Scott Morrison probably isn’t particularly familiar with the Nobel prize-winning economist William Nordhaus. But if he were, the Prime Minister might find a place for the US sage of climate economics on his political dartboard.

It was Nordhaus who in 2015 coined the term “climate club”. He envisaged a group of countries, sharing an ambitious emissions-reduction program, that would slap tariffs on dirty outsiders to stop them free-riding on all the club’s hard work.