Cook Islands is the 81st country to ratify the 2016 agreement.
HFC gases had earlier replaced the more ozone-destructive CFC gases that were previously used for refrigeration and other uses. The HFCs were found to be less stable in the lower atmosphere, enabling them to break down before reaching the ozone layer.
Once released in the atmosphere, HFCs decompose within a few months to a couple of decades, as compared with CO2, which lasts for well over a century.
But now that thinking has changed.
Under the Kigali Amendment, countries have committed to reduce the production and consumption of HFCs by more than 80 per cent over the next 30 years.
HFCs are chemicals used in refrigeration, air-conditioning, insulating foams, and aerosols. They are extraordinarily potent climate pollutants, with hundreds to thousands of times the heat-trapping power of CO2, according to the latest thinking.
As a result, even small concentrations of HFCs in the atmosphere can significantly harm the planet, scientists now say.
And HFC atmospheric concentrations have been rising rapidly as HFC use has grown since the 1990s.
According to Steve Anderson of Andersons, a renewable energy company, the Cook Islands phased out CFCs under the Montreal Protocol – and then replaced them with HFCs.
These have since been found to have global warming potential, and so are now being replaced where possible with hydrocarbons.
This process is ongoing, complicated by hydrocarbon flammability, and the proposed upcoming change to CO2 as a refrigerant, Anderson says.
However, CO2 while non-flammable, requires hardware that is complex and expensive.
The Cook Islands is following the lead of more developed countries is determining which path to follow, and also watching as new gases and technologies evolve.
- Gray Clapham