Carbon Contributions of Different Regions Figure 3 illustrates the problem of omitting countries from the Berlin Mandate. Over the next century the share of responsibility for emissions will be very different from what it was in the past. The United States and other OECD countries will be responsible for only about 25 percent of cumulative emissions over the next century, and the United States alone for only about 10 percent. Unless the developing countries participate, it would be impossible to hold global emissions to current levels even if the OECD countries were removed from the picture entirely. Such a policy would be just acceptable, as an economic proposition, for the world as a whole.
Nonparticipating countries get a free ride-they receive benefits but bear none of the costs.
This is the classic public goods problem, in which it is impossible to exclude countries from the benefits of the policy change. The policies that appear to have economic benefits are fail-safe policies that can achieve emission reductions at no cost, and investing in science and in development of technologies that will reduce future costs. In assessing policy options, specific policies and measures must be evaluated, not general goals, since no goal can be assessed without specifying the policies likely to be used to achieve it.