When you’re in a city, it can feel as if you’re at the center of the world. In reality, 98 percent of the earth’s surface is rural, wild, remote—essentially countryside. How will radical climate and environmental changes in these vast expanses and specialized ecosystems affect life in cities and life on earth? In “Countryside, The Future,” the pioneering architect and urbanist Rem Koolhaas works with Samir Bantal, director of AMO, the think tank of the Office for Metropolitan Architecture, to project new realities. —E.C.