When ground is disturbed in the course of planting trees, more carbon dioxide is released into the atmosphere by rotting organic matter in the soil than the new trees will absorb in ten years. Owners of large tracts of private land are usually unwilling to plant trees unless they are given a financial incentive for doing so. Many climate researchers believe that global warming is such an urgent problem that carbon dioxide emissions should be substantially reduced in less than ten years. Gases other than carbon dioxide contribute to global warming, and trees do not absorb any of these other gases.
Environment minister: Because of our concern about global warming, this country has committed itself to reducing its emissions of carbon dioxide substantially over the next ten years. Since trees absorb carbon dioxide, planting large numbers of trees will help us fulfill our commitment.
Which one of the following, if true, would most weaken the environment minister's argument?