World Leaders Poised to Seal Landmark Emissions Deal in Vienna

An international agreement to reduce hydrofluorocarbons could prevent 0.5 degrees of warming by the end of the century, officials say.

In 1987 the Montreal Protocol set the ozone layer on the path to recovery.  In 2016 it could take a bite out of greenhouse gas emissions.

Officials convened in Vienna this week to amend the Montreal Protocol, which phased out ozone-killing refrigerants called CFCs nearly three decades earlier. Now the delegation is nearing an international deal to reduce HFCs, says EPA administrator Gina McCarthy.

“We are seeing all countries coming into this meeting with an incredibly positive and collaborative energy level,” Ms. McCarthy said at a press conference on Thursday.  “There is no country that appears to be standing on the sidelines in this discussion.”

Chlorofluorocarbons (CFCs) are organic compounds composed of carbon, chlorine, and fluorine. CFCs, which were commonly used in air conditioners and aerosol cans, catalyze the conversion of ozone (O3 ) to oxygen (O2 ).  In the 1970s, researchers found that atmospheric CFC levels were weakening Earth’s protective ozone layer.

The Montreal Protocol, signed by all UN and EU member nations in 1987, laid out plans to phase out CFCs.  But in doing so, it created a new problem.

Manufacturers replaced CFCs with hydrofluorocarbons (HFCs).  By comparison, these compounds were ozone-friendly and worked about as well in refrigerants.  But later research indicated that HFCs are potent greenhouse gases, contributing significantly to climate change.

International officials have reconvened in hopes of amending the Montreal Protocol to include HFC limits.  The EPA has stated that a global reduction in HFCs could prevent 0.5 degrees Celsius in warming over the next century.  It doesn’t sound like much, but it’s a moderate step in suppressing climate change.

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