President Obama, appearing emboldened after his recent move to cut carbon emissions from coal-fired power plants, on Saturday ridiculed members of Congress who deny climate change or plead scientific ignorance as an alibi for avoiding an inconvenient truth. Speaking in gleefully sarcastic terms to a commencement ceremony at the University of California, Irvine, Mr. Obama likened those who deny climate change to people who would have told John F. Kennedy, at the dawn of the space program, that the moon “was made of cheese.” He saved his most scathing words for lawmakers who say they are not qualified to judge...