Delta Airlines Inc. has for the past few years been among the biggest corporate buyers of carbon offsets. That demand — from airlines, energy companies, automakers and logistics firms — drove forecasts of a market worth hundreds of billions of dollars in the coming years. But after strong pushback from experts, Delta is now among a growing list of major companies that have ended purchases of these cheap credits. Alphabet Inc.’s Google and EasyJet Plc have recently joined in the rejection of what had been an enormously popular approach to sustainability. Many of these companies are now focused on the more expensive task of reducing their own emissions. As a result, there’s been a sharp decline in sales in 2023, according to a Bloomberg Green analysis of the most recent public datasets covering 320,000 offset transactions. While the data don’t include every transaction, the sample covers the vast majority. It’s the second consecutive annual decline, pointing towards an emerging trend. Among the offset purchases seeing the steepest declines are credits tied to renewable-energy projects, which fell 29%. Most experts have written off these offsets as junk because electricity from wind, hydro and solar plants is already low cost. That suggests extra funding from the sale of the credits doesn’t contribute to further reduction in emissions. “For many years, scientific reports have repeatedly questioned the credibility of offsets from renewable-energy projects,” said Lambert Schneider, a carbon markets expert at the German research organization Öko-Institut. That scrutiny culminated over the summer with a decision by a crucial standard-setting organization to classify a large portion of carbon offsets as useless.<br/>