World environmental leaders gather in Kigali, Rwanda, October 10-14 in an effort to finalize an agreement on limiting hydrofluorocarbons (HFCs), gases used as refrigerants that also boost greenhouse warming.

"In the young, rapidly changing and still somewhat mystery-shrouded science of identifying global warming sinks and sources in the Earth's atmosphere, there is at least one family of chemicals that stands out as a beacon of hope. It's called hydrofluorocarbons.

Take one of them, called HFC-134a, for example. While arguments rage among scientists and industries over whether nature or man-inspired activities are emitting more potent global warming gases, such as methane, into the atmosphere, there is no debate about where HFC-134a comes from.

The chemical is totally man-made. It began seeping into the atmosphere in the early 1990s as auto mechanics changed refrigerants in automobile air conditioners as part of their cycle of annual maintenance."

John Fialka reports for ClimateWire October 7, 2016. [2]