A global deal on climate change is a step closer tonight, after the world's two biggest polluters agreed to ratify to the Paris agreement.
In a landmark moment, both China and the United States have formally joined the Paris climate agreement.
It's a step that New Zealand hasn't taken yet, and the moves will put more pressure on our Government to follow suit.
"We have a saying in America that you have to put your money where your mouth is," said US President Barack Obama. "And when it comes to combating climate change, that's exactly what we're doing."
Until now, the countries that had ratified the Paris agreement accounted for just over 1 percent of carbon emissions. But the inclusion of the two superpowers pushes that figure up to 40 percent.
"Today we are moving the world significantly closer to the goal we have set," said Mr Obama.
Chinese President Xi Jinping has promised to work with the US to implement the Paris agreement and create an action plan to promote sustainable energy and entrepreneurship.
Last year 195 nations met in Paris to sign the climate agreement. To take effect, 55 states making up 55 percent of the world's emissions must ratify it.
With China and the US on board, 26 countries have now done that, responsible for 40 percent of total emissions.
New Zealand has yet to formally join up.
"With China and United States now ratifying the Paris agreement, the New Zealand Government has nowhere to hide," said Greenpeace New Zealand executive director Russel Norman.
Climate Change Minister Paula Bennett was unavailable for comment today, but she has said the Government plans to ratify the agreement by November.
"It may well happen, but the more important thing is, will the New Zealand Government actually introduce policies that will cut greenhouse gas emissions?" said Dr Norman.
The European Union and the UK are also yet to get on board. But now the two most powerful and dirtiest nations have signed up, our Government has been left playing catch-up.