The Senate rejected the Green New Deal on a 57-0 procedural vote last month. Not a single senator voted to bring the proposal to the floor, including its chief sponsor, Massachusetts Democratic Sen. Ed Markey. Climate alarmists demanded that Republicans come up with a plan of their own. But the best plan may be no plan at all, for at least four reasons.

First, cutting U.S. emissions won’t have much of an effect on the climate. According to the United Nations Environment Programme, total man-made emissions of carbon dioxide...