted for in current models. Until recently that deep carbon was not included in soil inventories and it still is not accounted for in most climate models.

"We know about a lot of processes that will affect the fate of arctic carbon, but we don't yet know how to incorporate them into climate models," Abbott said. "We're hoping to identify some of those processes and help the models catch up."

Most large-scale models assume that permafrost warming depends on how much the air above the permafrost is warming. Missing from the models, say the authors, are processes such as the effects of abrupt thawing that can melt an ice wedge, result in collapsed ground and accelerate additional thawing.

"This survey is part of the scientific process, what we think is going to happen in the future, and how we come up with testable hypotheses for future research," Schurr said. "Our survey outlines the additional risk to society caused by thawing of the frozen North and the need to reduce fossil fuel use and deforestation."

By integrating data from previous models with expert predictions the authors hope to provide a frame of reference for scientists studying all aspects of climate change.

"Permafrost carbon release is not going to overshadow fossil fuel emissions as the main driver of climate change" said Schuur, "but it is an important amplifier of climate change."

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The above story is reprinted from materials provided by University of Alaska Fairbanks.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Edward A. G. Schuur, Benjamin Abbott. Climate change: High risk of permafrost thaw. Nature, 2011; 480 (7375): 32 DOI: 10.1038/480032a

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Governments must plan for migration in response to climate change, researchers say

ScienceDaily (Oct. 27, 2011) — Governments around the world must be prepared for mass migrations caused by rising global temperatures or face the possibility of calamitous results, say University of Florida scientists on a research team reporting in the Oct. 28 edition of Science.

If global temperatures increase by only a few of degrees by 2100, as predicted by the U.N. Intergovernmental Panel on Climate Change, people around the world will be forced to migrate. But transplanting populations from one location to another is a complicated proposition that has left millions of people impoverished in recent years. The researchers say that a word of caution is in order and that governments should take care to understand the ramifications of forced migration.

A consortium of 12 scientists from around the world, including two UF researchers, gathered last year at the Rockefeller Foundation's Bellagio Center to review 50 years of research related to population resettlement following natural disasters or the installation of infrastructure development projects such as dams and pipelines. The group determined that resettlement efforts in the past have left communities in ruin, and that policy makers need to use lessons from the past to protect people who are forced to relocate because of climate change.

"The effects of climate change are likely to be experienced by as many people as disasters," UF anthropologist Anthony Oliver-Smith said. "More people than ever may be moving in response to intense storms, increased flooding and drought that makes living untenable in their current location."

"Sometimes the problem is simply a lack of regard for the people ostensibly in the way of progress," said Oliver-Smith, an emeritus professor who has researched issues surrounding forced migration for more than 30 years. But resettlements frequently fail because the complexity of the task is underestimated. "Transplanting a population and its culture from one location to another is a complex process -- as complicated as brain surgery," he said.

"It's going to be a matter of planning ahead now," said Burt Singer, a courtesy faculty member at the UF Emerging Pathogens Institute who worked with the research group. He too has studied issues related to population resettlement for decades.

Singer said that regulatory efforts promoted by the International Finance Corporation, the corporate lending arm of the World Bank, are helping to ensure the well-being of resettled communities in some cases. But as more people are relocated -- especially very poor people with no resources -- financing resettlement operations in the wake of a changing climate could become a real challenge.

Planning and paying for resettlement is only part of the challenge, Oliver-Smith said. "You need informed, capable decision makers to carry out these plans," he said. A lack of training and information can derail the best-laid plans. He said the World Bank increasingly turns to anthropologists to help them evaluate projects and outcomes of resettlement.

"It is a moral imperative," Oliver-Smith said. Also, a simple cost-benefit analysis shows that doing resettlement poorly adds to costs in the future. Wasted resources and the costs of malnutrition, declining health, infant and elder mortality, and the destruction of families and social networks should be included in the total cost of a failed resettlement, he said.

Oliver-Smith said the cautionary tales of past failures yield valuable lessons for future policy makers, namely because they point out many of the potential pitfalls than can beset resettlement projects. But they also underscore the fact that there is a heavy price paid by resettled people, even in the best-case scenarios.

In the coming years, he said, many projects such as hydroelectric dams and biofuel plantations will be proposed in the name of climate change, but moving people to accommodate these projects may not be the simple solution that policy makers sometimes assume.

A clear-eyed review of the true costs of forced migration could alert governments to the complexities and risks of resettlement.

"If brain surgeons had the sort of success rate that we have had with resettling populations, very few people would opt for brain surgery," he said.

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The above story is reprinted from materials provided by University of Florida. The original article was written by Donna Hesterman.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

A. de Sherbinin, M. Castro, F. Gemenne, M. M. Cernea, S. Adamo, P. M. Fearnside, G. Krieger, S. Lahmani, A. Oliver-Smith, A. Pankhurst, T. Scudder, B. Singer, Y. Tan, G. Wannier, P. Boncour, C. Ehrhart, G. Hugo, B. Pandey, and G. Shi. Preparing for Resettlement Associated with Climate Change. Science, 2011; 334 (6055): 456-457 DOI: 10.1126/science.1208821

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