The death of a British passenger and injuries to others on a Singapore Airlines passenger flight from London has underlined the potential dangers of turbulence. But what causes turbulence, how much risk does it pose – and is the climate crisis making it worse? On international scheduled flights, fatalities directly caused by turbulence are incredibly rare. Pilots are usually able to give advance warning of most types of turbulence and ensure all on board are strapped in. On smaller private planes or business jets, serious injuries or deaths have been more frequent, with the US National Transport Safety Board recording more than 100 injuries and dozens of deaths in just over a decade on domestic flights, although fatalities have mostly occurred when turbulence has caused the planes to crash. On bigger planes, turbulence risks head or other injuries to people who could be thrown around the cabin if not strapped in, or be struck by flying debris – not least during a trolley service. Crew are at particular risk and have the biggest number of injuries. Broadly, it is caused by the meeting of air at different temperatures, pressure or velocity, where different wind patterns collide – a bit like...