Andrew McAfee, co-director of the MIT Initiative on the Digital Economy, explains how the U.S. economy is growing and actually using less and less stuff to do so. Thanks to new technologies, many advanced economies are reducing their use of timber, metals, fertilizer, and other resources. McAfee says this dematerialization trend is spreading to other parts of the globe. While it’s not happening fast enough to stop climate change, he believes it offers some hope for environmental protection when combined with effective public policy. McAfee is the author of the book “More from Less: The Surprising Story of How We Learned to Prosper Using Fewer Resources—and What Happens Next.”