Global Warming Is Accelerating CO2 and Methane Emissions

An international team of scientists has found that organic matter decomposes more rapidly in the planet’s warmest and wettest areas, such as tropical areas and river ecosystems, which will lead to higher CO2 and methane emissions into the atmosphere. The finding, published today in Science Advances, is important because it confirms that global warming could aggravate that process by generating a natural increase in greenhouse gas emissions from specific zones of the planet.

The conclusions of the study are based on an experiment coordinated by Scott D. Tiegs, a professor at the Oakland University in Michigan, in the US, and carried out with the help of 150 researchers from around the world. For the study, the researchers carried out an identical bioassay, based on a method that is simple enough to evaluate the level of degradation of organic matter with small strips of cotton.

This simple test allowed scientists to assess the level of decomposition of organic matter and to estimate the rates of carbon processing in river ecosystems around the world. “The experiment has allowed us to have a global image of organic carbon around the world,” the researchers pointed out.

Global Warming Is Accelerating CO2 and Methane Emissions

The extra CO2 comes from the organic matter generated in forests, such as branches and leaves that fall from trees. A part of it is decomposed and stored in forest soils but the majority of these remains are transported by rain to rivers and streams, and from there, to the oceans.

Understanding these processes, however, is crucial because the degradation of this organic matter generates emissions of greenhouse gases such as carbon dioxide or methane. The results of the new study suggest that climatic factors such as temperature and precipitation are “important variables” that accelerate carbon decomposition. Also, global warming is speeding up this process, too.

“We have seen that temperature and humidity are greatly affected by global warming, and that is important because greater decomposition of organic matter in inland river ecosystems means more CO2 emissions into the atmosphere” one of the researchers explained.