Climate change poses two distinct risks for investors, and a special one for fund managers. The pledge last week by Larry Fink, CEO of fund giant BlackRock Inc., to push clients toward environmental, social and governance investing highlights another risk: that markets are shifting from harnessing the wisdom of crowds to the wisdom of a handful of powerful money-management executives. Leave the pros and cons of ESG aside for a moment. Whatever you think of Mr. Fink’s view, his letter highlights the power he wields over the direction of corporate America, thanks to the votes of BlackRock’s extensive holdings. Shareholders...