The Advertising Standards Authority has put tighter policing of claims to be "carbon neutral" or "net zero" on the table after finding that consumers were unsure of their exact meaning.
Before taking this step, it is first updating its guidance for advertisers on how to ensure such claims are responsible and will then monitor their usage in advertising over a six-month period.
The new guidance is expected to arrive before the end of the year and to require advertisers to adequately explain the basis on which they make such claims, even where such advertising is constrained by space or time.
Should the ASA decide from its monitoring that the evidence for claims is questionable, it will launch a review aimed at providing further guidance about what forms of evidence are more or less likely to be acceptable.
The watchdog revealed the plan alongside research into consumer understanding of the two terms and language in the electric and hybrid car market.
The research found participants tended to believe that "carbon neutral" claims implied that an absolute reduction in carbon emissions had taken place or would take place, and when the potential role of offsetting in achieving carbon neutrality was revealed, this could result in consumers feeling that they had been misled.
Claims in air travel, energy and automotive advertising tended to attract more attention, and the potential role of offsetting, when revealed, could result in greater disappointment. Participants suggested the need for transparency is potentially greater in those sectors.
The programme of work is part of the review of the ASA’s regulation of environmental issues in advertising that it began last year.
The review has already produced new rules aimed at preventing "greenwashing" campaigns, with HSBC yesterday (19 October) becoming the latest brand to be found in breach. Two poster ads by Grey were ruled to have given consumers the misleading impression that HSBC was making, or intended to make, a positive overall environmental impact.
Earlier this year an Innocent Drinks ad by Mother London was similarly banned for misleadingly associating the brand with a positive impact on the environment, after 26 complaints.
In its response to the complaints Innocent highlighted the opening of a carbon-neutral factory among the actions it was taking to reduce its environmental impact.