International treaties in pursuit of common endeavors can be classified into two categories: those that set mutually agreed national objectives and leave each signatory to pursue them in their own way; and those that define mutually agreed actions. The proposed treaty on global climate change falls into the first category with respect to greenhouse gas emissions by the rich countries. Stabilization of atmospheric concentration of greenhouse gases requires eventual engagement of developing countries. The proposed treaty, based on historical emission levels, does not provide a foundation acceptable to them. Indeed, there is unlikely to be any generally acceptable principle for allocating emission rights, potentially worth trillions of dollars, among rich and poor countries. This probable impossibility suggests a successful attack on greenhouse gas emissions, necessarily international in scope, must be through mutually agreed actions, such as a nationally-collected emissions tax, rather than through national emission targets.