In mid-August, to uproar from the right-wing press, teen activist Greta Thunberg set sail in a zero-emissions yacht on a two-week trip across the Atlantic to reach the UN climate talks in New York. Taking her role as figurehead of the global school strikes for climate movement seriously, Greta shuns air travel for its high levels of emissions production, recently completing a tour around Europe entirely by train.

The problem Greta identifies is a real one. Flying is responsible for about 3.5 percent of global greenhouse gas emissions, and is often the cheapest and easiest option for domestic travel or short-haul to western Europe. But emissions aren’t limited to air travel. From planes to cars — which still dominate UK travel both locally and nationally — our most popular transport systems are largely carbon intensive, with one-third of the UK’s CO2 emissions coming from transport.

And it’s no wonder we choose these forms of transport compared to the alternatives. Public transport in the UK is expensive and inadequate. Rail fares will be hiked again in January, imposing a 2.8 percent increase on consumers and adding over £100 to many already extortionate annual season tickets. Despite paying five times as much of our salary in the UK on rail travel compared to our European neighbors, delays and overcrowding are common. In rural areas and even cities, limited bus routes cut in half by Tories since 2010 mean irregular services and many areas not connected at all. The crisis of rural public transport has left communities cut off from the rest of society, unable to access work and vital services.