Sky News contributor Liz Storer says Greta Thunberg is – at a time when economies are bleeding out – essentially holding world leaders ransom over Twitter and other means to her ridiculous “zero emissions by yesterday” demands.

It comes after the 17-year-old climate activist called out New Zealand Prime Minister Jacinda Ardern on the country’s carbon emissions promises over Twitter.

Ms Ardern responded to Ms Thunberg’s criticism, reaffirming the NZ government does have ambitions regarding climate change.

“We are at a time when world economies are bleeding out, they are suffering like never before” Ms Storer told Sky News host Rita Panahi.

“And we’ve got this 17-year-old holding essentially world leaders ransom over Twitter and other means to her ridiculous zero emissions by yesterday demands.

“She’s 17, what does she know of running a country, what does she know of running an economy? I find it utterly bizarre really.”