I believe that what we know now about global warming justifies imposition of a modest tax on carbon emissions by the U.S. and other developed nations. This is a first step toward assuring that future generations will not find the concentration of atmospheric gases increased so much that it cannot be practically reversed before changes in the Earth’s climate cause calamitous damage. [...] The U.S. should propose a small carbon tax as an alternative to the current national emission targets on the table for Kyoto. It is a first step that is more consistent with the state of scientific knowledge and the extent of international consensus; and it is a first step that is more likely to be politically acceptable in the U.S. today.