Growth of Urban Areas Poses Long-Term Threats, Study Says

A new study says the explosive growth of urban areas worldwide over the next two decades poses significant risks to human populations and the global environment, from the loss of agricultural land and wildlife habitat to increased vulnerability to the effects of climate change. Using satellite data on urban growth, the study calculates that the world’s total urban area quadrupled in size from 1970 to 2000 — an increase of about 22,400 square miles. By 2030, that urban footprint will expand by another 590,000 square miles to accommodate the more than 1.47 billion additional people expected to be living in the world’s cities, according to the study, conducted by researchers from four U.S universities — Yale, Arizona State, Texas A&M, and Stanford. “[Cities are] going to be growing and expanding into forests, biological hotspots, savannas, coastlines — sensitive and vulnerable places,” said Karen Seto, an associate professor of urban development at the Yale School of Forestry & Environmental Studies and lead author of the study, published in the online journal PLoS ONE.