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...