How Trees Might Not Be Green in Carbon Offsetting Debate

It may have become the penance of choice for the environmentally conscious individual, but planting trees to offset carbon emissions could contribute to global warming if they are planted outside the tropics, scientists believe.They argue that most forests do not have any overall effect on global temperature but, by the end of the century, forests in the mid and high latitudes could make their parts of the world more than 3C warmer than would have occurred if the trees did not exist.