Which country has made the biggest climate commitment?

The US, EU and UK are leading the race to cut emissions targets among the world's biggest economies

Well, it's complicated. The UK has committed to cut emissions at a faster rate than other developed nations, with a target of 68% cuts by 2030. That's measured against its emissions in 1990; over the last few years emissions have been reduced, so measured against the 2018 baseline, for example, the cut needed is smaller.