The bosses of the AA, IPA and ISBA say tracking carbon impact is vital but argue Purpose Disruptors' methodology is flawed because it overstates the emissions attributable to advertising.
The Swedish oat-drink company has added information about its climate impact to products in the U.S.
Clients will be advised on which channels, and eventually media vendors, are causing the most carbon emissions in effort to slash advertising's carbon footprint.
UK initiative sees brands paying a green levy of 0.25% of the cost to produce an ad.
Company is partnering with Conservation International and WWF.
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