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The effect forests have is not understood well enough yet.

See e.g.

Lawrence Livermore National Laboratory: Trees to offset the carbon footprint? (April 10, 2007)

How effective are new trees in offsetting the carbon footprint? A new study suggests that the location of the new trees is an important factor when considering such carbon offset projects. Planting and preserving forests in the tropics is more likely to slow down global warming.

But the study concludes that planting new trees in certain parts of the planet may actually warm the Earth.


Forests affect climate in three different ways: they absorb the greenhouse gas - carbon dioxide - from the atmosphere and help keep the planet cool; they evaporate water to the atmosphere and increase cloudiness, which also helps keep the planet cool; and they are dark and absorb sunlight (the albedo effect), warming the Earth. Previous climate change mitigation strategies that promote planting trees have taken only the first effect into account.

"Our study shows that only tropical rainforests are strongly beneficial in helping slow down global warming," Bala said. "It is a win-win situation in the tropics because trees in the tropics, in addition to absorbing carbon dioxide, promote convective clouds that help to cool the planet. In other locations, the warming from the albedo effect either cancels or exceeds the net cooling from the other two effects."

by nanne (zwaerdenmaecker@gmail.com) on Thu Jan 3rd, 2008 at 06:46:15 AM EST
I think the study you mention does seem, somewhat, to agree with the research published in Nature. What those researchers were looking at were the affects a warmer environment has on boreal forests.

While not part of their study, the tropical rainforests do seem to be key in slowing down global warming.

I wonder though, if by the time we fully understand -- as in science has reached a consensus -- the effect forests it will be too late to best utilize the knowledge?

by Magnifico on Thu Jan 3rd, 2008 at 06:51:21 AM EST
[ Parent ]
The studies seem largely congruent as to the effect (a slower-growing boreal forest will still have largely the same albedo effect, I'd reckon).

Forests are largely a political distraction today, from taking the necessary measures to reduce climate pollution. It's good to have them off the table for the purpose of pushing the point that the solution is to stop polluting.

So, the best solution is to do something else, and grow forests for all the good reasons there are for growing forests outside of the climate change issue.

Tropical forests are the exception to this. We still haven't succeeded in stopping their reduction, even though protecting the rainforest is something we got concerned about a long time ago, independent of the climate change issue. It is important to make the local community responsible for nature protection. I'm worried that a structure for transferring funds for nature protection to countries in the tropics will ignore that.

by nanne (zwaerdenmaecker@gmail.com) on Thu Jan 3rd, 2008 at 07:38:47 AM EST
[ Parent ]


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