Light emitted from urban areas in the world, c 2005.
© National Aeronautics & Space Administration / Science & Society
As the world has undergone a steady process of urbanisation, scientists are becoming more concerned about the long-term effects. Unlike rural communities, urban sprawl completely transforms the landscape and the soil and alters the surrounding ecosystem and the climate. Marc Imhoff, a biologist at NASA's Goddard Space Flight Centre, and a team of researchers have been looking for ways to measure the effects of urbanisation on the biological productivity in the United States and other countries around the world. The researchers created a method of mapping urbanisation on a countrywide scale by using satellite images of the light cities generate at night. With the resulting city lights maps, they are now zeroing in on the impacts urban sprawl has on the food we eat, the air we breathe, and the ecosystem within which we live.