Abstract
The rate of natural sequestration of CO2 from the atmosphere by the terrestrial biosphere peaked in 2008. Atmospheric concentrations will rise more rapidly than previously, in proportion to annual CO2 emissions, as natural sequestration is now declining by 0.25% per year. The current atmospheric increment of +2.5ppm CO2 per year would have been +1.9ppm CO2, if the biosphere had maintained its 1960s growth rate. This effect will accelerate climate change and emphasises the close connection between the climate and nature emergencies. Effort is urgently required to rebuild global biodiversity and to recover its ecosystem services, including natural sequestration.
https://www.nature.com/articles/s41467-018-05668-6
This paper zooms in on the Amazon forest (used to be the hugest CO2 sequestration area). Every drought year signals the start of a multiple year long stretch where there is a loss of Carbon uptake in the forest. The trees are damaged, weakened and dying from each round of drought.
These droughts are happening on a 5-6 year cycle, and the damage to Carbon absorption lasts from 3-5 years each time.
If I’m doing the math correctly, the annual contribution to global CO2 from the forest was around 1/8 of a year’s human fossil fuel contributions…