Here is an invigorating portrait of one of Europe’s most distinguished scientists, caught at the very point of morphing into a public intellectual and vehement campaigner. In 2017, Swiss biophysicist Jacques Dubochet won the Nobel prize in chemistry – jointly with Richard Henderson of the MRC Laboratory of Molecular Biology in Cambridge and Joachim Frank of Columbia in New York – for his work on cryo-electron microscopy, freezing biomolecules in mid-movement and so rendering them visible for the first time; this was a great leap forward for pharmacy and medicine.

The snowy-haired Dubochet, who did his important work at the European Molecular Biology Laboratory in Heidelberg before returning to Lausanne, is shown to be at first bemused and a little flustered by the hordes of excitable photographers who descend on his tranquil campus, clamouring for interviews and demanding a soundbite explanation of his work for the TV news. But Dubochet is no innocent: he was a committed anti-nuclear campaigner in Germany in the “Atomkraft? Nein Danke” era of the 80s, and the film shows it dawning on Dubochet that he can use his new platform to campaign on the new issue that he’s passionate about – the climate crisis.

Dubochet thus becomes a participant in climate-strike demos, beaming at young people’s idealism, appearing alongside Greta Thunberg, and becoming enraged at his fellow Swiss for their complacent insularity and at journalists for their supposed neutrality, and failure to report the crisis. He also – just maybe – becomes a little bit intoxicated by his own celebrity, a possibility hinted at during a discussion over the family dinner table. This is a thoroughly worthwhile documentary, although there is one subject I’d like to hear Dubochet address: as an anti-nuke veteran, does he have any time for environmentalists who believe that nuclear power might not be as evil as all that?

• Citizen Nobel is released on 16 December on True Story.