London Mayor Sadiq Khan was widely mocked on social media this week for activating a "climate clock" that shows how much time the world has left to reduce greenhouse emissions.

"Today with His Majesty King Charles III we launched the Climate Clock — a visual reminder of the urgency of the climate crisis," Khan posted on Twitter along with a video of himself activating the clock with King Charles III.

The clock’s countdown started at 6 years and 24 days, which climate activists say is the deadline to meet the Paris Agreement guideline to stop the Earth from heating more than 1.5 degrees Celsius.

"The climate emergency poses a threat not only to the future of our city but to the future of our world and that is why it must remain a key priority," Khan added.

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Khan’s post was "ratioed" and widely mocked on Twitter, as many users likened him to climate activist Greta Thunberg and said they doubt that action must be taken in six years.

"What a load of nonsense," British politician David Kurten tweeted. "There is no climate emergency."

"Leave Us Alone," Canadian conservative author and podcast host Jordan Peterson posted.

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Khan, one of the most prominent supporters of the climate change movement, has been criticized in the past over his reluctance to condemn private jet usage in London, as well as the air travel miles he has racked up since taking office while warning about climate change.

"Hasn’t he heard of Zoom?" Khan’s critics tweeted in October when the liberal mayor flew 7,000 miles across the globe from the United Kingdom to Argentina to speak at a climate change summit.

A spokesperson for Khan's office told Fox News Digital that the mayor cycles and uses public transport whenever possible and flies commercial, not private, if no appropriate alternative exists.