By 2050, 80 percent of the world’s population will live in cities. That means these urban centers will carry the burden of climate change, income inequality and other side effects of a growing population. This hour, we’ll talk about how cities can answer these challenges with Jonathan Rose, author of “The Well-Tempered City: What Modern Science, Ancient Civilizations, and Human Nature Teach Us About the Future of Urban Life” (Harper Wave). He’s in town for an event tonight at the Dallas Institute for Humanities and Culture, and he’s the keynote speaker at the Urban Land Institute national convention at the Hutchison Convention Center.