At the G20 meeting in Japan China and the USA have both announced their intention to ratify the Paris Agreement. This means that he two biggest emitters of greenhouse gases have committed themselves to the principle of moving to a temperature target of below 2 degrees centigrade.

Both countries have now formally lodged their instruments of ratification with the UNFCCC. In total now 26 countries have ratified the agreement which represent 39% of global greenhouse gas emissions. For the Paris Agreement to come into legal force at least 55 countries representing 55% of emissions need to ratify.

Given the USA did not ratify the Kyoto Protocol this is a great step forward towards a global agreement on greenhouse gas mitigation.

The third largest emitter is the European Union (13% of emissions) which needs agree with all member states to ratify the agreement. Of the individual EU countries so far only France and Hungary have complete their domestic ratification processes that will allow the EU ratification process to go ahead.