Lake Chad, shown at the top-center of this true-color MODIS image acquired on October 21, 2001, is but a fraction of what it once was. The lake, surrounded by wetlands, has been taxed heavily as a source for numerous irrigation projects, and is subject to an arid climate that has endured a dramatic decrease in rainfall over the past forty years. The green and brown rippled area to the north and northwest of the lake (most clearly visible in the high-resolution image) suggests the lake's previous surface area.
The majority of the lake sits in the country of Chad, which spans from top to bottom on the right side of the image. The other countries visible, moving clockwise from Chad, are Cameroon, Nigeria, and Niger.
The top photograph was taken by Apollo-7 crew in October 1968 during a mission to test control of a spacecraft moving into different orbits. Based on photographs from Gemini and Apollo, the estimated open water area of Lake Chad was over 22,000 km² (Mohler et al. 1989, Lullaet et al. 1991). Although not known at the time, Lake Chad would not be observed this full again from orbit—it had significantly decreased in area when it was observed by Landsat in 1972. Space Shuttle crews have continued to photograph dramatic fluctuations in Lake Chad. A sampling of this time series from 1982-2000 is shown below the Apollo image.