China has ratified the Paris global climate agreement, state news agency Xinhua reports.

China is the world’s largest emitter of harmful CO2 emissions, which cause climate change.

In December 2015, countries agreed to cut emissions enough to keep the global average rise in temperatures below 2C.

China’s National People’s Congress Standing Committee adopted “the proposal to review and ratify the Paris Agreement” on September 3 at the end of a week-long session.

The Paris deal is the world’s first comprehensive climate agreement. The deal will only come into force legally after it is ratified by at least 55 countries, which between them produce 55% of global carbon emissions.

When the United States – the world’s second-largest emitter – follows China’s lead, it will bump the tally up to 40%.

Before China’s announcement, the 23 nations that had ratified the agreement accounted for just over 1% of emissions.

Analysts warn that the target of keeping temperature rises below 2C is already in danger of being breached.

For 14 consecutive months meteorologists have recorded the hottest month on record.

Average temperatures worldwide are likely to increase more in the coming years as the effect of previous carbon emissions makes itself felt.

The G20 summit in Hangzhou, starting on September 4, is a meeting of leaders from 20 countries.

President Barack Obama has now arrived in China on what is expected to be his last trip to Asia as the US president.

Barack Obama is set to announce on September 3 that the US is formally joining the Paris Agreement.

It is thought that he and China’s President Xi Jinping will make a joint announcement at a bilateral meeting.