2009 has seen some seriously big dust storms blowing around the world. The most recent was the huge storm in Sydney, Australia, the result of a long-lasting drought, followed by a smaller storm hitting Brisbane
, but there will be more to come from that continent. One of the most memorable dust storms this year for scientists was the one that originated in western China
. That dust cloud went around the world in only thirteen days. There have also been dust storms in Iraq, Pakistan, Saudi Arabia, Afghanistan, and East Africa. A geography professor at Oxford University, Andrew Goudie
told the Observer
"The numbers of major dust storms go up and down over the years. In Australia and China they tailed off from the 1970s then spiked in the 1990s and at the start of this decade. At the moment they are clearly on an upward trajectory."
Dust storms redistribute valuable nutrients
, such as iron and nitrogen, and a new theory states that dust storms might deflect sunlight, thus slowing down climate change. However, there is growing proof that dust storms are a health hazard. Dust clouds harbour viruses, fungi and bacteria as well as heavy metals and other pollutants.
Dust storms arise from deserts, including land that has been newly turned into deserts (desertification). Human practices, which are thought to be causing global warming, definitely contribute to desertification through deforestation and agricultural practices. Another human activity is Toyota-ization
, a term coined by Professor Goudie. The word refers to the increasing use of four wheeled drive vehicles in deserts throughout the world. Goudie said
"If you take almost any desert now, people go all over it in four-wheel drives. 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."
Recent advances in technology have meant that scientists have been able to track dust, and the findings have been revealing. Dust from Asia, for example, is found over the western United States in the spring months and has been found to be a contributing component in Los Angeles' smog. It has also been linked to poor air quality in western Asia and Russia. Saharan dust has been tracked to Spain, Italy and Greece, and all the way to South Wales.
Scientists are studying the relationshiop between Saharan dust storms and the incidence of meningitis meningitis
in the dry areas of central Africa. Meningitis in this area makes to 250,000 people sick every year, with up to 25,000 deaths.
In California, a disease called valley fever
, caused by a fungus that grows in soil, has been linked to warmer temperatures and storms. There has been an increase
in the incidence of valley fever since 2000, attributed to a growing population and an increase in construction activities. There are now about 200,000 new cases of valley fever in the United States each year. The fungus is also found in South America.
Now scientists are finding that dust clouds can carry other diseases such as influenza, Sars, and foot-and-mouth. For example, the spread of bird flu has been linked
to dust storms in Asia. Foot-and-mouth disease
is caused by a virus that affects animals but rarely humans. An outbreak in Great Britain in 2001 saw a wide scale slaughter of farm animals in an effort to control the disease, among other efforts. Control of the outbreak was enormously expensive. The outbreak has been linked
to a dust storm that occurred earlier that year.
A striking example of the deadly air quality that can result from a dust storm is the annual yellow dust storm
that smothers South Korea. The dust comes from the Gobi desert and is full of heavy metals, such as lead, cadmium and copper. On April 8, 2006 during a dust storm in South Korea, U.S. officials measured pollution levels of over 2,200 parts per million. The U.S. considers levels of 301-500 parts per million in a cubic meter of air as “hazardous.”
When scientists began to research the potential for microbes to be distributed around the world in dust storms, they thought
that Ultra Violet radiation (UV) would kill the bacteria, viruses and fungi. This idea has since been shown to be wrong. Microbiologist Dale W. Griffin told Discovery Channel that 20 to 30% of the microbes carried in dust storms are "pathogens to some type of plant or animal."
The idea of studying microbes carried with dust storms is relatively new. A United States Geologic Survey
(USGS) geologist Eugene Shinn
was the first to theorize that pathogens were being spread through dust storms in the late 1990s. Shinn theorized that pathogens carried by dust storms were responsible for the shrinking of coral reefs
in the Carribean.
The World Meteorological Organisation
(WMO), based in Geneva, is working to develop a dust storm warning system., the Sand and Dust Storm Warning Advisory and Assessment System
(SDS-WAS). The goal
of the system is to
"... enhance the ability of countries to deliver timely and quality sand and dust storm forecasts, observations, information and knowledge to users through an international partnership of research and operational communities. Today, there are twelve SDS-WAS operational or research sand and dust forecasting centers around the world."
WMO's Chief Researcher, Laurence Barrie, told the Observer
"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."
has been a serious issue in many countries, such as Italy, many African nations, and Australia, but now we are learning that this is a problem that everyone in the world shares. China is attempting to slow the advance of its deserts, and reports
say that China is "winning." China Daily said that the battle is costing 120 billion yuan a year, and estimates that 15% of local species are facing extinction.