Download the PDF In measuring carbon emissions, it's easy to confuse morality and science.
by Michael Specter

A little more than a year ago, Sir Terry Leahy, who is the chief executive of the Tesco chain of supermarkets, Britain’s largest retailer, delivered a speech to a group called the Forum for the Future, about the implications of climate change. Leahy had never before addressed the issue in public, but his remarks left little doubt that he recognized the magnitude of the problem. “I am not a scientist,” he said. “But I listen when the scientists say that, if we fail to mitigate climate change, the environmental, social, and economic consequences will be stark and severe. . . . There comes a moment when it is clear what you must do. I am determined that Tesco should be a leader in helping to create a low-carbon economy. Read more »