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Ozone layer

The greenhouse gases:

The following table shows the other ‘greenhouse’ gases. They have contributed to the ‘enhanced’ greenhouse effect, through their impact on the ozone in the upper atmosphere. The impact of ozone itself is hard to quantify and scientifically uncertain. Chlorofluorocarbons (CFCs) are the strongest greenhouse gas per molecule. However, their low concentrations in the atmosphere mean that they are less relevant to the production of the enhanced greenhouse effect.

Holes in the ozone layer

CFCs also affect the ozone layer in the upper atmosphere that protects temperatures on Earth by blocking ultraviolet rays from the sun. There have been reports of enlarged holes in the ozone layer of the atmosphere over the North and South Poles. That, and a general decline in global stratospheric ozone levels, has caused many nations to cutback on their production and use of these chemicals. In 1987, the signing of the Montreal Protocol by forty-six nations established an immediate timetable for the global reduction of CFC production and use. As a result, the levels of CFC's in the atmosphere peaked in 1995 and have been falling have started to fall. The holes may even be starting to recover.

Gas Conc
Average time spent in atmosphere (years) Source Why it has increased




Car exhausts

More fossil fuels for transporrt




Expanders (foams)

More refrigerators etc. (Montreal Protocol has banned use of CFCs in developed countries.

The effects of climate change

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