Ill-conceived Forest Planting Could Worsen Global Warming
The interplay between forests and the atmosphere is complex and largely unknown. The conventional wisdom is that planting trees is a laudable response to climate change, but it is not so simple. A new study indicates trees planted in temperate areas actually raise temperatures by aborbing more heat - while trees in tropical areas transpire this heat more effectively thus leading to more cooling. These impacts may outweigh whatever benefits in terms of reduced warming result from carbon capture.
There is a whole array of unknowns regarding the interplay between forests and climate. Those with a vested interest in tree planting for alleged climate benefits must take heed or risk being label as charlatans. Other issues include whether replacing ancient forests with plantations may lead to more lost carbon storage than is gained by growing forests, and the possibility that if global warming continues apace forests - planted and otherwise - may suffer tremendous dieback and carbon release.
The lesson here is that given current knowledge humanity is well advised to focus upon reducing emissions from the burning of fossil fuels, energy efficiency and keeping existing carbon stored in intact ancient forests. Planting trees - particulary in monocultures outside of their natural ranges - should not be embraced as a climate change remedy at this point. By all means restoring of native forests where they traditionally occurred is another matter and should be pursued aggressively.
7/12/2005 -- Study: Forests could worsen global warming
A study by the Carnegie Institution and U.S. government scientists says planting trees to absorb carbon dioxide may worsen global warming... the researchers found that while tropical forests help keep Earth cool by evaporating a great deal of water, northern forests tend to warm the Earth because they absorb sunlight without losing much moisture. In one computer simulation, the scientists covered much of the northern hemisphere with forests and saw a jump in surface air temperature of more than 6 degrees Fahrenheit.
