WEIGHING FUNCTIONS FOR OZONE DEPLETION AND GREENHOUSE-GAS EFFECTS ON CLIMATE

Weighing functions are extremely useful tools for evaluating the relat ive effects of gases affecting global atmospheric ozone and climate. I n particular, the concepts of Ozone Depletion Potentials (ODPs) and Gl obal Warming Potentials (GWPs) are extensively used in policy consider ation and scientific studies of the ozone and climate issues. ODPs pro vide a relative measure of the expected cumulative impact on stratosph eric ozone from trace gas emissions, and are being used to examine the relative effects on ozone from CFCs, halons and other halocarbons cur rently being used and to evaluate the potential effects of possible re placement compounds. GWPs provide a means for comparing the relative e ffects on climate expected from various greenhouse gases. This chapter examines these weighing functions and other indices being used in eva luating concerns about global ozone and climate, discusses the science underlying these indices, and presents the current state-of-the-art f or numerical indices and their uncertainties.