Cities can reduce the impact that an individual has on the environment by increasing the density and efficiency of human settlement, yet the cities themselves pave over nature. By 2030, hundreds of millions more people will live in cities around the world creating vast mega-metropolises and blotting out ecosystems.
The area covered by cities may sprawl out over an additional 1.2 million square kilometers by 2030, according to a study published in the Proceedings of the National Academy of Science. That means the area covered by cities may triple.
Much of the expansion will occur near cities that are already behemoths, but some biodiversity hotspots are in danger of being swallowed by the gray monotony of cities and slums. In particular, the urbanization of the tropical Guinean forests of West Africa may devour 6.8 percent of the regions' hotspot. The western Ghats region of India, the highland forests of eastern Africa, and the ecosystem of Sri Lanka are other hotspots that are likely to lose ground.
The study used satellite data and population growth forecasts to make its estimation. What the estimates can't see is how those future cities will be constructed. Study author Karen Seto of Yale University told Nature News that the sprawl forecast for 2030 could help city planners make wise choices in how they build their booming cities.
"Once roads are in place, sewers are in place, it's really difficult to re-do how a city looks," Seto said.
Beijing central business district skyline at night. (Scott Meltzer, Wikimedia Commons)