KIGALI, Rwanda — Negotiators from more than 170 countries on Saturday reached a legally binding accord to counter climate change by cutting the worldwide use of a powerful planet-warming chemical used in air-conditioners and refrigerators.
The talks in Kigali, the capital of Rwanda, did not draw the same spotlight as the climate change accord forged in Paris last year. But the outcome could have an equal or even greater impact on efforts to slow the heating of the planet.
President Obama called the deal “an ambitious and far-reaching solution to this looming crisis.”
Secretary of State John Kerry, speaking to fellow negotiators in Kigali, said, “It is likely the single most important step we could take at this moment to limit the warming of our planet and limit the warming for generations to come.”
“It is,” Mr. Kerry added, “the biggest thing we can do in one giant swoop.”
While the Paris agreement included pledges by nearly every country to cut emissions of heat-trapping carbon dioxide from the fossil fuels that power vehicles, electric plants and factories, the new Kigali deal has a single target: chemical coolants called hydrofluorocarbons, or HFCs, used in air-conditioners and refrigerators.
HFCs are just a small percentage of greenhouse gases in the atmosphere, but they function as a sort of supercharged greenhouse gas, with 1,000 times the heat-trapping potency of carbon dioxide.
The Kigali deal was seven years in the making, and is a compromise between rich nations and poorer, hotter ones, including some where rising incomes are just starting to bring air-conditioners within reach. Wealthier nations will freeze production of HFCs more quickly than poorer countries, though some nations, including those in Africa, elected to phase the chemicals out more rapidly than required, citing the grave threats they face from climate change.
While the Paris pledges are broad, they are also voluntary, often vague and dependent on the political will of future world leaders. In contrast, the Kigali deal includes specific targets and timetables to replace HFCs with more planet-friendly alternatives, trade sanctions to punish scofflaws, and an agreement by rich countries to help finance the transition of poor countries to the costlier replacement products.
So, narrow as it is, the new accord may be more likely to yield climate-shielding actions by industry and governments, negotiators say. And given the heat-trapping power of HFCs, scientists say the Kigali accord will stave off an increase of atmospheric temperatures of nearly one degree Fahrenheit.
