Since the 20th celebration of the Earth Summit, which was held in Rio de Janeiro in 1992, many journals, disciplines, and people are reflecting on the progress towards sustainable development in the last two decades. Although there has been progress on many fronts, the threats to global sustainability are large and growing. Some liken the world situation to walking north on a southbound train, meaning that although we are making progress technologically and in small pockets around the world, the world's ecosystems are degrading, the world is far from equitable, and the gap between the 'haves' and the 'have-nots' is growing. Environmental, social, and economic sustainability still seems distant.