A group of the world's most influential scientific advisors have penned a joint letter saying the need for urgent climate action is unequivocal.

This comes as government leaders head to Glasgow for the COP26 summit, while the United Nations says countries' proposed carbon-cutting plans need to be boosted by nearly 700-percent. 

Māni Dunlop speaks to the New Zealand Prime Minister's Chief Science Advisor Professor Dame Juliet Gerrard, who has also signed the letter.