More than half of the 27 million carbon credits produced by one of the world’s largest offsetting projects did not correspond to actual emission reductions, leading carbon registry Verra has said following a two-year review of Zimbabwe’s Kariba forest protection initiative. Dozens of big companies, including Gucci, Volkswagen, Nestlé and Dutch electricity firm Greenchoice, bought millions of Kariba’s credits and used them to offset part of their own emissions and back up various green assertions. Nearly two years later, Verra announced last week that its review had found 57% of Kariba’s nearly 27 million credits were issued “in excess”. Questions over permanenceCMW’s Crook also raised concerns over the future integrity of the remaining 11.6 million Kariba credits deemed by Verra’s review to be of good quality. More than 5 million credits from the Kariba project had been kept in a so-called buffer pool, an insurance fund with credits set aside for unexpected losses in stored carbon.