Who is this year's environmental hero? Big business.
It happened quietly, but the passage in October in Kigali of an international treaty to limit hydrofluorocarbons (HFCs)—which are potent greenhouse gases—should "abate global warming by up to 0.5° C." That deal went through, perhaps surprisingly, with lots of support from refrigerant companies, which is encouraging news to the climate champions who argue that America's next big steps on carbon reduction will be driven by business, not government.
The half degree Celsius saved by Kigali could be huge, for example by spelling the difference between life and death for coral reefs. Canada has already drafted actions to draw down HFC use.