This brochure describes the role of ozone in the stratosphere, and the effect it has on ultraviolet light, as well as how the Montreal Protocol and subsequent laws have affected ozone-depleting pollutants in the atmosphere.
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This brochure describes the role of ozone in the stratosphere, and the effect it has on ultraviolet light, as well as how the Montreal Protocol and subsequent laws have affected ozone-depleting pollutants in the atmosphere.
This text is part of the following collection of related materials.
Environmental Policy Collection
The Environmental Policy Collection contains reports, policy documents, and media selected from local, statewide, national, and international organizations; government and private agencies; and scientific and research institutions. The collection also contains theses and dissertations relevant to environmental policy.
This Synthesis and Assessment Product (SAP 2.4) focuses on the Climate models. Depletion of the stratospheric ozone layer by human-produced ozone-depleting substances has been recognized as a global environmental issue for more than three decades, and the international effort to address the issue via the United Nations Montreal Protocol marked its 20-year anniversary in 2007. Scientific understanding underpinned the Protocol at its inception and ever since. As scientific knowledge advanced and evolved, the Protocol evolved through amendment and adjustment. Policy-relevant science has documented the rise, and now the beginning decline, of the atmospheric abundances of many ozone-depleting substances in response to actions taken by the nations of the world. Projections are for a return of ozone-depleting chemicals (compounds containing chlorine and bromine) to their "pre-ozone-depletion" (pre-1980) levels by the middle of this century for the midlatitudes; the polar regions are expected to follow suit within 20 years after that. Since the 1980s, global ozone sustained a depletion of about 5 percent in the midlatitudes of both the Northern Hemisphere and Southern Hemisphere, where most of the Earth's population resides; it is now showing signs of turning the corner towards increasing ozone. The large seasonal depletions in the polar regions are likely to continue over the next decade but are expected to subside over the next few decades.