Saltwater and freshwater marsh plants have been shrinking due to human activity such as draining for agriculture and logging. Wetlands amount to just 1% of the Earth’s surface, yet they are responsible for absorbing over 20% of the carbon dioxide that causes global warming.
The good news is that it is not too late to reverse this process, according to a paper published in the Science journal. The study’s authors argue that the key to success is using restoration practices on a large scale that simulate natural processes and improve the restored wetlands’ capacity to store CO2.
“About 1% of the world’s wetlands are being lost each year to pollution or marsh draining,” said Brian R. Silliman of Duke University, who co-authored the study. This leads to the release of huge amounts of CO2 from the wetlands’ soils, the scientist explained.
“The good news is, we now know how to restore these wetlands at a scale that was never before possible,” he added.
Silman explained that marsh plants are effective in storing carbon because they form as a result of vegetation that grows close together. The mats of stems and roots both above and below the ground trap nutrient-rich debris thus preventing erosion or drying out. In turn, the plants grow better and the soil layer builds up, storing much more CO2.
The process is a bit different when it comes to raised peat pots, the scientist explained. The layers of living peat moss hold large amounts of rainwater, which support its own growth and preserve a much thicker layer of peat moss beneath it that stays permanently underwater.
This low layer of moss does not allow the release of CO2 back into ambient air. Mr Silman noted that successful restorations must mimic these processes.
Scientists from the Netherlands, Germany and the U.S. also participated in the new study. They discovered that, when looking at the amount of carbon dioxide stored per square meter, wetlands are five times more effective than forests and 500 times more effective than oceans.