How to Avoid a Climate Disaster: The Solutions We Have and the Breakthroughs We Need

by Bill Gates

How long will the tree survive? If it burns down, all the carbon dioxide it was storing will be released into the atmosphere. What would’ve happened if you hadn’t planted that tree? If a tree would’ve grown there naturally, you haven’t added any extra carbon absorption. In what part of the world will you plant the tree? On balance, trees in snowy areas cause more warming than cooling, because they’re darker than the snow and ice beneath them and dark things absorb more heat than light things do. On the other hand, trees in tropical forests cause more cooling than warming, because they release a lot of moisture, which becomes clouds, which reflect sunlight. Trees in the midlatitudes—between the tropics and the polar circles—are more or less a wash. Was anything else growing in that spot? If, for example, you eliminate a soybean farm and replace it with a forest, you’ve reduced the total amount of soybeans available, which will drive up their price, making it more likely that someone will cut down trees somewhere else to grow soybeans. This will offset at least some of the good you do by planting your trees.