The greenhouse effect is created when heat from the sun enters the atmosphere and is prevented from radiating back into space by air-polluting gases. The buildup of about 40 heat-trapping gases is created mostly by human activities. Heat buildup threatens to raise global temperatures to levels unprecedented in human history. About half of the greenhouse effect is caused by CO2. Trees act as a carbon sink by removing the carbon from CO2 and storing it as cellulose in the trunk while releasing the oxygen back into the air.
Trees also reduce the greenhouse effect by shading our homes and office buildings.
This reduces air conditioning needs up to 30 percent, thereby reducing the amount of fossil fuels burned to produce electricity. This combination of CO2 removal from the atmosphere, carbon storage in wood, and the cooling effect makes trees a very efficient tool in fighting the greenhouse effect. Trees create organic matter on the soil surface from their leaf litter. Their roots increase soil permeability. Reduced surface runoff of water from storms .