Comment by Manuel_D
2 months ago
Man-made carbon emissions amount to over 40 billion metric tons annually, according to a quick Google search. Worldwide terrestrial plant carbon exchange amounts to less than 2.5% of the CO2 humans release, if plants take in 1 billion tons per year.
From the perspective of averting climate change it is indeed very small.
The article linked by 8bitsrule says:
A team of scientists led by Cornell University, with support from the Department of Energy’s Oak Ridge National Laboratory, used new models and measurements to assess GPP from the land at 157 petagrams of carbon per year, up from an estimate of 120 petagrams established 40 years ago and currently used in most estimates of Earth’s carbon cycle.
Whether 157 billion tons or 120 billion tons, these numbers are large compared to anthropogenic releases. Of course most of this carbon is quickly cycled back out from land plants due to animals/bacteria/fungi consuming the biomass produced by land plants.