Carbon sequestration by terrestrial ecosystems has made it possible to offset almost 30% of anthropogenic emissions. However, the distribution of this carbon between the different reservoirs – living or dead biomass, organic carbon in the soil and sediments – remains unknown.
Analysing global data on terrestrial carbon pools, the researchers found that while ≈ 35 ± 14 gigatonnes of additional carbon (GtC) were sequestered in terrestrial ecosystems between 1992-2019, living biomass only gained ≈ 2 ± 7 GtC.
This balance contradicts the models used for the global carbon balance, in which carbon sequestration is mainly due to living biomass. This discrepancy can be explained by the failure of many models to take into account key processes.
In most cases, carbon is sequestered in the form of inert organic matter and is therefore more persistent than previously thought, with a substantial fraction linked to human activities: sediments accumulated in dams, harvested wood, waste – particularly of plant origin – in landfill sites, and so on.
LSCE contact: Philippe Ciais
References
Recent gains in global terrestrial carbon stocks are mostly stored in non-living pools, Science
https://www.science.org/doi/10.1126/science.adk1637