0538 GMT November 22, 2019
Nearly 200 countries agreed to end production and consumption of so-called hydrofluorocarbons (HFCs) under an amendment to the 1987 Montreal Protocol on protecting the ozone layer, AFP reported.
HFCs stoke climate change because they are super-efficient at trapping heat in Earth's atmosphere.
By scrapping these substances, say experts, a massive step could be made towards achieving the UN's goal to roll back global warming.
The agreement was greeted by applause from exhausted envoys who worked through the night in Rwanda's capital Kigali to put the finishing touches on the deal.
"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," UN Environment Program chief Erik Solheim declared.
US President Barack Obama said in a White House statement that the agreement was "an ambitious and far-reaching solution to (the) looming crisis" of climate change.
It adds powerfully to the 2015 Paris Agreement, due to take effect next month after crossing the threshold for ratification by signatory countries, Obama said.
"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."
Under the agreement, rich countries will move faster than developing giants to scrapping HFCs – a concession that was a source of regret for some.
The Paris Agreement aims to keep global warming below two degrees Celsius (3.6 Fahrenheit), compared with pre-industrial levels.
Its principal target is carbon dioxide (CO2), emitted especially by coal, oil and gas.
As these sources are the mainstays of the world's energy supply, reducing carbon pollution has been a painfully slow and rancorous affair, marked by bickering over who should shoulder the burden for energy efficiency and the switch to cleaner sources.
Right now, Earth is on track for several degrees of warming by century's end – a scenario that climatologists fear will doom the planet to worse droughts, floods, storms and rising seas.
Eliminating HFCs – which are dealt with under the Montreal Protocol, not the Paris Agreement – could be a relatively swift and easy way to ease the warming and buy time, say specialists.
It could reduce global warming by 0.5 C by 2100, according to a 2015 study by the Institute for Governance and Sustainable Development.
HFCs were introduced in the 1990s to replace chlorofluorocarbons (CFCs) that had been found to erode the ozone layer, the stratospheric shield which protects life on Earth from damaging solar radiation.