Five years ago a whole succession of countries declared net zero targets, to the point that it became something of a standard. Half a decade on, how many of those countries are on track to meet that target?

Fifteen, according to a new study from Allianz. Those 15 countries have already reduced their emissions by a third, which means they would be on track for 2050 if they keep up that pace. A further 20 countries have made good progress, reducing emissions by at least a fifth. They would be a...