Reaping What We Sow: Mapping the Urbanization of Farmland Using Satellites and City Lights

This page contains archived content and is no longer being updated. At the time of publication, it represented the best available science.

	Saving What We’ve Got Before It’s Gone
	What does all this mean for the U. S.? For now, Imhoff believes that the United States still has plenty of good soil and that we are not going to run out of food anytime soon if we work to curb our urban sprawl. However, in other countries there is possibly more to worry about in the near future. "We did a similar study in China," says Imhoff. "In China, they’re also having the same trends. The best soils are being developed now with their increased economic development. But they have fewer soils to rely on." Probably the worst-case scenario is in Egypt. They have very little arable land and it is all along the Nile Delta where everybody lives. As the population in Egypt expands, people either have the choice of building on prime farmland or of moving out onto very inhospitable areas of the Sahara.
	In order for the world to save its farmlands for future use as the population expands, Imhoff feels that city planners need to start building and developing city infrastructure on rocky, non-level, and arid soils. "I think that land use planning has to have some teeth. We need to leave the land that is productive in agricultural use," he says. Until then the Goddard team will continue to monitor the U.S. as well as other countries and alert people to this problem before we get to the point where we have plenty of big lawns and convenience stores, but very little food.		A photograph of Cairo, Egypt, taken from the space shuttle. Located at the southern end of the Nile Delta, Cairo is one of the world’s fastest growing cities. It is also located on what was once prime farmland. Grey urbanized areas are continually eating into the green cropland along the Nile River—Egypt’s only arable land. (Photograph courtesy NASA Johnson Space Center Astronaut Photography)
	References Imhoff, M. L., W. Lawrence, and C. J. Tucker, 2000: The Impact of Urban Sprawl on Photosynthetic Production in the United States, presented at 2000 American Association for the Advancement of Science (AAAS) Annual Meeting, pp. 1-3. World Resources Institute, 1996: World Resources 1996-97, Washington, DC. Related Links Assessing the Impact of Urban Sprawl on Soil Resources in the United States Using Nighttime "City Lights" Satellite Images and Digital Soils Maps Defense Meteorological Satellite Program A Bumper Crop of Brand New Homes		Among the soil types shown, only “fluvisols” are suitable for farming. Fluvisols are soils deposited by flowing water, specifically the rich silt laid down by the Nile River’s annual flooding. Other soils in Egypt are too dry, too salty, or too rocky for farming. (Image courtesy Marc Imhoff, NASA GSFC)

Subscribe