There's not much the international community does manage to agree on at the moment. Climate change though is a welcome exception.
The latest deal is to cut global emissions of hydrofluorocarbons, or HFCs.
"We're talking about reducing HFCs by about 70 billion metatonnes with this one action," says Gina McCarthy, administrator of the US Environmental Protection Agency.
"That's about equal to 2000 coal-fired power plants. That's about 10 times the emissions of the US in a single year."
HFCs are found mainly in fridges and air conditioning units. And as the world gets hotter, the developing world gets richer and demand for air conditioning grows - so HFC emissions are rising fast.
They were meant to be a substitute for CFCs - or chlorofluorocarbons - blamed in the 1980s for destroying the ozone layer. CFCs were gradually phased out after states universally ratified the Montreal Protocol in 1987. But HFCs are greenhouse gases too, and around 4000 times more toxic than carbon dioxide, which is why the Montreal Protocol has now been amended.
"I think that 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," says John Kerry, US Secretary of State.
There are three phases to this deal. Richer countries, like those in the European Union and the United States, will freeze HFC use from 2018.
Most other developing countries like China, Brazil and all of Africa will start in 2024. And a smaller group, including Pakistan, Iran and India, will freeze HFCs from 2028. Each group then commits to a gradual phasing out of emissions.
But does it go far enough when countries like India don't need to act for more than a decade? Analysts say the adoption of substitute technologies may give the process a momentum of its own.
Efforts to combat global warming could not come fast enough, but this month has seen some significant landmarks, with a deal struck to reduce global airline emissions.
And enough countries are ratifying the Paris Agreement on climate change for it to go into effect in November - days before the US election.
Climate change is clearly a legacy issue for Barack Obama as he prepares to leave the Oval Office.Newshub.