The United States and China, the two biggest emitters of greenhouse gases, have announced that they will formally ratify the Paris climate change agreement.

The United States and China, the two biggest emitters of greenhouse gases, have announced, during the G20 summit in Hangzhou, that they will formally ratify the Paris climate change agreement in a move that must be seen as a significant advance in the battle against global warming. Speaking in the presence of the Chinese president, Xi Jinping, and United Nations secretary general Ban Ki-moon, US president Barack Obama confirmed the decision, the result of weeks of intense negotiations by Chinese and American officials.
Earlier China had announced it would formally ratify the Paris accord with president Xi promising to “unwaveringly pursue sustainable development”.
President Obama commented that the joint announcement showed how the world’s two largest economies were capable of coming together to fight climate change. “”When it comes to combating climate change … we are leading by example” he said.
It is now expected that the Paris agreement will come into force later this year. It means the nearly 200 governments party to it will become obliged to meet emissions-cutting commitments made before the deal was reached last December in Paris. The EU for example has a “national determined contribution” of cutting emissions by 40% by 2030 on 1990 levels, and the US by up to 28% by 2025 compared with 2005.
It would also commit the signatory countries to aspire to keeping temperatures below 1.5C above pre-industrial levels – a task that will require existing pledges to be ramped up – and for rich countries to continue giving climate aid to poorer countries beyond 2020.
David Waskow, the international climate director of the World Resources Institute, a Washington-based think tank, described the US-China announcement as a sign the world’s two largest economies had moved from “making commitments to delivering action”.
“Never before have these two countries worked so closely together to address a global challenge. There’s no question that this historic partnership on climate change will be one of the defining legacies of Obama’s presidency” he said.
“The world finally has a global climate agreement with both the US and China as formal parties,” said Jennifer Morgan, the executive director of Greenpeace International. “This signals a new era in global efforts to address climate change.”
The main significance of the Chinese and US announcements is that is brings ratification of the Paris agreement very much closer. Although the agreement was signed by 180 countries, only 24 of them, representing only 1% of global emissions, have so far ratified it. To become a binding treaty it must be ratified by 55 countries, representing 55% of global GHG emissions and 55% of the population, in order to come into force. The news that the world’s top two emitters – who are together responsible for about 38% of emissions – would formally ratify the deal is therefore a major step towards achieving that.
Shortly before Obama arrived in Hangzhou, China became the 25th country to ratify the agreement. It said the move would “safeguard environmental security” and was “conducive to China’s development interests”.