Before a parked conference hall in the Spanish capital of Madrid, Swedish climate activist Gretta Thunberg wagged a finger as she shook with fury.
The object of her anger was mere mention of President Donald Trump's decision to pull the US out of the Paris Agreement on climate change. "It is all talk and no action," Ms Thunberg retorted as she delivered a bare-knuckle attack on Trump and other world leaders for their inaction on global warming.