Big business sees the promise of clean energy

PITY America’s big businesses. For years their efforts to reduce their carbon footprint were dismissed by environmentalists as “greenwashing”. Now, after months trying to persuade a supposedly pro-business new president, Donald Trump, of the merits of staying in the Paris climate accord, he practically laughed in their faces by withdrawing on June 1st.

Executives fear the exit will do no good to America’s—and by implication their—reputation. Not for nothing have more than 900 American firms and investors, including Amazon, Twitter, Target and Nike, put their names this week to a “We are still in” open letter to the UN. Its signatories pledge to help reduce the country’s carbon emissions by 26% by 2025, in keeping with America’s Paris pledge. That may be quixotic but is a rallying cry nonetheless.

Indeed, some American firms are taking climate change so seriously that they are surprising even former critics. Alongside energy-efficiency measures, the strongest evidence...