#hfc-22

Excerpt from this story from InsideClimate News:

Atmospheric concentrations of a greenhouse gas nearly 13,000 times more potent than carbon dioxide rose faster than ever before over a three-year period starting in 2015, a new study has found. The findings suggest that China and India may not be living up to recent pledges to dramatically reduce emissions of the pollutant.

The gap between the two countries' voluntary pledges to reduce the greenhouse gas—known as HFC-23, a type of hydrofluorocarbon—and the estimates of actual emissions for the pollutant is the equivalent of approximately 103 million metric tons of carbon dioxide per year, or the annual greenhouse gas emissions of 22 million automobiles, according to the U.S. Environmental Protection Agency.

HFC-23 is an unwanted byproduct resulting from the manufacturing of HCFC-22, a chemical used in refrigeration and air conditioning. HCFC-22 replaced chlorofluorocarbons, which were phased out beginning in the 1990s for their role in creating the so-called "ozone hole." Since the international ban began, under the Montreal Protocol, atmospheric ozone concentrations have increased, and is expected to lead to the full recovery of the ozone layer sometime in the middle of the century.

A 2016 addition to the Montreal Protocol, known as the Kigali Amendment, requires companies that manufacture HCFC-22 to destroy HFC-23 to prevent its release into the atmosphere. So far, the United States, China and India have not ratified the agreement. The Trump administration's failure to ratify the Kigali Amendment, despite strong support from U.S. industries, takes pressure off of other countries to do the same, Avipsa Mahapatra, the climate campaign lead for the Environmental Investigation Agency (EIA), a UK-based environmental organization, said.