Along with skinny ties and office misogyny, something that may have struck viewers of Mad Men’s fifth season was a particularly accurate detail of American life in the ’60s: raging air pollution. Toxic smog smothered Los Angeles on many days, and it killed hundreds in New York City. In 1970, the federal government responded with an updated Clean Air Act, and by creating the Environmental Protection Agency and empowering it to regulate air pollution. Smog is down by one-third since 1980, and the pollutants lead and nitrogen dioxide have been cut by 98 percent and 60 percent, respectively. We’re breathing cleaner air, so there’s good reason to assume EPA regulation can mitigate the equally deadly threat of climate change. President Obama has begun that process with the Clean Power Plan to reduce carbon emissions from coal-fired power plants—if legal challenges to it fail, which will depend on the outcome of this year’s election and the appointment of a new Supreme Court justice—and establish higher fuel-economy standards for cars and trucks. Hopefully, in 40 years, our kids will be as baffled by today’s threats of climate change as we were by the two-martini lunch.