There is an environmental problem that is just beginning to be recognized as being of global significance: "'Toyota-ization'".

The surfaces of deserts are being broken up by four-wheel drive vehicles such as the Toyota Land Cruiser, the Japanese version of the Land Rover and a great favorite with drivers in the Sahel, the dry states to the south of the Sahara, as well as many other challenging places.

The surface disturbance is proceeding at such a rate in Africa, the Middle East and Asia that it is contributing substantially to a rise in dust storms, and to an increase in dust in the global atmosphere generally, which could have serious climatic and health repercussions. Andrew Goudie, the professor of geography at Oxford University, told the International Geographical Congress in Glasgow that annual dust production in some parts of north Africa had increased ten-fold in the past 50 years, and that across the Sahel, from the Sudan to the Gulf of Guinea, it had increased six-fold since the 1960s.

Global dust emissions were between two and three billion tons a year, and this was even being felt in Britain, Professor Goudie said, with an increase in episodes of "blood rain" - the deposition of dust from the Sahara on the British land mass. "The world is getting a lot dustier," he said. The reasons included land use changes caused by growing populations, such as deforestation and overgrazing, but 'Toyota-ization', a word coined by him to mean disturbance by 4x4s, was a specific cause, the professor said.

"If you take almost any desert now, people go all over it in four-wheel drives," he said. "The number of four-wheel drives in the south-west US and indeed in the Middle East is staggering.

"The desert surfaces have been stable for thousands of years because they usually have a thin layer of lichen or algae, or gravel from which the fine sand has blown away. Once these surfaces are breached you get down to the fine sand again, which can be picked up by the wind."

The effect was particularly bad near cities. "If you take a city like Nouakchott, the capital of Mauritania, there are tracks leading out across the desert in all directions," he said.

Sand is often carried by the wind at the base of the storm. A typical storm could move on a front 100 kilometers or more across, and contain 30 to 40 million tons of dust. It was possible that disease-causing organisms - such as those responsible for foot-and-mouth disease - could be transported with it, the professor said.

© Copyright 2004 Independent Digital (UK) Ltd

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