Ozone depletion and climate change
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Ozone depletion and climate change, or Ozone hole global warming in more popular terms, are environmental challenges whose connections have been explored and which have been compared and contrasted, for example in terms of global regulation, in various studies and books.
There is widespread scientific interest in better regulation of climate change, ozone depletion and air pollution, as in general the human relationship with the biosphere is deemed of major historiographical and political significance.[1] Already by 1994 the legal debates about respective regulation regimes on climate change, ozone depletion and air pollution were being dubbed "monumental" and a combined synopsis provided.[2]
There are some parallels between atmospheric chemistry and anthropogenic emissions in the discussions which have taken place and the regulatory attempts which have been made. Most important is that the gases causing both problems have long lifetimes after emission to the atmosphere, thus causing problems that are difficult to reverse. However, the Vienna Convention for the Protection of the Ozone Layer and the Montreal Protocol that amended it are seen as success stories, while the Kyoto Protocol on anthropogenic climate change has largely failed. Currently, efforts are being undertaken to assess the reasons and to use synergies, for example with regard to data reporting and policy design and further exchanging of information.[3] While the general public tends to see global warming as a subset of ozone depletion, in fact ozone and chemicals such as chlorofluorocarbons (CFCs) and other halocarbons, which are held responsible for ozone depletion, are important greenhouse gases. Furthermore, natural levels of ozone in both the stratosphere and troposphere have a warming effect.[citation needed]
There are various ways in which ozone depletion and climate change are interconnected, but ozone depletion is not a primary cause of climate change.
The Earth's atmospheric ozone has two effects on the Earth's temperature balance. Firstly, it absorbs solar ultraviolet radiation, leading to the heating of the stratosphere. Secondly, it also traps heat in the troposphere by absorbing infrared radiation emitted by the Earth's surface. Consequently, the impact of changes in ozone concentrations on climate depends on the altitude at which these changes occur. Human-produced chlorine- and bromine-containing gases, which cause major ozone losses in the lower stratosphere, have a cooling effect on the Earth's surface. In contrast, ozone increases in the troposphere caused by surface-pollution gases, contribute to the "greenhouse" effect and have a warming effect on the Earth's surface.