There is a growing public backlash against hollow claims about corporate green credentials.
A recent survey by Getty Images showed a sharp rise in the use of advertising images such as polar bears on melting ice caps or city skylines under water. There has even been a surge in 'greenwashing' - literally the use of green tones in adverts and packaging to suggest environmental credibility.
A poll last year by Chatsworth showed only one per cent of opinion formers believed UK companies had adopted green policies out of a genuine concern for the environment.
The San Francisco-based CorpWatch even awards bi-monthly Greenwash awards to 'corporations that put more money, time and energy into slick PR campaigns aimed at promoting their eco-friendly images, than they do into actually protecting the environment'.
One of their recent nominees was General Motors, for an advert featuring a Saturn SUV (Chelsea tractor to you and me) on a polar ice floe being gazed at by a whale. That's not to say that all misleading claims are malicious. Some are hard to prove and on issues such as carbon-offsetting, there are conflicting opinions even among experts. 'Obvious' claims can be too simplistic.
For example, people often assume that buying food from abroad is worse than buying local. But it is not as simple as that. Studies have shown that Dutch-grown roses, for example, can use more energy to produce than Kenyan roses.
Organisations are on the whole taking sustainability seriously. But in their enthusiasm, they can make mistakes or over-claim - and PR practitioners are in the front line.
That's why the CIPR has produced a set of guidelines on how companies should report on their environmental impact. Launched last week, the guidelines - available from the CIPR website (www.cipr.co.uk) - look at the pitfalls that can lead to businesses being accused of greenwash.
So there is no excuse. Let's start cutting out the hot air.
Paul Mylrea is director of communications at the Department for International Development.