When children returned to school after several months at home because of the first wave of the coronavirus pandemic, one of them was the 17-year-old Swedish climate activist Greta Thunberg. She had taken a gap year to spread her message about runaway global warming, and in August 2020 posted a photo of herself on Instagram with her satchel, commenting that ‘it feels so great to finally be back in school again’.

Thunberg, who has a form of autism called Asperger Syndrome, rose to fame in 2017 for leaving school every Friday to protest outside the Swedish Parliament about political inaction on the climate crisis. Over three years her #FridaysforFuture demonstrations mobilised hundreds of thousands of students to take similar action, and Thunberg has addressed several international climate summits and meetings of world leaders. The school strikes coincided with the rise of Extinction Rebellion (XR), a UK-based movement that shares her determination on climate change: from October 2018, thousands of protestors blocked traffic, occupied landmarks, stripped off in Parliament and generally made a nuisance of themselves. Copycat groups sprang up in other countries.

Thunberg and XR have contributed to driving the climate crisis up the public and political agenda. In May 2019 the UK Parliament became the first national legislative body to declare a climate emergency – with no binding policy commitments attached – and a month later a YouGov poll showed public concern about the environment at record levels. In December 2019, New Scientist summarised the impact of Thunberg and XR under the headline: ‘The year the world started to wake up to climate change’.

Have Thunberg and XR succeeded where traditional environmental charities and NGOs have failed? After all, scientists and experts have been aware of the dangers of climate change for decades. In 1972 the Club of Rome published The Limits to Growth, predicting ecological collapse, and 20 years later the Union of Concerned Scientists issued a warning of ‘vast human misery’ if the world didn't change its ways. Greenpeace, probably the world's most famous environmental body, has campaigned fiercely against powerful fossil fuel interests, while WWF has been tracking the decline of biodiversity since 1970 with its Living Planet Index.