Why Those Bank Emissions Numbers Are So Rosy

On the surface, Deutsche Bank AG, Citigroup Inc. and Mizuho Financial Group Inc.all appear to be delivering on their promises to cut carbon emissions.

The three banks (along with most of their peers) have committed to eliminating financed emissions—the greenhouse gas-pollution enabled by their lending and investing—starting with the most carbon-intensive areas of their balance sheets. And in sustainability reports published this year, all three banks said those numbers had come down—in some cases significantly.

Yet if you read the footnotes, one would discover that their emissions have fallen in large part due to technical factors outside ...