ive of the ten March days I was in Mali, I never saw the sun. It was blotted out by an epic dust cloud that spread hundreds of miles in every direction, borne by the harmattan, the southwesterly gale that blows down from the Sahara during the dry season. Dust storms have always been a part of life here. They can be so thick you can't even see your hand.
Historically, the harmattan blows from December through February. But since 1968, Mali and the rest of the Sahel ("shore" in Arabic, the semi-arid band below the Sahara that stretches from Senegal to Eritrea) have experienced a devastating drought. Precipitation has dropped 30 percent -- the most dramatic decline ever recorded -- and the rainy season has been truncated to two months, July and August.
At the same time, the population of the Sahel has exploded, compounding the demand for firewood, the main source of cooking fuel. A million acres of trees a year are being cleared and burned in Mali alone, a landlocked country nearly twice the size of Texas whose top two-thirds -- from Timbuktu north -- are in the Sahara, and whose bottom third is in the Sahel.
The drought, amplified by the deforestation, has brought catastrophic desertification to the Sahel. Dust storms pick up two billion to three billion tons of Sahara dust a year. The finest red particles are whipped up into the upper atmosphere, to 12,000 feet and higher, and are transported across oceans by the trade winds. Sahara dust lands on cars in Florida and South Texas. In February 2005 the sun was blotted out in Austria. In May a "blood rain" fell in England. NASA satellite photographs have shown clouds -- one larger than Spain -- off the coast of Morocco. Sahara dust travels to Toronto and Greenland. It is snuffing coral reefs and sea urchins in the Caribbean. So the Sahel's desertification is not just a matter of local concern.
During the first five years of the drought, 250,000 people and 3.5 million head of cattle in the Sahel died. In the mid-1980s, rural Mali again became uninhabitable, and many of the villages, where three-quarters of the population live, were abandoned. Most of the environmental refugees poured into Bamako, the capital, whose population has grown from 800,000 to two million in the past 20 years.
In 2003, good rains fell, and 2004 was also a relatively wet year. But the rains triggered the emergence of billions of pink locusts, which skeletonized whatever vegetation they landed on. In Niger, to the east, where the rural population was already on the edge after three decades of drought, the scourge last summer helped produce a famine of Ethiopian direness. In 2005, the rains were also good, but there were still those epic dust storms before they came. The drought may have subsided for now, but most scientists agree that the processes that are desertifying the Sahel are continuing.