China has ratified Paris climate agreement, state media says

China has ratified the Paris agreement on climate change, according to state media, a key move by the world's biggest polluter that brings the deal a major step closer to coming into force.

The National People's Congress legislature voted to adopt "the proposal to review and ratify the Paris Agreement", the official Xinhua news agency said.

The Paris pact calls for capping global warming at well below two degrees Celsius, and 1.5C if possible, compared with pre-industrial levels.

China is responsible for about 25 per cent of global carbon emissions, with the US in second place on about 15 per cent, making their efforts crucial in the fight against warming.

The Paris deal will come into force 30 days after at least 55 countries, accounting for 55 per cent of global greenhouse gas emissions, have ratified it.

US President Barack Obama is due to arrive in China later on Saturday for a G20 summit, and is expected to announce the formal joining of the Paris climate accord with President Xi Jinping.

Greenpeace East Asia's senior climate policy adviser Li Shuo said it was time for the Paris accord to "move from agreement to action".

"Political ambition must keep up with rising sea levels faced by vulnerable communities around the world."

"Xi and Obama should seize the opportunity to lead the world's 20 wealthiest nations by joining and building on the Paris Agreement."

The world's top two polluters should "pressure" other G20 members to ratify the agreement, Greenpeace added.

Until Saturday only 23 had done so among the 175 signatories, including France and many island states threatened by rising sea levels but who only produce a tiny proportion of the world's emissions.

The accord sets ambitious goals for capping global warming and funnelling trillions of dollars to poor countries facing an onslaught of climate damage.

Ratifying the agreement fits with Beijing's domestic political agenda of being seen to make efforts to clean up the environment, after years of breakneck industrial development led to soaring air, water and ground pollution.

The scourge is estimated to have caused hundreds of thousands of early deaths, and is the source of mounting public anger.

China has previously committed to its emissions peaking "around 2030", a declaration made on an earlier visit by Obama, when the US leader announced a target to cut emissions 26-28 percent below 2005 levels by 2025.

AFP