In an otherwise useful reminder of why the much-ballyhooed “transition” to unconventional energy won’t happen anytime soon—because the massive attendant costs can’t be borne by most of the world’s people confronted by the difficult realities of eking out a living—Bjorn Lomborg (“When the Only Problem Was Climate,” op-ed, May 9) nonetheless tries to have it both ways. He argues that the world should “ramp up investments in green innovation, eventually driving the cost of clean energy below that of fossil fuels.”

Why, without massive subsidies, does the private sector fail to invest in such innovation in pursuit of a competitive advantage? Answer: The unconcentrated energy content of wind flows, sunlight and other green fantasies means that it is very unlikely that their costs ever will fall below those of fossil fuels, which are also likely to enjoy the benefits of innovation. Further, it is misleading to describe unconventional energy as “clean,” shunting aside the heavy metal pollution, wildlife destruction and myriad other environmental problems caused by such energy.

Benjamin Zycher

American Enterprise Institute

Long, Beach, Wash.

Read the full exchange in the Wall Street Journal.