The Antarctic Ozone Hole: A Unique Example of the Science and Policy Interface

Abstract

The discovery of an unexpected large depletion of the Antarctic ozone layer in the 1980s attracted the attention of scientists, policymakers, and the public. The phenomenon quickly became known as the “ozone hole.” Observations established that the ozone losses were driven primarily by humanmade compounds, chlorofluorocarbons and bromocarbons, whose chemistry is particularly enhanced for ozone loss under the extreme cold conditions of the Antarctic. Systematic longterm data of Antarctic total ozone date back to the 1950s at several international stations, and these key records owe their existence to the International Geophysical Year in 1957–1958 as well as to the Antarctic Treaty System. Although ozone depletion is greatest in the Antarctic, significant depletion has also been observed in the Arctic and at midlatitudes in both hemispheres. Ozone depletion enhances the ultraviolet light at the planet surface and thereby can damage ecosystems and some crops as well as increasing the incidence of human eye cataracts and skin cancer. These concerns led policymakers to agree to the Montreal Protocol on Substances that Deplete the Ozone Layer (Montreal Protocol) in 1987, and progressive advances in understanding the Antarctic ozone hole were important for the considerations by policy over the next 10 years that ultimately led to controls that have essentially phased out the production of chlorofluorocarbons and bromocarbons. Chlorofluorocarbons not only deplete ozone, but they are also greenhouse gases that contribute to climate change. It is not widely appreciated that the phaseout of the chlorofluorocarbons under the Montreal Protocol has probably contributed about five times more to mitigation of climate change than has occurred due to the Kyoto Protocol to the United Nations Framework Convention on Climate Change (Kyoto Protocol) to date. Thus, the Antarctic ozone hole and the subsequent scientific understanding and policy process have played key roles not only for ozone protection but also for climate protection.