Soil and sediment store more CO2 than trees

A new study published on March 23 reveals that soil, river sediment, and dead vegetation store more carbon dioxide (CO2) than trees. This finding challenges previous beliefs about how the Earth captures carbon. The study shows that about one-third of human-released CO2 is absorbed by land-based carbon sinks, which include forests and oceans. These sinks play a vital role in reducing global warming by trapping heat. However, trees are facing threats from climate change, diseases, wildfires, and deforestation, which reduce their ability to absorb CO2. Researchers highlight the need to better understand how carbon is distributed between living plants and non-living materials, such as soil and decaying wood. This understanding is important because different ecosystems face various environmental threats and have different capacities to store carbon. The study, conducted by an international team, assessed changes in carbon storage from 1992 to 2019. It found that most of the CO2 accumulated during this time was in non-living organic matter. This suggests that terrestrial carbon storage may be more stable than previously thought. The results differ significantly from earlier studies, which estimated that living matter accounted for about 70% of carbon stored on land. In some regions, like parts of the Amazon, deforestation and climate change have led to a shift from carbon sinks to sources of CO2 emissions. The Arctic tundra, too, is now emitting CO2 as it warms and faces wildfires.