Comparing the Effects of Greenhouse Gas Emissions on Global Warming

This paper analyses the usefulness as a policy tool of a physical index of radiative forcing of a greenhouse gas, the Global Warming Potential (GWP), as proposed by the Intergovernmental Panel on Climate Change. It is shown that the economic opportunity costs of an increment in radiative forcing will vary over time, while the GWP implicitly sets these costs equal. The GWP can, therefore, play no role in policy making.