Tens of millions of commuters descend into the bowels of the Earth each day to ride subways in the United States and China, each passing countless advertisements on the underground walls. But while billions are spent on commercial ads asking commuters to become middle-class consumers of goods produced around the globe, "virtually no public service advertisements tell us to conserve like global citizen," writes Steven Lewis, C.V. Starr Transnational China Fellow, in a recent commentary for China Daily USA.

Public service ads (PSA) are a critical first step to presenting global problems - such as overuse of antibiotics, pollution, extinction of species and destruction of precious resources - as more than mere local issues, says Lewis, who studies the influence of advertisements in China. Chinese and U.S. government leaders should "begin discussions on how we can share PSAs in our cities and begin to create the public idea of working together to solve shared global problems. We cannot just shop together; we have to save together as well."

Read "The mixed message of global advertising" by Steven Lewis in the Sept. 7, 2012, China Daily USA.