Monday, September 28, 2009


Griffith (Australie)

Riyadh (Arabie Saoudite)

village dans la région du Minqin (Chine)

Kaboul (Afghanistan)

Dérèglement climatique ou pas, ce qui semble certain en tout cas, c'est que notre planète est de plus en plus soumise à de méga-tempêtes de poussière, dont la dernière est tombée sur Sydney et une partie de l'Australie mercredi dernier (voir notre post Red storm). Des tempêtes qui auraient, outre les désagréments qu'elles entraînent lors de leur passage, le terrible défaut de transporter d'un continent à l'autre des maladies, dont certaines mortelles comme la méningite.

Voir sur ce sujet l'excellent article "Dust storms spread deadly diseases worldwide" publié ce week-end par le toujours aussi incontournable Guardian. Les photos ci-dessus sont extraites de Dust storms around the world publié sur le site du journal.

Extrait : "Laurence Barrie is chief researcher at the World Meteorological Organisation (WMO) in Geneva, which is working with 40 countries to develop a dust storm warning system. He said: "I think the droughts [and dust storms] in Australia are a harbinger. Dust storms are a natural phenomenon, but are influenced by human activities and are now just as serious as traffic and industrial air pollution. The minute particles act like urban smog or acid rain. They can penetrate deep into the human body."

Saharan storms are thought to be responsible for spreading lethal meningitis spores throughout semi-arid central Africa, where up to 250,000 people, particularly children, contract the disease each year and 25,000 die. "There is evidence that the dust can mobilise meningitis in the bloodstream," said Barrie.

Higher temperatures and more intense storms are also linked to "valley fever", a disease contracted from a fungus in the soil of the central valley of California. The American Academy of Microbiology estimates that about 200,000 Americans go down with valley fever each year, 200 of whom die. The number of cases in Arizona and California almost quadrupled in the decade to 2006.

Scientists who had thought diseases were mostly transmitted by people or animals now see dust clouds as possible transmitters of influenza, Sars and foot-and-mouth, and increasingly responsible for respiratory diseases. A rise in the number of cases of asthma in children on Caribbean islands has been linked to an increase in the dust blown across the Atlantic from Africa. The asthma rate in Barbados is 17 times greater than it was in 1973, when a major African drought began, according to one major study. Researchers have also documented more hospital admissions when the dust storms are at their worst.

"We are just beginning to accumulate the evidence of airborne dust implications on health," said William Sprigg, a climate expert at Arizona University.

Ou quand catastrophes naturelles et nouvelles menaces sanitaires se rejoignent.

Sur Sydney après la tempête, voir "Sydney wises up to saving water".