A short story from my backyard – Denmark.
Copenhagen Municipality has plans of CO2 compensating the air travel of their employees by planting trees. Great idea, right? Last year these flights emitted 442 tons of CO2. 153000 trees would be necessary to compensate these 442 tons. Copenhagen doesn’t have the money for that. They will only plant 215 trees.
This is a fine illustration of how bad the idea of CO2 compensation through forestry is. We shouldn’t compensate and continue; we should start emitting less CO2.
But let us play with the idea a bit: 153000 trees bind 442 tons of carbon each year. This number will decrease when the trees are closer to maturity, so it won’t last. We would need approx. 346 trees for every ton of carbon removed. This means that each tree will remove a little less than 3 Kg of carbon each year – but only in the childhood and youth of these trees.
Denmark emitted 53,703,000 tons of carbon in 2012, so if we planted a mere 18,5 billion trees we would compensate completely for our CO2 emmissions – at least until early maturity of the trees.
A standard Danish mixed forest remove about 1,000 tons of carbon for every square kilometre every year. The necessary area would be 53,730 square kilometer. The area of Denmark is 42933 square kilometer, which means that every square meter of Denmark would be needed + 25 %, to compensate completely.
But we should not just compensate: We must lower our emission, permanently. Afforestation can contribute, but is far from enough. The problem is that many, including Danish, companies are now shoveling in great profits from offering this service, and a lot of customers jump right in, to be able to pat their own shoulder: just pay off and you can continue to import and export, to fly on business class instead of using skype, eat one stake after the other etc.
We should change our behavior so that we emit less carbon, by about 3-4 % each year (source).
That doesn’t mean that we should not plant trees. There are many good reason to do that, among them is to contribute to lowering the CO2 strain on the atmosphere, and to increase biodiversity. But we should not use this as an excuse to not change our behavior significantly. Trees won’t continue to have a net uptake of CO2 after they have matured. So if we don’t change our behavior permanently we won’t reach the goal in the tour de COP race.