A new deal on greenhouse gases will be "like taking 200 million cars off the road every year," said Catherine McKenna, Canada's minister of environment and climate change in an interview with CBC News.
All 197 signatories to the Montreal Protocol — all the countries of the UN plus the Cook Islands, the Holy See, Niue and the European Union — hammered out a legally binding deal early Saturday to cut back on greenhouse gases used in refrigerators and air conditioners, in a major step against climate change.
The deal, which includes the world's two biggest economies and top polluters — the United States and China — will reduce the use of factory-made hydrofluorocarbon (HFC) gases, which McKenna said are "thousands of times more potent than other greenhouse gases."
The deal, announced following negotiations lasting through the night in Kigali, Rwanda, divides countries into three groups with different deadlines for reaching their HFC targets.
U.S. President Barack Obama, in a statement Saturday, called the new deal "an ambitious and far-reaching solution to this looming crisis." The spokesman for UN Secretary-General Ban Ki-moon called it "critically important."
Under the pact, developed nations, including much of Europe and the U.S., commit to reducing their use of the gases incrementally, starting with a 10 per cent cut by 2019 and reaching 85 per cent by 2036.
Hot, developing countries given more time
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.
China, the world's top carbon dioxide emitter, won't be taking action to curb HFC emissions until 2024, when HFC consumption levels are expected to peak.
Several countries have said they need more time because they have fast-expanding middle classes and hot climates, and because India feared damaging its growing industries.
India's lead negotiator for the deal, Manoj Kumar Singh, said in Kigali that they were "very comfortable." with the deal, which is an amendment to the Montreal Protocol.
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.
Phase-out will cost billions
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 U.S. Environmental Protection Agency Administrator Gina McCarthy said on Saturday that costs were: "reasonable for the kind of reductions we're going to get."
Onus is on businesses, not consumers
McKenna said the deal will not force consumers to replace their air conditioners, but that, in future, products with HFCs will simply no longer be available.
"We're trying to position ourselves well in Canada, and also as a global community, to address the impacts of climate change and put ourselves on a more sustainable path," she said.
Canadians are already feeling the effects of climate change with floods, forest fires and melting ice caps, said McKenna, adding that the cost of inaction "is going to be borne to our children and grandchildren."
May reduce warming by half a degree
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.
This agreement gets about 90 per cent 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."
Hydrofluorocarbons were introduced in the 1980s as substitutes for ozone-depleting chlorofluorocarbons (CFCs). While HFCs do not deplete ozone, they are potent greenhouse gases.
The UN 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 U.S. Secretary of State John 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.
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 Defence Council, said in a statement after the deal was announced.