In the past six weeks, China announced it would be carbon neutral by 2060, and the EU said it would achieve the same target a decade earlier. US Democratic presidential aspirant Joe Biden matched the EU’s undertaking, and last week spelt out plans to “transition” America from a fossil-fuel driven economy and re-sign the Paris Agreement on climate change if he wins next Tuesday’s election. And this week, new Japanese Prime Minister Yoshihide Suga pledged to cut the country's greenhouse-gas emissions to net zero by 2050.

Earlier this year, however, Australian Prime Minister Scott Morrison vaguely predicted Australia will achieve zero net emissions some time during the second half of this century. Morrison further papered over tensions in government ranks by saying the Coalition’s climate change policy is “evolving”.