This month, in the U.K., a national smoking ban came into effect. Smokers all over the country vacated comfortable, warm armchairs in pubs and restaurants and retired to picnic tables, beer gardens, and terraces.

But while paternalists celebrated a triumph for public health, environmentalists mourned a tragedy for the Earth. As it turns out, when smoking is not allowed in heated, enclosed areas, businesses invest in heating the great outdoors for their puffing patrons. Gas-guzzling patio heater use is predicted to double in the UK, increasing CO2 emissions (perhaps by 20,000 tons a year just for London) and breeding mosquitoes.

Patio heaters can use as much gas in six months as the average U.K. stove does in a year. They’re therefore fairly expensive to run. But the smoking ban has made outdoor heating more profitable than ever before, particularly since only some venues can afford them or have any outdoor space. The heaters become a draw for smokers and their friends.

Both London Mayor Ken Livingstone and Norman Baker, a U.K. Liberal Democrat Party MP, have spoken out against patio heaters. Baker claims that "patio heaters are an absurd invention. It is ludicrous that people are trying to heat the open air, as well as being irresponsible in the light of the climate change challenge we face.” He says that instead of relying on such ridiculous modern technology, people should just put on more clothes if they’re cold.

And if they refuse to wrap up, the only solution is another ban--this time on patio heaters.