Washington
WHEN negotiators from nearly 200 countries gathered outside Paris in December for the United Nations summit meeting on climate change, they reached the first agreement to take action on curbing their planet-warming pollution.
This weekend in Vienna, with far less attention, negotiators from those same countries are nearing a deal that many environmentalists have called the most significant action this year to reduce global warming.
While the Paris agreement aims to reduce the use of coal and oil, which produce the carbon dioxide emissions that are the chief cause of global warming, negotiators in Vienna are working on a deal to ban the use of hydrofluorocarbons, chemicals used in air-conditioners...