One of the most influential voices calling for a climate rebellion is Guardian columnist George Monbiot.

A former BBC producer, he's written several books, including the classic Heat: How to Stop the Planet from Burning, which was published in 2006.

Since last year, Monbiot has been speaking at events organized by Extinction Rebellion. It's a decentralized international group calling for system change to address the climate crisis.

Below, you can read a transcript and watch a video of a memborable speech by Monbiot delivered in London on October 7 as part of an "International Week of Rebellion".

George Monbiot's speech

"For decades, they called people like us 'mad'.

"And when there were only a few of us numbering in the thousands, it hurt. Yeah, it hurt.

"But now that there are millions of us, it doesn't hurt anymore. We own the label. Yes, we are mad.

"We're mad as hell and we're not going to take it anymore.

"For decades, they called us weird. And when there were only a few of us, that hurt.

"But you know the etymology of the word weird? It's from the old English wyrd, which means destiny.

The weird are destinated to change the world. We own this label. We wear it with pride.

"Those of us—who because we have a different view of the world and see things differently have been marginalized for years—have found each other. And have found a way of projecting those views that were marginal into the mainstream.

"It is no coincidence that the person who has done more than anyone else to change the entire global conversation on climate breakdown has Asperger's.

"Humanity cannot survive if everyone is looking at the world in the same way.

"From our earliest origins, groups who could see the world in different ways had higher chances of survival than those who only saw it in one way.

"And one of the extraordinary things that Greta Thunberg has done is to get us to talk about this existential crisis in ways we weren't talking about it before.

"But you know, that's only one of them. The other one is to get us to talk about neurodiversity in ways we weren't talking about before.

"Two extraordinary achievements and we honour her for both of those blessings.

"We have been let down by those who've tried to shape our thinking.

"At school, they tend to recognize only one kind of intelligence but actually, we know there are many kinds of intelligence—spatial, holistic, caring, social—and these are the intelligences that we bring forward. The intelligences that will break the spiral of doom the system seems to have set us on.

"These are the intelligences that tell us this system, within which we have been brought up, is a system destined only to destroy. And what do we need? System change.

"System change and rebellion!

"We are constantly told that our demands for system change are politically impossible, they tell us. Politics cannot respond to the demands that you are making. 

"You can bargain with politics but you can't bargain with science.

"There are two realisms here. Two very different realisms. 

"There is political realism, which is highly flexible. And there is physical realism, which is fixed.

"You can't negotiate with that so we are not negotiating with them.

"Fifty years ago, the situationists coined the slogan 'be realistic, demand the impossible.' We should repurpose that slogan: 'Be scientifically realistic. Demand the politically impossible!'

"When we demand it in great enough numbers, when we demand it in the spirit of rebellion, when we demand it without backing down, what is politically impossible today becomes politically inevitable tomorrow.

"We rebel together in all our wonderful weirdness, all our wonderful madness, and in the spirit of the most embarrassing word in the English language: love.

"We rebel in love for each other. We rebel in love for our wonderful living world. We rebel in love for the better people we can become. 

"We rebel against extinction and for life. 

"Extinction (crowd chants: Rebellion).

"Extinction (crowd chants: Rebellion).

"Extinction (crowd chants: Rebellion).

"Thank you."