JOIN USMost of the carbon resulting from wildfires and fossil fuel combustion is rapidly released into the atmosphere as carbon dioxide. Researchers at the University of Zurich have now shown that the leftover residue, so-called black carbon, can age for millennia on land and in rivers en route to the ocean, and thus constitutes a major long-term reservoir of organic carbon. The study adds a major missing piece to the puzzle of understanding the global carbon cycle.
Due to its widespread occurrence and tendency to linger in the environment, black carbon may be one of the keys in predicting and mitigating global climate change. In wildfires, typically one-third of the burnt organic carbon is retained as black carbon residues rather than emitted as greenhouse gases. Initially, black carbon remains stored in the soil and in lakes and is then eroded from river banks and transported to the ocean. However, black carbon is not taken into account in global carbon budget warming simulations.