The amount of carbon dioxide (CO2) in the atmosphere is partly controlled by how much the biosphere puts in and takes out. It’s estimated that the global terrestrial land sink (vegetation and soils) is currently removing a net 2.4 petagrams (2.4 billion tonnes) per year (based on data from 2000-2009).
The Amazon rainforest contains almost half of all carbon stored by terrestrial vegetation. As a result, even relatively small changes in the behaviour or distribution of Amazonian forests could have important consequences for the global carbon cycle.
Researchers in the School of Geography are coordinating the RAINFOR initiative, bringing together teams of scientists across the Amazon. The work of RAINFOR scientists indicates that tropical forests have experienced increased rates of mortality during the past few decades, but also increased biomass accumulation in mature forests. This increased biomass accumulation suggests that old-growth Amazonian forests were acting as a carbon sink during the 1980s and 1990s.
Scientists from the School of Geography also co-ordinate the AfriTRON initiative, bringing together scientists and plot inventory data across tropical Africa, including the Congo Basin, the world’s second largest expanse of tropical forest. The work of scientists within AfriTRON indicates that similarly to Amazonian forests, mature African tropical forests have increased in biomass over recent decades and have been acting as a carbon sink. New analyses of African forests have also shown how the structure of African, Amazonian and Asian forests differs, as does their function with potentially important implications.