What do you do when the human systems that control the world are sending us towards destruction? You rebel against those systems. 

That was the conclusion reached by the founders of Extinction Rebellion. They examined climate science and what it predicted. They examined what previous protest movements had done and how they approached their objectives. Then they set out to plan a campaign to draw attention to the shocking lack of progress on tackling climate change. 

Letters to MPs, polite protest, local action, none of these approaches was having any impact on the suicidal trajectory of big business and government.