Urbanization – "Now we know that cities across the globe—particularly in Sub-Saharan Africa, South Asia and East Asia—are growing fast at an unprecedented scale. Most growth will be in small- and medium-sized cities. Projections range, but most estimate an increase from about 3.5 billion urbanites today to about 4.3 billion in 2025 (Hoornweg and Bhada-Tata, 2012) to 5.6 billion by 2040 (Shell Scenarios, 2013). We also know that demand for resources and services is going to balloon— McKinsey estimates that there will be about 600 million new middle class consumers in emerging market cities by 2025. These folks—roughly totaling the current combined population of the US, Brazil, and Mexico—are going to want more cars, air conditioners, rib-eye steaks, tuna tartar, trips to the Great Barrier Reef and Glacier National Park, and all the other fine things that wealth brings. Who blames them? I sure don’t." Ackn. WB.org