December 9, 2005

End of Sahel Drought May Mean More U.S. Hurricanes

By Daniel Flynn

DAKAR -- Signs a three-decade long drought in Africa's arid Sahel belt may be ending could herald an increase in hurricanes battering the eastern seaboard of the United States, a leading climatologist in West Africa said.

Hurricanes which pummel the Caribbean and the Gulf of Mexico each year often start their lives thousands of kilometres to the east as black storm clouds which cross the Sahel from the mountains of Chad or Sudan.

"Many of the hurricanes which reach Florida or the United States are formed here," said Amadou Gaye, head of Dakar University's Atmospheric Physics Laboratory.

"Squalls from the Sahel reach the African coast, where some of them become whirlwinds and perhaps 10 days later they become cyclones in the Atlantic," he told Reuters in an interview on Thursday.

The Sahel, a semi-desert zone which separates the Sahara from Africa's more tropical regions around the Equator, has been gripped by the worst drought in modern history since the 1970s.

But that appears to be changing. The heaviest rainfall in some thirty years in mainland Africa's most westerly country, Senegal, coincided with a record hurricane season this year -- including Hurricane Katrina, which devastated New Orleans.

"Since 2000, there has been an upward tendency in rainfall," Gaye said. "Statistically, when there is a very rainy year in the Sahel there are a lot of Atlantic hurricanes."

Lines of towering Cumulonimbus storm clouds reaching up to 12 kilometres (8 miles) into the atmosphere, which cross the Sahel from west to east, are the region's main source of rain.

"These lines of squalls are the motor of the Sahel's climate," said Gaye.

Largely populated by nomadic peoples such as the Berbers and Tuaregs, the Sahel was relatively green during the 1940s through to the 1960s but since then rainfall has plunged.

While data suggests that rainfall over the Sahel appears to be rising in recent years, it remains premature to herald the end of the drought, Gaye said.

"Overall, rainfall still remains lower than in the 1950s. But if the trend continues for five years, people will say the drought is over."

The prolonged drought in the Sahel -- which includes Senegal, Mauritania, Mali, Burkina Faso, Niger, Nigeria and Chad -- has impoverished many farmers and forced people off the land.

Niger experienced severe food shortages this year, brought on by poor rains and locust swarms that underscored the region's vulnerability.