World powers make giant step on emissions

QWhy is the US/China announcement important?

AIt is the first time the two most powerful economies have ratified a climate change treaty. The Paris deal is intended to cut greenhouse gas emissions across the globe. The UN wants to limit the rise in the global average temperature to 2C (3.6F) by the end of the century.

QWhat does it mean?

AThe Paris deal might have been signed last year but it meant little without the two biggest greenhouse gas emitters ratifying the treaty. Yesterday’s announcement will put pressure on other G20 nations to move faster with their pledge to phase out subsidies to fossil fuels.

QSo what happens next?

AWhile yesterday’s announcement ends some uncertainty, the Paris Agreement is only legally binding if it is ratified by at least 55 countries who are responsible for 55 per cent of global carbon emissions. Before China made its announcement, the 23 nations that had so far ratified the deal accounted for just over one per cent of emissions. The addition of China and the US takes the tally to 39 per cent. Britain, a signatory to the Paris agreement, is still to ratify it but is now likely to follow suit.

QWhy have they only signed now?

AThe climate deal announcement is a coup for China on the eve of the G20 summit, which it is hosting. It also allows Barack Obama to bow out of the US presidency at the end of the year with ratification in place.

QWhat is the likely impact?

AIt depends on how one views it. Campaigners insist it will help to save the planet from man-made global warming, while sceptics will argue it will make oil and other traditional energy supplies more expensive. There is also suspicion that some nations may not stick to their emissions targets given that they are not legally binding. Even if they do, observers have calculated that all of the targets, if delivered, will only curb warming by 2.7C. This is well above, not well below, the 2.0C goal.