In my high school biology class we were studying biogeochemical cycles, including the carbon cycle. One paragraph detailed how humans, by burning fossil fuels, are putting more carbon dioxide into the air than is being removed, causing global warming, etc. According to my textbook, transportation accounts for most of the carbon dioxide being added to the air since our cars use petroleum-based fuels. The book also notes that trees and other green plants remove carbon dioxide from the atmosphere. How many houseplants, acres of grass, and trees should I have if I want to take as much carbon dioxide out of the atmosphere as I’m putting in? –John L. White
Best of Chicago voting is live now. Vote for your favorites »
Scoffers may say: This kid’s on crack. But if he is, so is the United Nations. A controversial trees-for-pollution trading scheme, hereafter referred to as “T4P” (houseplants and grasses are too short-lived to be useful), was inserted into the UN’s 1997 Kyoto Protocol on climate change. The idea: Polluting countries can earn “forest credits” by planting or conserving trees to remove from the atmosphere the carbon dioxide their cars and factories pump in. Under Bush the U.S. has disavowed the Kyoto agreement, but even so a brisk business in “certified tradable offsets” and such has sprung up–meaning, among other things, that first world polluters can pay third world nations to set aside forests as “carbon sinks.”
(2) It won’t work. This argument is more telling. Unlike carbon buried in coal, oil, or sedimentary rock, carbon in trees is unstable–one giant forest fire and much of it is released back into the atmosphere, leaving you back where you started, and even without a fire carbon is eventually liberated by decay. There are yawning gaps in our knowledge of global carbon exchange at the most basic level: Each year humans release about 6.7 billion tons of carbon into the atmosphere, and natural processes take about 3.5 billion tons out. We know the oceans absorb roughly 2 billion tons. The remaining 1.5 billion…well, we’re not quite sure where it goes. Evidence suggests there are large natural carbon sinks on land in the middle latitudes of both hemispheres, as well as natural carbon sources in the tropics. But we’ve still got a lot to learn. Even in well-understood processes such as plant respiration, many variables are involved–if the climate became permanently warmer, for instance, many assumptions about how trees process carbon dioxide would go out the window.
Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.
