China and the USA announced at the G20 meeting last week that they are both going to ratify the Paris climate change agreement, to the breathless excitement of many observers. If President Xi says China will ratify, then it most certainly will, but since the obligation would only be for Chinese emissions to plateau by 2030, this will do nothing to stop the rise in emissions for the next 15 years.
If President Obama says the USA will ratify, he relies on the American Senate to vote in favour, which it may well do in light of the Chinese decision. However, as the outgoing president, his word may not carry as much weight as in previous years and, in the fractious world of politics across the pond, who knows what might happen?
In any case, ratification is merely the first step in a process that, while it technically binds signatories to achieve certain targets, provides no enforceable sanctions. It remains to be seen how many countries will willingly compromise the health of their economies in the name of drastic emissions reduction, particularly in view of the current state of technology. The USA and China most certainly won’t.