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Thursday, 18 November, 1999, 21:34 GMT
'Nature caused Sahel drought'


By BBC Science's Toby Murcott

A massive drought that struck parts of Northern Africa in the 1970s and 80s may have been the result of a natural climate cycle.

Up to now, many scientists thought the drought in the Sahel zone was caused by humans over-using natural resources in the region.

But a new study in the journal Science shows how a combination of ocean temperature and loss of natural vegetation could have been the sole reasons for the drought.

The drought pushed the Sahara desert south, destroying farmland. It had a major impact on many countries including Nigeria, Niger and Mali.

Now, scientists from the Nasa Goddard Space Flight Centre and the University of California in Los Angeles believe it could all be explained by natural phenomena.

Computer simulation

The researchers produced a computer model that included ocean surface temperature, the amount of moisture in the soil, and loss of vegetation.

With all those conditions, the computer model behaved just like the Sahel drought - producing a long period of dry, cool weather.

It appears that human activity might not have been to blame for the drought, and the study suggests the Sahel region may be naturally prone to such large climate changes.

The challenge now is whether that information will help scientists predict when the next drought is likely to occur.


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See also:
18 Nov 99 |  Sci/Tech
Climate change warning
30 Nov 98 |  Africa
Fighting back the widening deserts

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