Roth: Pope Francis was a climate hero. Trump reign gives his words extra meaning.

Donald Trump announced his first run for president on June 16, 2015. He lashed out against Mexican immigrants, environmentalists and other supposed enemies foreign and domestic.

Two days later, Pope Francis clapped back.

Francis’ landmark climate change encyclical, “Laudato Si: On Care for Our Common Home,” wasn’t meant as a response to Trump. But the 184-page teaching served as a powerful call to action. Francis preached urgency and compassion. He asked the world’s 1.3 billion Catholics...