The more you fly, the more perks you get: upgrades to a better cabin, access to an all-you-can-eat lounge, and priority boarding, among other things. And, of course, the option to accumulate “air miles” and fly again—for free.

A new report, commissioned by the UK’s Committee on Climate Change, would turn this process on its head. “Frequent flyer reward schemes that stimulate demand” would be axed. Instead, an “escalating air miles levy” would mean that people who flew the furthest would always pay the most.

The system, proposed by Imperial College London researcher Richard Carmichael, would add up the miles traveled by an individual for leisure over a roughly three-year period and apply increasingly severe taxes the more they flew. Long-haul flights would be penalized in particular, while travelers in business or first class would pay more to factor in their greater emissions. (Business travel, which makes up about 19% of all flights, would be subject to a separate scheme to “avoid loopholes or gaming the system.”)

For most people, this would have no meaningful effect. Families could still take an annual summer holiday to somewhere relatively nearby without incurring big extra costs. But for some jetsetters, the punitive taxation might be enough to curb their flying altogether. Those who could afford it, meanwhile, would pay for their choices—and help fund better rail or research into greener forms of air transport and alternative methods of travel.

At the moment, the aviation sector is strikingly undertaxed. Jet fuel is subject to very few levies, due to a 1944 global agreement (paywall). While Carmichael supports imposing taxes on jet fuel too, he notes that this would penalize all travelers by the same amount. Introducing the frequent-flyer levy would target the roughly 15% of the UK’s population responsible for 70% of flights. “Given the scope for frequent flyers to have carbon footprints many times that of the average UK household, a lack of policy in this area is likely to be increasingly seen as inconsistent and unjust,” Carmichael writes. Maintaining the UK’s high public engagement with climate action means making sure emissions are shared equally.

Encouraging people to vacation locally, and avoid circumnavigating the globe, would indeed be good news for the planet. But it might have damaging consequences for countries that rely on British tourists. In the Maldives, for instance, tourism makes up nearly 40% of GDP, with Brits accounting for nearly a tenth of all travelers last year. Of the 25 countries that derive the largest share of their income from tourism, only three—Malta, Iceland, and Croatia—are within a few hours’ flight of the UK.