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SHADOW OF A LAKE: AFRICA'S DISAPPEARING LAKE CHAD
Lake
Chad, once one of the African continent's largest bodies of
fresh water, has dramatically decreased in size due to climate
change and human demand for water. Once a great lake close
in surface area to North America's Lake Erie, Lake Chad is
now a ghost of its former self. According to a study by University
of Wisconsin- Madison researchers, working with NASA's Earth
Observing System program, the lake is now 1/20th of the size
it was 35 years ago.
Found at the intersection of four different countries in West
Africa (Chad, Niger, Nigeria and Cameroon,) Lake Chad has
been the source of water for massive irrigation projects.
In addition, the region has suffered from an increasingly
dry climate, experiencing a significant decline in rainfall
since the early 1960's.
LAKE
CHAD - 1973 AND 1987
Click
on the picture to enlarge image.
Click on the year to get a high resolution of the image.
The most dramatic
decrease in the size of the lake is shown in the fifteen years
between January 1973 and January 1987. Beginning in 1983 the
amount of water used for irrigation began to increase. Ultimately,
between 1983 and 1994, the amount of water diverted for purposes
of irrigation quadrupled from the amount used in the previous
25 years. The red color denotes vegetation on the lake bed
and the ripples on the western edge of the lake denote sand
dunes formed by the wind.
Click
here for a Quicktime movie of 15 years of changes in Lake
Chad.
LAKE
CHAD - 1963, 1973, 1987 AND 1997
Click
on each pic to enlarge. Click on the year to get a high
resolution of the image.
This additional
time lapse sequence shows Lake Chad shrinking ever smaller
over the course of four decades. The first image, taken with
the Argon satellite in October 1963, and three subsequent
Landsat satellite images taken in January 1973, January 1987,
and January 1997, show the progression of the lake as it shrinks.
Click
here for a Quicktime movie of four decades of change.
PRESENT
DAY LAKE CHAD
Click
on the picture to enlarge image.
Click on the title of the picture to get high resolution image.
Here,
a composite of Landsat-7 images from November 2000 to February
2001 shows the present stage of Lake Chad. The small patch
of blue that is now the lake stands in stark contrast to the
wide swath of the old lake bed (shown in green, indicating
vegetation.)
Click
here for a Quicktime movie of present day Lake Chad.
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