(CNN) Representatives from nearly 200 member countries of the Montreal Protocol agreed on a deal to reduce emissions of powerful greenhouse gases at a summit Saturday in Kigali, Rwanda.

The landmark deal will reduce the use of hydrofluorocarbons, or HFCs, the world's fastest-growing greenhouse gases, the UN Environment Program said in a statement.

HFCs are potent greenhouse gases commonly used in refrigeration and air conditioning instead of other ozone-depleting substances.

"The amendment to the Montreal Protocol on Substances that Deplete the Ozone Layer endorsed in Kigali today is the single largest contribution the world has made towards keeping the global temperature rise 'well below' 2 degrees Celsius, a target agreed at the Paris climate conference last year," the UN agency said in a statement Saturday.

According to the agency, the agreed reduction in HFCs could prevent up to 0.5 degrees Celsius (0.9 degrees Fahrenheit) of global warming by the end of this century.

The deal was reached at a Meeting of the Parties to the Montreal Protocol, which started Thursday. Several high-profile leaders attended the meeting, including US Secretary of State John Kerry.

"It is not often you get a chance to have a 0.5-degree centigrade reduction by taking one single step together as countries -- each doing different things perhaps at different times, but getting the job done," Kerry said in a speech Friday.

"If we continue to remember the high stakes for every country on Earth, the global transition to a clean-energy economy is going to accelerate."

The European Union also welcomed the deal.

Miguel Arias Cañete, EU commissioner for climate action and energy, described it as "huge win for the climate" and the first step toward delivering on promises made on climate change in Paris in December.

The agreement in Kigali comes only days after enough countries ratified the Paris Agreement on climate change -- which calls for the world to become carbon neutral this century -- to become international law.

"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 Erik Solheim, executive director of the UN Environment Program.

Today, nearly 200 countries took an historic step to #ActOnClimate for future generations by phasing down HFCs: https://t.co/AbE72ztIeO pic.twitter.com/f2wUyaLTt3 — The White House (@WhiteHouse) October 15, 2016

President Barack Obama also hailed the Kigali deal.

"Today's agreement caps off a critical 10 days in our global efforts to combat climate change," the US leader said. "In addition to today's amendment, countries last week crossed the threshold for the Paris Agreement to enter into force and reached a deal to constrain international aviation emissions.

"Together, these steps show that, while diplomacy is never easy, we can work together to leave our children a planet that is safer, more prosperous, more secure and more free than the one that was left for us."

Growing demand for cooling

The rapid increase in HFC emissions -- put by the UN agency at 10% a year -- is due in part to a growing demand for cooling, particularly in developing countries with hot climates and an expanding middle class, the agency said.

The agreement includes provisions for hot countries to reduce their use of HFCs at a slower rate. Developed countries will start to reduce the use of HFCs by 2019, while developing nations have been given a longer time frame in which to freeze their use of the damaging gases.

Funding for measures to reduce HFC use and research into alternatives is to be finalized next year, the UN agency said.

Kigali amendment to the Montreal Protocol is adopted at 6:55 am of 15th Oct. 2016 after 24 hrs and 55 min nonstop! pic.twitter.com/V9Sr3tO5Tf — Faustin MUNYAZIKWIYE (@FaustinMUNYAZIK) October 15, 2016

Kerry recalled how the world's nations had worked together on climate change since first meeting in the 1980s in Montreal in a bid to protect the world's fragile ozone layer from ozone-depleting chemicals such as chlorofluorocarbons.

"Thanks to the cooperation and the courage that we summoned at that critical time almost 30 years ago, the hole in the ozone layer -- which had been growing at an alarming rate, and which was the reason that we came together -- that hole is now shrinking, and it's on its way to full repair," he said.

"So we proved that we can make a difference. We proved that science has a value. We proved that if we come together in a forum like this, we can actually do things that affect the entire planet."

Kerry also acknowledged that HFCs had turned out not to be the best solution for the problem of ozone depletion.

"We replaced the ozone depleting substances, but we came to understand the hard way that HFCs may be safe for the ozone layer, but they are disastrous for our climate, in many cases thousands of times more damaging than carbon dioxide," he said.

Used in everyday household items such as refrigerators and air conditioners, he said, "in a single year, these substances emit as much CO2 equivalent as nearly 300 coal-fired power plants."

The head of Rwanda's climate change unit, Faustin Munyazikwiye, also welcomed the world's commitment on HFCs after long hours of negotiations in Kigali.

"We did it!" he tweeted.