This month, the journal Nature Geoscience published a study calculating that deforestation is responsible for about 15% of global carbon emissions, down from earlier estimates of 20% or more. Most of the world's deforestation is concentrated in a few tropical nations, like Brazil and Indonesia where trees are disappearing fast — when these trees die or are burned, they release into the atmosphere all the carbon they've sucked up while they were alive. According to the Nature Geoscience study, the problem of deforestation is becoming a lot less dire than previously thought.