Some CO2 gets trapped on land

I suppose it is general knowledge that only half of fossil C burn stays in the atmosphere. The other half is (about) equally split between land and ocean uptake.

For the former, it has been unclear where this is happening. Now it is a bit clearer.

Yi Y. Liu et al (in press) Recent reversal in loss of global terrestrial biomass
Nature Climate Change
DOI: 10.1038/NCLIMATE2581

I show their Fig. 1C. How this land uptake varies across vegetation types. These are changes (teragrams per year) from 1993-2012. ABC - aboveground carbon.

The tropical 'carbon sink' is decreasing because of clearing. Undisturbed forests there are mostly doing well (there are some drought issues). High latitude forests are bulking up.

We should have little doubt that if tropical forests were spared, they could sequester more carbon. But this intrudes into 'policy'.

 

I hope you would not take ill a suggestion to read the paper, Or Pan et al. 2011 from which it drew heavily. You may be asking how much of the (about) 1.8 petagrams of carbon per year is sequestered in each broad vegetation type. The answer is not quite as clear as we'd like. High-latitude forests are certainly important. And by this new work, becoming more so. Perhaps it seems odd to say so, but the rates of change appear easier to figure out than the absolutes.

One aspect that could be surprising is that we don't have a really accurate picture of how much biomass is where. Less so, carbon that is present in soils and dead plant material. Satellites and Asner's LIDAR are really advancing the 'visible' parts. Boots on the ground, measuring things, perhaps less so. The (UN) FAO asks every country to self-report on their forests. I''d rather not be drawn into a discussion about the validity of such estimates

The OCO-2 satellite is supposed to help a lot.