Research Validates Value of Wetlands as Buffers to Climate Change
Study by FGCU professor could alter ecological management
FORT MYERS, Fla. -- New research by a Florida Gulf Coast University eminent scholar proves that natural and manmade wetlands have a potential to mitigate climate change that far outweighs the negative effects of a greenhouse gas they emit.
Dr. William J. Mitsch, a prize-winning wetland scientist with an international reputation in ecological engineering and wetland ecology, conducted studies at wetlands around the world to measure carbon dioxide accumulated from the atmosphere and stored in the soil - a natural process known as carbon sequestration. Scientists compared the data to levels of methane gas naturally released by these "carbon sinks" and found that sequestration more than offsets the detrimental emissions even when the emissions are given a much higher weight toward global warming than the carbon dioxide sequestered.
"We have shown that wetlands are much more significant in accumulating carbon than has ever been published before," said Mitsch, who holds the Juliet C. Sproul Chair for Southwest Florida Habitat Restoration and Management at FGCU and is director of its Everglades Wetland Research Park in Naples. "We want people to recognize that wetlands are gigantic carbon sinks. If there is less carbon dioxide in the atmosphere, there will be less global warming and climate change."
Mitsch's findings, published in the journal Landscape Ecology (Springer Science+Business Media), could have far-reaching ramifications in the study, creation, restoration and management of wetlands. The paper is coauthored by seven other scientists from the United States, Denmark and Estonia.
Greenhouse-gas emission has long been considered by some scientists as a serious roadblock to restoring wetlands and constructing new ones in spite of their environmental benefits. It's estimated that wetlands release 20 to 25 percent of current global methane emissions, but the gas eventually breaks down in the atmosphere.
"It is short-sighted to suggest that wetlands should not be created or restored because of greenhouse-gas emissions," Mitsch writes in his paper, "Wetlands, carbon, and climate change." "If we consider the savings that wetlands give us from fossil-fuel consumption for the ecosystem services of water-quality improvement, flood mitigation and coastal and storm protection, their service as carbon sinks is even more impressive."
Dr. Robert Costanza, a senior fellow at the National Council on Science and the Environment, a scholar at the Australian National University in Canberra and founder of the sustainability journal Solutions, says Mitsch's study refutes commonly held conceptions.
"Understanding the role of wetlands in regulating greenhouse gases is extremely important," Costanza says. "The results will affect how we manage wetlands worldwide."
Dr. Blanca Bernal, a post-doctoral researcher at Everglades Wetland Research Park contributed to the study and paper. She believes it is the first published account that compares carbon accumulation rates and methane emission rates using the same methodology in a range of freshwater wetlands around the world. Measurements were taken at seven locations in Ohio, Costa Rica and Botswana and modeled with 14 other wetland studies by others.
"Taking into account carbon inputs and outputs to the system, the wetlands are actually functioning as net carbon sinks," Bernal says. "They have a positive effect in abating greenhouse-gas emissions, which means under the right conditions they can be used as a tool to mitigate climate change. Wetlands are not the key to fix years of unsustainable carbon emissions, but they can help significantly."
Public awareness of the importance of carbon dioxide sinks has spread since passage of the Kyoto Protocol, part of an international environmental treaty that promotes their use as a form of carbon offset and encourages greenhouse-gas reduction worldwide. Some member countries seek to buy or trade emissions rights in carbon-emission markets, creating an additional economic value to wetlands.
Carbon in the Earth's atmosphere comes partly from burning fossil fuels in cars and factories. Oceans, which comprise about 70 percent of the planet, are the biggest collectors of carbon. Wetlands, which absorb about 14 percent of atmospheric carbon, make up 5 to 8 percent of terrestrial Earth but are dwindling due to development.
"I think we have found the lost carbon sink," says Mitsch, the co-author of "Wetlands," widely considered the definitive textbook on the subject. "Tropical wetlands are where it's happening. The temperate zone would be big for sequestration, but we've drained all the wetlands there. Florida could be a hot spot for carbon sinks."
Mitsch joined FGCU in October after 27 years at The Ohio State University in Columbus, where he was Distinguished Professor of Environment, Natural Resources and Ecological Engineering. The co-winner of the 2004 Stockholm Water Prize for lifetime achievements in the management and conservation of lakes and wetlands, he oversees research at the Everglades Wetland Research Park at the Naples Botanical Garden.
For more information, contact Mitsch at (614) 946-6715 or firstname.lastname@example.org. A PDF of his paper can be downloaded here: http://link.springer.com/article/10.1007/s10980-012-9758-8.