This document is part of the information upon which the Parties to the United Nations Montreal Protocol will base their future decisions regarding ozone-depleting substances, their alternatives, and protection of the ozone layer. It is the latest in a long series of scientific assessments that have informed the Parties and contains the policy-relevant major findings of the Assessment's five scientific chapters. Actions taken under the Montreal Protocol have led to decreases in the atmospheric abundance of controlled ozone-depleting substances (ODSs), and are enabling the return of the ozone layer toward 1980 levels. This comprehensive volume includes many tables, figures, and charts throughout; and the appendices include acronyms and abbreviations, listings of authors, contributors, and reviewers from around the world, and chemical formulas. Related products: NASA and the Environment: The Case of Ozone Depletion is available here: https://bookstore.gpo.gov/products/nasa-and-environment-case-ozone-depletion Code of Federal Regulations, Title 40, Protection of Environment, Pt. 96-99, Revised as of July 1, 2016 can be found here: https://bookstore.gpo.gov/products/code-federal-regulations-title-40-protection-environment-pt-96-99-revised-july-1-2016 Our Changing Atmosphere: Discoveries from EOS Aura (Booklet) -reduced list price while supplies last available here: https://bookstore.gpo.gov/products/our-changing-atmosphere-discoveries-eos-aura-booklet

The U.S. Climate Change Science Program is in the process of producing 21 draft assessments that investigate changes in the Earth's climate and related systems. These assessments are designed to inform decisionmakers about the scientific underpinnings of a range of environmental issues, such as stratospheric ozone. This National Research Council report reviews one of these assessments, Synthesis and Assessment Product (SAP) 2.4, Trends in Emissions of Ozone Depletion Substances, Ozone Layer Recovery, and Implications for Ultraviolet Radiation Exposure. This assessment is noted as being the first-ever attempt to look at the United States contribution to ozone-depleting substances and ozone recovery. This National Research Council book commends the assessment's authoring team for comprehensively covering the scientific basis of ozone and ozone-depleting substances, but recommends several ways that the assessment could be improved. Suggestions include clarifying the discussion on climate effects of ozone and revising the approach to estimating U.S. contributions to production, consumption, and emission of ozone-depleting substances. The assessment could also be improved by reorganizing and editing to accommodate intended audiences.

This groundbreaking study of environmental assessment “provides an essential examination of the factors that shape and dictate our climate policy” (Choice). Discerning Experts reexamines the assessments that many governments rely on to help guide environmental policy and action. Through their close look at reports involving acid rain, ozone depletion, and sea level rise, the authors explore how experts deliberate and decide on the scientific facts about problems like climate change. They also seek to understand how the scientists involved make the judgments they do, how the organization and management of assessment activities affects those judgments, and how expertise is identified and constructed. Discerning Experts uncovers factors that can generate systematic bias and error, and recommends how the process can be improved. As the first study of the internal workings of large environmental assessments, this book reveals their strengths and weaknesses, and explains what assessments can—and cannot—be expected to contribute to public policy and the common good.

For two decades, scientists have been warning that chlorofluorocarbons (CFCs) and halons (bromine-containing fluorocarbons) may deplete the stratospheric ozone shield that screens out some of the Sun's harmful ultraviolet rays and thus regulates the amounts which reach the Earth's surface. CFCs have been used as refrigerants, solvents, foam blowing agents, and outside the United States, as aerosol propellants; Halons are used primarily as fire-fighting agents. Increased radiation could result in an increase in skin cancers, suppression of the human immune system, and decreased productivity of terrestrial and aquatic organisms, including some commercially important crops. This book deals with implementation, policy issues and phase out of methyl bromide. In September 1987, 47 countries (including the United States) agreed to the Montreal Protocol on Substances that Deplete the Ozone Layer, which first required controls on the world's consumption of ozone depleting substances. Over 160 countries have signed on to the Protocol, whose phasedown schedule for developed countries was accelerated twice and completely phased out Halon production at the end of 1994 and CFC production at the end of 1995. The Protocol's coverage has also been extended to include hydrochlorofluorocarbons and other chlorine- and bromine-containing substances such as some solvents and methyl bromide, a widely used soil fumigant.