Image copyright Getty Images Image caption HFCs are commonly used in refrigerators and air conditioning systems

More than 150 countries have reached a deal described as "monumental" to phase out gases that are making global warming worse.

Hydrofluorocarbons (HFCs) are widely used in fridges, air conditioning and aerosol sprays.

Delegates meeting in Rwanda accepted a complex amendment to the Montreal Protocol that will see richer countries cut back their HFC use from 2019.

But some critics say the compromise may have less impact than expected.

Three-way deal

US Secretary of State John Kerry, who helped forge the deal in a series of meetings in the Rwandan capital, said it was a major victory for the Earth.

"It's a monumental step forward, that addresses the needs of individual nations but it will give us the opportunity to reduce the warming of the planet by an entire half a degree centigrade," he told BBC News.

Image caption US Secretary of State John Kerry urged delegates to adopt an ambitious deal

The new agreement will see three separate pathways for different countries.

Richer economies like the European Union, the US and others will start to limit their use of HFCs within a few years and make a cut of at least 10% from 2019.

Some developing countries like China, nations in Latin America and island states will freeze their use of HFCs from 2024.

Image copyright AFP

What is the Montreal Protocol?

International treaty designed to protect the environment against the impact of harmful substances

Created in 1987 following the discovery of a large hole in the Earth's ozone layer over Antarctica

Came into force in 1989 with the main aim of ending the use of chlorofluorocarbons (CFCs)

CFCs replaced by hydrofluorocarbons (HFCs)

Amendment proposed after scientists discovered that, while they pose no threat to the ozone layer, HFCs contribute to global warming by trapping heat radiating off the Earth

The protocol has undergone a number of revisions since it was introduced and has been successful in eliminating more than 100 fluorinated gases

Other developing countries, specifically India, Pakistan, Iran, Iraq and the Gulf states will not freeze their use until 2028.

China, the world's largest producer of HFCs, will not actually start to cut their production or use until 2029.

Image caption Air conditioning units were needed at the conference in Kigali as negotiations dragged into the night

India, will start even later, making its first 10% cut in use in 2032.

"Absolutely it's a historic day," said Durwood Zaelke, from the Institute for Government and Sustainable Development (IGSD), a long time participant in the Montreal Protocol talks.

"We came to get a half a degree of warming out of the system and we are going to walk away with about 90% from the Kigali amendment."

Certainly if the agreement is implemented in full it will make a big difference to global warming. Experts estimate it will remove the equivalent of about 70 billion tonnes of carbon dioxide from the atmosphere by 2050.

"HFCs posed an immediate threat to a safe climate due to their increasing use and high global warming potential, thousands of times more potent than carbon dioxide," said Christian Aid's Senior Policy Advisor, Benson Ireri.

"By agreeing to an early HFC phase down schedule, we've bought ourselves a bit more time to shift to a global low carbon economy and protect the world's most vulnerable people."

Image copyright Getty Images Image caption The deal will mean that new refrigerators will use less harmful cooling gases in the future

But some observers questioned the concessions made to India and China, suggesting they had weakened the overall impact. The target of cutting global warming by 0.5 degrees may not be realised.

"They needed an agreement here as it's seen as an Obama legacy, so the US delegation has been pretty aggressive in making China and India get to an agreement," said Paula Tejon Carbajal from Greenpeace International.

"It's an incremental step towards 0.5 degrees but its not there yet, they say that the market will work to get us there, but we are not there yet."

The US Secretary of State believes that the science underpinning the deal is sound. He is confident that it will have a huge impact on warming.

"I feel very positive about where we are, we ran all the numbers and everybody feels confident that the integrity of the substance of this is there," he told the BBC.

Supporters argue that this agreement in Kigali will build on the foundations laid by the Paris climate agreement, signed by over 190 countries last December, and which becomes operational early in November.

They also point to the past history of the Montreal Protocol - over 100 fluorinated gases have been eliminated in the agreement's 30 year history. Once the regulation has been passed, industry rapidly develops alternatives.

"The market is going to wash over India, and will sweep them along, they will make the transition a lot faster than the number they put up," said Durwood Zaelke.

"Phase-outs have always driven the market transition so the laggards will be moved along by the market."

There was a sense of quiet jubilation among delegates here when the deal was finally gavelled through in the early hours of Saturday morning.

'It's a big deal," one observer said, "but it could have been bigger."

Follow Matt on Twitter @mattmcgrathBBC and on Facebook.</s>Delegates celebrate a global deal to limit the use of hydrofluorocarbon gases, in a major effort to combat climate change. The agreement was reached at a climate conference in the Rwandan capital Kigali on Saturday morning. US secretary of state John Kerry hails it a ‘monumental step forward’
• Climate change: global deal reached to limit use of hydrofluorocarbons</s>KIGALI, Rwanda – Nearly 200 nations have reached a deal, announced Saturday morning after all-night negotiations, to limit the use of greenhouse gases far more powerful than carbon dioxide in a major effort to fight climate change.

The talks on hydrofluorocarbons, or HFCs, were called the first test of global will since the historic Paris Agreement to cut carbon emissions was reached last year. HFCs are described as the world’s fastest-growing climate pollutant and are used in air conditioners and refrigerators. Experts say cutting them is the fastest way to reduce global warming.

President Barack Obama, in a statement Saturday, called the new deal “an ambitious and far-reaching solution to this looming crisis.”

The agreement, unlike the broader Paris one, is legally binding. It caps and reduces the use of HFCs in a gradual process beginning by 2019 with action by developed countries including the United States, the world’s second-worst polluter. More than 100 developing countries, including China, the world’s top carbon emitter, will start taking action by 2024, when HFC consumption levels should peak.

A group of countries including India, Pakistan and some Gulf states pushed for and secured a later start in 2028, saying their economies need more time to grow.

Environmental groups had hoped that the deal could reduce global warming by a half-degree Celsius by the end of this century. This agreement gets about 90 percent of the way there, said Durwood Zaelke, president of the Institute for Governance and Sustainable Development.

Zaelke’s group said this is the “largest temperature reduction ever achieved by a single agreement.”

The new agreement is “equal to stopping the entire world’s fossil-fuel CO2 emissions for more than two years,” David Doniger, climate and clean air program director with the Natural Resources Defense Council, said in a statement.

It is estimated that the agreement will cut the global levels of HFCs by 80 to 85 percent by 2047, the World Resources Institute said in a statement.

Experts said they hope that market forces will help speed up the limits agreed to in the deal.

HFCs were introduced in the 1980s as a substitute for ozone-depleting gases. But their danger has grown as air conditioner and refrigerator sales have soared in emerging economies like China and India. HFCs are also found in inhalers and insulating foams.

Major economies have debated how quickly to phase out HFCs. The United States, whose delegation was led by Secretary of State John Kerry, and Western countries want quick action. Nations such as India want to give their industries more time to adjust.

“Thank God we got to this agreement that is good for all nations, that takes into consideration all regional and national issues,” said Taha Mohamed Zatari, the head of Saudi Arabia’s negotiating team.

Small island states and many African countries had pushed for early timeframes, saying they face the biggest threat from climate change.

“It may not be entirely what the islands wanted, but it is a good deal,” Mattlan Zackhras, the minister-in-assistance to the president of the Marshall Islands, said in a statement. “We all know we must go further, and we will go further.”

The U.N. says the next meeting in 2017 will determine how much of the billions of dollars needed to finance the reduction of HFCs will be provided by countries.

HFCs are less plentiful than carbon dioxide, but Kerry said last month that they currently emit as much pollution as 300 coal-fired power plants each year. That amount will rise significantly over the coming decades as air conditioning units and refrigerators reach hundreds of millions of new people.

HFCs don’t harm the ozone layer like chlorofluorocarbons and similar gases that were eliminated under the 1987 Montreal Protocol. The entire world ratified that agreement, helping to repair holes in the ozone that helps shield the planet from the harmful rays of the sun. The aim of this meeting was to attach an amendment to that treaty dealing specifically with HFCs.

“This is about much more than the ozone layer and HFCs. It is a clear statement by all world leaders that the green transformation started in Paris is irreversible and unstoppable,” Erik Solheim, executive director of the U.N. Environment Program, said in a statement.

Environmental groups were already turning attention Saturday to other greenhouse gases like carbon dioxide.

“Acting on HFCs does not exempt us from acting on CO2 or other important greenhouse gases like methane. We emit considerably more carbon, and it lingers in the atmosphere for more than 500 years,” Carol Werner, executive director of the Environmental and Energy Study Institute, said in a statement.</s>Nearly 200 nations have reached a deal to limit the use of greenhouse gases far more powerful than carbon dioxide in an effort to tackle climate change.

US President Barack Obama called the deal – announced yesterday morning after all-night negotiations in Rwanda – “an ambitious and far-reaching solution to this looming crisis”.

Hydrofluorocarbons (HFCs) are used in air conditioners and refrigerators and experts say cutting them is the fastest way to reduce global warming.

The agreement is legally binding – unlike last year’s Paris Agreement to cut carbon emissions. It caps and reduces the use of HFCs in a gradual process beginning by 2019 with action by developed countries including the US, the world’s second-worst polluter. More than 100 developing countries, including China, the world’s top carbon emitter, will start taking action by 2024.

A small group of countries including India, Pakistan and some Gulf states pushed for and secured a later start in 2028, saying their economies need more time to grow. That’s three years earlier than India, the world’s third-worst polluter, had first proposed.

“It’s a very historic moment, and we are all very delighted that we have come to this point where we can reach a consensus and agree to most of the issues that were on the table,” said India’s chief delegate, Ajay Narayan Jha.

Environmental groups had hoped that the deal could reduce global warming by a half-degree Celsius by the end of this century. This agreement gets about 90 per cent of the way there, said Durwood Zaelke, president of the Institute for Governance and Sustainable Development. He said this is the “largest temperature reduction ever achieved by a single agreement”.

The agreement is “equal to stopping the entire world’s fossil-fuel CO2 emissions for more than two years,” said David Doniger, climate and clean air programme director with the US Natural Resources Defence Council.

HFCs were introduced in the 1980s as a substitute for ozone-depleting gases. But their danger has grown as air conditioner and refrigerator sales have soared in emerging economies such as China and India.</s>KIGALI, Rwanda — Nations have reached a deal to limit the use of greenhouse gases far more powerful than carbon dioxide in a major effort to fight climate change.

The talks on hydrofluorocarbons, or HFCs, have been called the first test of global will since the historic Paris Agreement to cut carbon emissions was reached last year. HFCs are described as the world’s fastest-growing climate pollutant and are used in air conditioners and refrigerators.

The agreement announced Saturday morning, after all-night negotiations, caps and reduces the use of HFCs in a gradual process beginning in 2019 with action by developed countries including the United States, the world’s second worst polluter. More than 100 developing countries, including China, the world’s top carbon emitter, will start taking action in 2024.

A small group of countries including India, Pakistan and some Gulf states pushed for and secured a later start in 2028, saying their economies need more time to grow. That’s three years earlier than India, the world’s third worst polluter, had first proposed.

Environmental groups had hoped that the deal could reduce global warming by a half-degree Celsius by the end of this century. This agreement gets about 90 percent of the way there, said Durwood Zaelke, president of the Institute for Governance and Sustainable Development.

Zaelke’s group said this is the “largest temperature reduction ever achieved by a single agreement.”

The new agreement is “equal to stopping the entire world’s fossil-fuel CO2 emissions for more than two years,” David Doniger, climate and clean air program director with the Natural Resources Defense Council, said in a statement.

Experts said they hope that market forces will help speed up the limits agreed to in the deal.

“Compromises had to be made, but 85 percent of developing countries have committed to the early schedule starting 2024, which is a very significant achievement,” Clare Perry, UK Climate Campaign Leader with the Environmental Investigation Agency, said in a statement.

HFCs were introduced in the 1980s as a substitute for ozone-depleting gases. But their danger has grown as air conditioner and refrigerator sales have soared in emerging economies like China and India. HFCs are also found in inhalers and insulating foams.

Major economies have debated how fast to phase out HFCs. The United States, whose delegation was led by Secretary of State John Kerry, and Western countries want quick action. Nations such as India want to give their industries more time to adjust.

Small island states and many African countries had pushed for quick action, saying they face the biggest threat from climate change.

“It may not be entirely what the islands wanted, but it is a good deal,” the minister-in-assistance to the president of the Marshall Islands, Mattlan Zackhras, said in a statement. “We all know we must go further, and we will go further.”

HFCs are less plentiful than carbon dioxide, but Kerry said last month that they currently emit as much pollution as 300 coal-fired power plants each year. That amount will rise significantly over the coming decades as air conditioning units and refrigerators reach hundreds of millions of new people.

HFCs don’t harm the ozone layer like chlorofluorocarbons and similar gases that were eliminated under the 1987 Montreal Protocol. The entire world ratified that agreement, helping to repair holes in the ozone that helps shield the planet from the harmful rays of the sun. The aim of this meeting was to attach an amendment to that treaty dealing specifically with HFCs.</s>Countries may sign up to different deadlines for phasing out greenhouse gases used in refrigerators and air conditioners, a U.S. official said on Friday during a summit in Rwanda of some 150 nations meeting to strike an environmental pact.

Jennifer Haverkamp, the U.S. Special Representative for Environment and Water Resources, told Reuters that countries may agree separate timelines for phasing out factory-made hydrofluorocarbon (HFC) gases, which can be 10,000 times more powerful than carbon dioxide as greenhouse gases.

"It’s quite possible that there will be a couple of different groups that countries can slot into, depending on what level of ambition they are able to take on," she said.</s>Nearly 200 nations hammered out a legally binding deal to cut back on greenhouse gases used in refrigerators and air conditioners, a Rwandan minister announced to loud cheers on Saturday, in a major step against climate change.

The deal, which includes the world’s two biggest economies, the United States and China, divides countries into three groups with different deadlines to reduce the use of factory-made hydrofluorocarbon (HFC) gases, which can be 10,000 times more powerful than carbon dioxide as greenhouse gases.

“It’s a monumental step forward,” US secretary of state John Kerry said as he left the talks in the Rwandan capital of Kigali late on Friday.

As Rwanda’s Minister for Natural Resources, Vincent Biruta, began spelling out the terms of the deal shortly after sunrise on Saturday, applause from negotiators who had been up all night drowned out his words.

Under the pact, developed nations, including much of Europe and the United States, commit to reducing their use of the gases incrementally, starting with a 10 per cent cut by 2019 and reaching 85 percent by 2036.

Many wealthier nations have already begun to reduce their use of HFCs.

Two groups of developing countries will freeze their use of the gases by either 2024 or 2028, and then gradually reduce their use. India, Iran, Iraq, Pakistan and the Gulf countries will meet the later deadline.

They needed more time because they have fast-expanding middle classes and hot climates, and because India feared damaging its growing industries.

“Last year in Paris, we promised to keep the world safe from the worst effects of climate change. Today, we are following through on that promise,” said UN environment chief Erik Solheim in a statement.

The deal binding 197 nations crowns a wave of measures to help fight climate change this month. Last week, the 2015 Paris Agreement to curb climate-warming emissions passed its required threshold to enter into force after India, Canada and the European Parliament ratified it.

But unlike the Paris agreement, the Kigali deal is legally binding, has very specific timetables and has an agreement by rich countries to help poor countries adapt their technology.

The United Nations says phasing out HFCs will cost billions of dollars.

But a quick reduction of HFCs could be a major contribution to slowing climate change, avoiding perhaps 0.5 degrees Celsius (0.9 Fahrenheit) of a projected rise in average temperatures by 2100, scientists say.

Environmental groups had called for an ambitious agreement on cutting HFCs to limit the damage from the roughly 1.6 billion new air conditioning units expected to come on stream by 2050, reflecting increased demand from an expanding middle class in Asia, Latin America and Africa.

The HFC talks build on the 1987 Montreal Protocol, which succeeded in phasing out the use of chlorofluorocarbons (CFCs), widely used at that time in refrigeration and aerosols.

The aim was to stop the depletion of the ozone layer, which shields the planet from ultraviolet rays linked to skin cancer and other conditions.
The Obama administration agrees to an international limit on the use of hydrofluorocarbon gases in refrigeration and air conditioning.