Randy Newman captured a moment of national anger in “Burn On,” a song about the polluted Cuyahoga River catching fire in 1969. That environmental disaster pushed Congress and the Nixon administration to create the Environmental Protection Agency and pass laws like the Clean Water Act and the Safe Drinking Water Act. But today’s guest warns that these laws are woefully outdated, and that clean water is becoming increasingly scarce. Access to freshwater, he argues, is the most urgent problem we face in the twenty-first century. Alex Prud’homme is the author of “The Ripple Effect.” He joins us in the studio.