Deforestation causes global warming. Trees absorb CO2 and use it to grow. But when the trees died or been cut. CO2 will be released again. For this reason, deforestation has caused more damage to 2 times. Because different types of greenhouse effect has been released. At the same time. And the number of trees absorb CO2 is reduced. 30% increase in CO2 in the atmosphere 150 years ago, is expected to come from deforestation.