The United States and China formally join the Paris Agreement

On Saturday the White House announced that the United States and China had signed the necessary paperwork to formally join the Paris Agreement, as the 25th and 26th nations to do so.

Last December more than 190 nations took the initial step to adopt the global agreement to limit emissions at the 21st Conference of the Parties in Paris. However, In order for the agreement to be legally binding, 55 nations representing 55% of emissions must formally join.

Saturday’s action marks major progress towards the 55% target, at the United States and China are the world’s largest emitters of greenhouse gasses and together represent 38% of global emissions, bringing the current total to 40%.

32 more nations have pledged to join the agreement by the end of 2016.

It is unclear what the actual impact of the Paris Agreement will be on deployment of renewable energy. Unlike the 1997 Kyoto Protocol which had binding targets for each participating nation, the plan hinges on voluntary commitments set by each nation: Intended Nationally Defined Contributions (INDCs), which are not legally binding.

After the agreement, famed climate scientist James Hansen called it “worthless words”, stating that there was “no action, just promises”. The International Renewable Energy Agency was more optimistic, calling it a “watershed moment for the global energy transition”, with Director General Adnan Amin noting that it sends a “clear signal to all stakeholders to raise their ambition”.

Regardless, Saturday’s move was praised by environment groups including the Sierra Club. “The Sierra Club applauds President Obama and President Xi for leading the effort to bring the Paris Agreement into force this year and tackle the climate crisis in a meaningful and swift way,” declared Executive Director Michael Brune in an online statement.

“We look forward to continuing to work with governments around the world to bring the Paris Agreement across the finish line and will do our part to build on the promises made in Paris to reduce carbon pollution and ensure clean air, clean water, and healthy communities across the globe.”