Decision-maker optimism and lack of criteria for decisions on appropriate responses to climate change are generally greater obstacle to initiating action that scientific uncertainty. Yet it is often discussion of scientific uncertainty that can have the most paralyzing effect on decision makers. This may be due to the failure of the scientific community to adequately formulate its advice in such terms of risk management which is a more familiar concept to policy experts than that of uncertainty.
Free-rider countries, who agree or opt out of to international treaties and then act in their own self-interest, is a major obstacle to international action on reducing the greenhouse effect. Just as in the case of local commons, there seem to be two solutions: to privatize the issue and leave it to competition between sovereign states (that is, war), or to centralize it and enforce obedience (that is, world government). But work on international environmental regimes to control such things as acid rain, oil pollution, and overfishing suggest that a middle way exists. Trade sanctions, blackmail, bribes, and even shame can be used between sovereign governments to create incentives for cooperation as long as violations can be easily detected.