Texas Republican Representative Lamar Smith

FREDERICKSBURG, Texas—It’s midway through fall, and cold has yet to settle over the Eckhardt family orchard. So, Diane Eckhardt waits with rising apprehension.

Cold is the switch that triggers the growing sequence that by summer has limbs sagging with ripe, juicy peaches. The reliable chill season in Texas Hill Country allowed Eckhardt’s grandfather, Otto, to start the family business here in the 1930s.

But last year, with temperatures the warmest since 1939, Eckhardt’s trees produced just 10 percent of their usual yield. And the year before, warm weather reduced production between 60 and 70 percent. Now, Eckhardt worries not only about the next crop, but about the future of a business she hopes will be passed on to her niece and nephews.

“We know climate change is happening,” she said.

But while the Eckhardts face that certainty, their congressman sows uncertainty, casting doubt on the consensus science that greenhouse gases are the dominant cause of rising global temperatures, and opposing government action to curb them.

Sixteen-term Republican Lamar Smith has used his […]