Climate Central: The road to a phaseout in the production and use of a rapidly growing and extremely powerful global warming pollutant proved bumpier than expected when diplomats gathered in Bangkok last week for the latest round of ozone treaty talks. For much of this year, momentum had been building behind a U.S.-backed amendment to the Montreal Protocol, which is the 1987 treaty that has protected the planet's ozone layer from the ravages of ozone-depleting chemicals.
The amendment, sponsored by the U.S., Canada,...