A deal to reduce greenhouse gases far more powerful than carbon dioxide has been signed by about 150 countries.

The agreement divides countries into three groups with different deadlines to reduce factory-made hydrofluorocarbon gases, which are used in fridges, air-conditioning, some inhalers and insulating foam.

The developed nations, including most of Europe and the US, will reduce their use of the gas by 10% before 2019, reaching 85% by 2036.

More than 100 developing countries, including China, the world's worst polluter, will freeze their use of the gas by 2024.

A small group of countries, including India, Iran, Iraq, Pakistan and some Gulf states negotiated a later start in 2029.


That date is two years earlier than India, the world's third-worst polluter, had initially suggested.

These countries will then reduce their use gradually.

Four degrees of global warning could mean an end to humanity

Environmental groups say they hope the deal, which was agreed at a meeting in Rwanda's capital, Kigali, can cut global warming by a half-degree celsius by the end of this century.

Durwood Zaelke, president of Institute for Governance and Sustainable Development, said the agreement gets about 90% of the way there, with a statement from his group describing it as the "largest temperature reduction ever achieved by a single agreement".

Clare Perry, UK climate campaign leader with the Environmental Investigation Agency, said: "Compromises had to be made, but 85% of developing countries have committed to the early schedule starting 2024, which is a very significant achievement."

David Doniger, climate and clean air program director with the Natural Resources Defense Council, said the deal is "equal to stopping the entire world's fossil-fuel CO2 emissions for more than two years."

How you can stop global warming

Small island states, such as those in the Pacific, had called for quicker action, saying that they face the biggest danger from climate change.

Mattlan Zackhras, representing the Marshall Islands, said: "(The deal) may not be entirely what the islands wanted but it is a good deal.

"We all know we must go further and we will go further."

HFCs were introduced in the 1980s to replace ozone-depleting gases.

But they can be 100,000 times more powerful than carbon dioxide as greenhouse gases and the threat grew as sales of fridges and air conditioning increased in developing economies such as China and India.