Scientific Assessment of Ozone Depletion: 2002

Executive Summary

2002 Ozone Assessment Executive Summary cover
Executive Summary

The provisions of the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer include the requirement that the Parties to the Protocol base their future decisions on the current scientific, environmental, technical, and economic information that is assessed through panels drawn from the worldwide expert communities. To provide that input to the decision-making process, advances in understanding on these topics were assessed in 1989, 1991, 1994, and 1998. This information helped support discussions among the Parties that led to the subsequent Amendments and Adjustments of the 1987 Protocol. The 2002 Scientific Assessment summarized here is the fifth in that series.

Recent Major Findings and Current Scientific Understanding

Since the Scientific Assessment of Ozone Depletion: 1998, numerous laboratory investigations, atmospheric observations, and theoretical and modeling studies have produced new key findings and have strengthened overall understanding of the ozone layer and its effect on ultraviolet (UV) radiation. These advances are highlighted in the following summary of the current understanding of the impact of human activities and natural phenomena on the ozone layer and the coupling of the ozone layer and the climate system.

Changes in Ozone-Depleting Compounds

Changes in the Ozone Layer over the Poles and Globally

Changes in Ultraviolet Radiation

The Ozone Layer and Climate Change

Additional Scientific Evidence and Related Information

Halocarbon Abundances

Halocarbon Lifetimes

Methyl Bromide, Methyl Chloride, and Halons

Very Short-Lived Ozone-Depleting Compounds

Polar Ozone

ANTARCTIC
ARCTIC

Global Ozone

TOTAL COLUMN OZONE
VERTICAL OZONE DISTRIBUTION
OZONE-RELATED CONSTITUENTS
STRATOSPHERIC TEMPERATURE
ATTRIBUTION OF PAST CHANGES IN OZONE
FUTURE OZONE CHANGES

Ultraviolet Radiation

Implications for Policy Formulation

The results from over three decades of research have provided a progressively better understanding of the interaction of humankind and the ozone layer. New policy-relevant insights into the roles of ozone-depleting gases have been conveyed to decisionmakers through the international state-of-understanding assessment process. The research findings in the Scientific Assessment of Ozone Depletion: 2002 that are summarized above are direct current scientific input to governmental, industrial, and policy decisions associated with protection of the ozone layer.