Field experiments in the Smithsonian's Global Change Research Wetlands are helping scientists understand carbon storage in coastal habitats.
Image Credit: Genevieve Noyce
Your local wetland could be sending over 500 metric tons of methane into the atmosphere every year, per square mile. Or virtually none. It’s a bit of a mystery—one that’s been troubling climate scientists for decades. But a new report published this week is helping nail down which wetlands are more likely to be methane bombs.
Methane is one of the most powerful greenhouse gases on the planet. In a single century, it can warm Earth up to 45 times faster than the same amount of carbon dioxide. And wetlands are one of the planet’s biggest natural sources of it. At the same time, societies rely on wetlands for many things, including fighting climate change by trapping carbon dioxide. It’s estimated coastal wetlands can bury more carbon per unit area than even forests.
But the frequent methane leaks have proven problematic. And they’ve made it hard to pin down how much carbon wetlands can actually store as the world tries to keep global warming below a 1.5° Celsius (or 2.7° Fahrenheit) increase.
“We have a lot of information on the processes that create methane in tidal wetlands,” said Jim Holmquist, a wetland ecologist at the Smithsonian Environmental Research Center (SERC). “However, it is all limited to individual sites, studies and points in time. Putting all of these individual studies together helps us understand the major determinants of methane emissions….[A]nd it will help us prioritize tidal wetland restorations that lower methane emissions.”
Holmquist co-authored the new report along with University of Maryland soil scientist Brian Needelman and other members of the Coastal Carbon Network—a global community of scientists dedicated to understanding “blue carbon,” the carbon stored in wetlands and other coastal ecosystems around the world. The report was published Sept. 5 in the journal Global Change Biology.
