2 . Twenty-four trains, nine countries, 13, 500 miles. They are the numbers behind the heroic round trip one man took from Southampton in the UK to eastern China.

Roger Tyers, 37, used over $2, 500, which was almost twice more than the cost of a return flight, to travel to the Chinese port city Ningbo for academic research in May, 2019. The man spent a month on board 15 trains during the first leg of his round trip. It was the climate crisis, not a love of trains, that drove the sociologist to choose this complicated route over a return flight. He stopped flying when UN climate experts warned that the world had less than 11 years to avoid terrible levels of global warming. Tyers calculated that his train journey to China produced almost 90% less emissions than a return flight.

Tyers is not the only person to avoid air travel in response to climate change. Thousands of people worldwide have publicly promised to stop flying. Activist Maja Rosen launched the “Flight Free” campaign in Sweden with the goal of encouraging 100,000 people not to fly for one year. Although only around 14,000 people signed the online “#flightfree2019” pledge (保证), Rosen, who stopped flying 12 years ago, says that the campaign had made more people worry about the climate crisis and aware of harm of travel by air and motivated them to try new ways of travelling.

According to a survey released in May 2019 by Swedish Railways (SJ), 37% of respondents chose to travel by train instead of by plane where possible, compared to 20% at the start of 2018. An SJ spokesperson said: “Rail travel has been augmented due to the worries.” Domestic passenger numbers in July fell by 12% compared to the previous year, according to Swedavia, a company which operates Sweden’s 10 busiest Airports.

“The collective pledge helps fight the sense of hopelessness many people feel when it comes to tackling climate change”, Rosen said. “One of the problems is that people feel there’s no point in what you do as an individual. The campaign is about making people aware that if we do this together, we can actually bring changes.”