I recently returned from Costa Rica on a mission to work towards achieving CCB certification for the Pax Natura Project. The science involved in calculating how much carbon is sequestered in a tropical rainforest is amazing. Quite alluring actually.
There is nothing like it. Walking around with oodles of foresters who are measuring the circumference of tree trunks, inventorying the range of tree species and analyzing what is compacted to make the floor of the forest.
It's not guesswork, I can tell you that.
More later on the adventures of capturing carbon in the rain forests of Costa Rica.