In the EU, the answer may soon be health warnings, as explained by this article from Leigh Phillips at EUobserver:

Europe’s media giants have attacked proposals to slap environmental cigarette-packaging-style ‘health warnings’ on car advertising in newspapers and magazine.

The European Publishers’ Council, which represents major publishers and broadcasters across the continent, have warned that such advertising regulations, if adopted, threaten the freedom of the press.

“A state-imposed mandate on car advertising would pose a major threat to free competition and journalism,” said EPC chairperson Francisco Pinto Balsemao in a statement.

“Advertising is vital to maintaining a vibrant, independent and diverse media landscape in Europe and car advertising accounts for up to 20 percent of advertising revenues,” he added.

The media owners are worried that environment commissioner Stavros Dimas is set to announce proposals that would require all car adverts in newspapers and magazines, and possibly on TV and radio to include CO2 ‘health warnings’, so called due to the concept’s similarity to the health warnings on packages of cigarettes.

If adopted, says the EPC, the health warnings will lead to car companies taking their advertising elsewhere – to sporting events or concerts, as cigarette companies did when print advertising restrictions were imposed on the tobacco industry in the 1990s.

“An independent, free media cannot survive to inform and educate if it is not adequately funded.”

Specifically, the EPC fears that in an expected revision of a 1999 directive requiring car adverts to contain information for consumers on fuel efficiency and CO2 emissions, the commission will adopt proposals in line with those suggested in a report from UK Liberal MEP Chris Davies published in December 2007.

These suggested car companies should devote a full 20 percent of any car advertisement to these environmental warnings.

Currently under discussion, the new rules are expected to be unveiled by the commission by the end of the month.

The commission has opted to move on car advertising following almost a decade in which manufacturers have widely flouted the 1999 directive, which required that adverts include information that is “easily legible and no less pronounced than the main part of the advertising message” and “easily understood, even when read briefly.”

But in many cases the environmental information stretches only a few millimetres high and is barely legible.

The EPC says that because “more and more [low-emission, fuel-efficient] cars are produced and marketed, so there is no need for the regulators to step in.”

“Commercial advertising should never be hi-jacked by regulators to impart specific technical information that they want to distribute in neat formulaic ways,” added EPC executive director Angela Mills Wade.

“Quite simply it doesn’t work and do so is an abuse of freedom of commercial speech.”

Jeroen Verhoeven, a car efficiency campaigner with Friends of the Earth Europe, rubbished the suggestion that the warnings would be an attack on freedom of the press or speech.

“Advertising is a very important tool for car manufacturers in convincing people to buy their products. And it is the case that the more fuel-consumptive cars are marketed more.”

“If news articles about emissions were more important than adverts, why would these companies spend so much on advertising?”