HERE’S a trivia question for you. What do Bhutan and Suriname have in common? If you said that they are the only countries that, in effect, add no greenhouse gases to the air, a state of grace known as net zero, then well done – though you might want to get out more.

Even if you aren’t a climate obsessive, net zero is a phrase you have probably heard. Greta Thunberg talked about it last month at the World Economic Forum meeting in Davos, Switzerland. Last year, the UK and France became the first major economies to legally commit to achieving it; both chose …