Good for the ozone layer, bad for the climate

Posted in June 2009

By 2050, the contribution of hydrofluorocarbons (HFCs) to global warming will be more than that of current global CO2 emissions from houses and office buildings. These HFCs, gases used in refrigerators and air conditioners, are substitutes for ozone-depleting gases, but they are also strong greenhouse gases. Their contribution to global warming is currently small, but can increase to between 9 and 19% of the total CO2 contribution, by 2050. This is the conclusion of the article 'The large contribution of projected HFC emissions to future climate forcing’, appearing today in Proceedings of the National Academy of Sciences. Lead author is Guus Velders of the Netherlands Environmental Assessment Agency.

Demand for HFCs increases, especially in Asia
In the coming decades, the demand for HFCs is expected to increase globally, because of increased growth in the demand for refrigeration and air conditioning. The demand for HFCs in developing countries is estimated to be 800% greater than in developed countries, by 2050.

Regulation under Montreal Protocol
Partly based on this research, the eight nation-states and territories of Micronesia and the Republic of Mauritius have proposed to regulate these HFCs under the Montreal Protocol, although the treaty does not cover these gases. HFCs, in fact, do not deplete the ozone layer. They are covered by the Kyoto Protocol, but are regarded as outsiders, considering their applications. The Montreal Protocol would have more expertise to control these gases.

Good for the ozone layer
The ozone layer is doing better since ozone-depleting gases (CFCs) have been replaced by alternative gases (HCFCs) in spray cans, refrigerators, and foams, on a global scale. But it is not doing well enough, yet. Two years ago, the Montreal Protocol was adjusted when participating countries decided to accelerate bringing the reduction of HCFC production down to zero: before 2020 in developed countries, and before 2030 in developing countries. Alternative gases are available: the hydrofluorocarbons (HFCs). Although these gases do not contain chlorine and, therefore, do not deplete the ozone layer, they are greenhouse gases, as are their predecessors.

Undoing climate benefits
The 1987 Montreal Protocol restricting the use of ozone-depleting substances helps both to protect the ozone layer and to reduce global warming. Without the protocol, the contribution of ozone-depleting gases to global warming would have been double that of today (currently 20% of the sum of all greenhouse gases). The use of HFCs could undo these climate benefits, significantly.

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