Why ‘Carbon Offsets’ Don’t Do All That They Promise

Procter & Gamble Co. plans to spend $100 million on carbon offsets to neutralize a small proportion of its greenhouse gas emissions. Another consumer products giant, Unilever Plc, is foregoing offsets, at least for now. Perhaps surprisingly, it’s Unilever’s course that’s more in line with the urgings of scientists and environmental activists. That’s because while offsets sound appealing and have drawn investments from companies including Disney, Lyft, Delta Airlines and Apple, there’s a fier