ASA to ban ads making unproved eco claims

Adverts that claim products are carbon neutral using offsets are to be banned by the UK's advertising watchdog unless companies can prove they really work, the Guardian can reveal, as Gucci becomes the latest company to struggle with a high-profile environmental commitment based on offsetting.

- Patrick Greenfield, Jillian Ambrose, Ellen Ormesher

Amid growing concern that firms are misleading consumers about the environmental impact of their products, the Advertising Standards Authority (ASA) is to begin stricter enforcement over the use of terms such as "carbon neutral", "net zero" and "nature positive" as part of a greenwashing crackdown later this year after a sixmonth review.

Under the plans, the ASA will take action against firms that tell consumers they can buy their products without making global heating or nature loss worse by virtue of purchasing offsets- unless they can demonstrate they really are effective. The move follows recent enforcement by the ASA against Lufthansa and Etihad about green claims. Companies will still be allowed to talk about their sustainability efforts, the Guardian understands.

In January, a joint Guardian investigation found that many rainforest offsets certified by Verra, which operates the world's leading carbon standard, had little impact despite being widely used by major companies for environmental claims, also finding evidence of forced evictions at a flagship project in Peru used by Disney and Apple. The findings were strongly disputed by Verra.