RE:How much have we accumulated ?My research shows that its a single mature twenty year old tree will both sequester around 3 tonnes of CO2 in its woody mass and also lock about 3 tonnes of CO2 into a cycle of growing leaves, dropping them and decomposition, so a total of 6 tonnes offset;
However, in the tropics, the energy turnover rate is much higher which means that tropical trees which grow twice as fast as temperate or boreal trees.
So the 6 tons of carbon offset becomes 12 tons per tree over its life time.
NPK already have 30,000 trees on their reforested farmland which over their life cycle should offset about 360,000 tons of carbon..
I have no idea as to how far along these trees are in their life cycle of 15 years but let's say for arguments sake that it's 5 years , then NPK has already accumulated over 100,000 tons of carbon credits .
Costs tend to be about $50 per ton.