If a tree falls

Umbra Fisk answers environmental questions every week at grist.org. I signed up to have them sent straight to my inbox. I thought this week's article was particularly interesting over some of the usual paper vs plastic bantering, and wanted to share the contents.

According to research, planting trees in certain locations on Earth can contribute to global warming rather than combatting it, which frightens me and probably a lot of you, due to the inherent counter-intuitiveness of the idea.

This is due to albedo (reflectivity, in this case of solar energy). Umbra explains it best:

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.