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Argument: Reforestation can increase Earth's Albedo and global warming
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Supporting quotations
Umbra Fisk. "The Problem of the Root". Grist. 22 Jan 2007 - Planting gobs of new forests in temperate zones, it seems, will have a negligible or even negative effect on global warming in the long term. Tropical forests, on the other hand, will have a positive effect, the study said.
How is it true that trees could be bad for something?
Doubtless you are familiar with the concept that trees uptake carbon and have helped ameliorate our recent carbon loading of the atmosphere. Trees also evaporate water and contribute to cloudiness, keeping things a bit cooler. What swung these positive effects to the neutral or negative in the large-scale climate model was a third property of forests: albedo.
Who remembers this term from their climate reading? It means reflectivity, basically. It comes from the Latin word for white, and is similar to albino -- but not libido. Forests, all dark with leaves and stuff, have a low albedo. Shiny ice sheets have a high albedo. Remember one problem with the (predicted) end of summer ice in the Arctic is the permanent ice sheet's current role in reflecting sunlight and heat away from Earth. As the ice disappears, warming may increase rapidly when the high-albedo surface provided by miles and miles of whiteness is replaced by darker, lower-albedo ocean water.
Since forests don't tend to reflect heat, they hold a lot of warmth. When the study authors integrated albedo into their computer model, they found that replacing grasslands and other non-forested areas with forests in temperate zones (e.g., North America, Europe) would eventually lead to net warming of the Earth. In tropical areas (e.g., Brazil), forests exhale more water; scientists say this contribution to cloudiness will help cancel out the warming effect.
