World leaders discuss ban of climate-busting refrigerants

From Nature:

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Air-conditioning units outside a Hong Kong housing complex.

An article by Scientific American.

After being directed for almost 30 years at substances that destroy ozone, the Montreal Protocol will for the first time target a group of greenhouse gases. Beginning today in Kigali, Rwanda, member states of the United Nations are finalizing the terms of what could be the largest commitment to reducing global warming since the Paris Agreement on climate last December.

Delegates are likely to take till the meeting’s final day on 14 October to hammer out the knotty details of an amendment to the protocol. Ideally, the amendment will set the terms for a rapid phasedown of hydrofluorocarbons (HFCs), the most common of which is the refrigerant HFC-134a, which has 1,430 times more warming potential than carbon dioxide (CO2) over 100 years. The amendment would stop the manufacture of HFCs and then reduce their use over time.

“An ambitious amendment is the quickest and least expensive way to reduce the effects of climate change,” says Durwood Zaelke, president of the Institute for Governance and Sustainable Development, who has been a mainstay at ozone negotiations since almost the beginning of the 1987 treaty. He says a phasedown could prevent the equivalent of 100 to 200 billion tons of CO2 being released into the atmosphere by 2050. That prevention could avert half a degree of warming by the end of the century. Considering that the Paris Agreement’s goal is to keep global average temperature rise by less than 2 °C, an HFC ban offers a significant opportunity.

More from Scientific American.

The Montreal Protocol was adopted after scientists recognized that chlorofluorocarbons (CFCs) were destroying the protective layer of ozone in the stratosphere. Two years later countries began eliminating the chemicals, which had a helpful by-product of releasing fewer …

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