Credit: The 5Cs

About 170 countries gathered at the United Nations for a ceremonial signing of the landmark Paris agreement on Friday, in a powerful display of global efforts to fight climate change.

A dozen countries – mainly the small island states at risk of being drowned by rising seas – said they would take the additional step on Friday of ratifying or granting legal approval to the agreement.

The renewed commitments, and the personal appearance at the UN by about 60 heads of state, delivered a sense of momentum to efforts to bring the agreement into force far earlier than had originally been hoped.

The agreement reached in Paris by 196 countries still needs formal approval from 55 countries representing 55% of global greenhouse gas emissions to come into force. In some cases, that means a vote in parliament.

The US, China and India – the three biggest climate…