Tropical forests are seen as weighty allies in the fight against climate change, especially due to their large capacity to sequester carbon. However, their soils can release large quantities of carbon dioxide (CO2) as they become increasingly warm.
The warning comes from a group of scientists in an article published in the journal Nature Communications, in which they reveal the results of measurements taken in tropical soils in northeastern Puerto Rico.
According to the investigation, these soils may emit between 42% and 204% more CO2 at higher temperatures, defining subterranean ecosystems as a fundamental part of the global climate crisis.
“This research shows that, as the planet warms, tropical soils begin to amplify that warming,” notes Christine O’Connell, a biologist at Chapman University (United States) and co-author of the study.
If this phenomenon is happening in other regions of the Earth, scientists warn that we may be drastically underestimating the losses of carbon trapped in tropical forests and their contribution to the acceleration of climate change. And they remind that soils contain more carbon than the atmosphere and all terrestrial plants combined, so the loss of this carbon could intensify warming to a global level.
However, the researchers clarify that the carbon emissions from hotter tropical soils are not caused by the plants themselves, but by the microorganisms that inhabit them. Warmer soils can lead to a proliferation of microorganisms whose metabolisms, or “respiration”, release carbon, so more microorganisms can mean higher emissions.
For this team, understanding how tropical soil respiration changes on an increasingly warm planet is “fundamental” for obtaining global models that reflect more accurately the role of tropical ecosystems in climate change and to forecast long-term trends.
