I’ve landed in Aspen just in time to hear Dr. Peter Gleick and his Big Idea at the opening ceremonies of the third annual Aspen Ideas Festival. “Maybe less is better,” Gleick declared to the audience gathered this afternoon in the Greenwald Pavilion. The world should be prepared for shifts in economies, scale and living “within fixed limits.” This will be “a different challenge for a lot of us” as growth-based economies are no longer supported by massive population increases and are no longer sustainable. It’s a big idea that we haven’t quite got our arms around yet — one that has massive implications, and one that’s antithetical to a seemingly infinite mode of environmental and economic Manifest Destiny. It comes down to defining and embracing what’s “sustainable” on our little blue dot.