Sand and dust storms negatively affect the health and livelihoods of millions of people across the world. In the Middle East and North Africa, about $13 billion in GDP is lost every year due to dust storms.
In recent decades they have increased in frequency and intensity due to increased human activity and prolonged drought, especially in Iran.
The source of sand and dust storms are the deserts and drylands which cover around 40 per cent of the Earth’s land area. Some 2-3 billion tons of fine soil particles leave Africa every year in dust storms, which contribute to depleting soil fertility locally, but their effects can be felt in many other parts of the globe: Saharan dust increases asthma attacks in children in the Caribbean.
Most dust storms are natural events, but they can be exacerbated by climate change, drought, land degradation and unsustainable management of land and water resources. Whereas sand particles are bigger and do not travel far, dust particles can travel thousands of miles.
A side event at the United Nations Environment Assembly (UNEA) on 26 May, organized by Iran and Mongolia, brought together experts on sand and dust storms to discuss their impacts and how to forecast and mitigate them. One conclusion was that the issue needs to be prioritized at the global level.
While the UNEA event focused mainly on the negative effects of these storms, it also mentioned that long-distance Saharan dust transport in the atmosphere has beneficial effects in terms of fertilizing soils far away in the Amazon jungle. Dust takes a very active part in terrestrial and oceanic biogeochemical cycling and affects climate globally. The various interactions are complex and not fully understood. Dust fertilizes and sustains both oceans and forests. Dust affects the climate system and can cause drought intensification due to changes in the Earth’s radiative balance. On the other hand, dust can enhance precipitation by acting as nuclei for raindrops.
One of the participants at the event, Nicholas Middleton from Oxford University in the UK, said UNEP could help by conducting more assessments of the economic impact of sand and dust storms, and by gathering more knowledge on the sources, trajectories and depositions of the storms.
Others said UNEP’s expertise could be tapped into by countries seeking to establish adaptation and mitigation projects.
Well-known mitigation measures in semi-arid areas include stabilizing soil surfaces through mulching, shrub and tree plantation, wind breaks, and the erection of barriers, for example, using dead vegetation. Since there are few options to halt these storms in the short or medium term, local adaptation and mitigation strategies will need to be elaborated.
Economic and health effects
Labour productivity and household incomes drop sharply during these storms: millions of people can’t reach work; factories and offices close.
They can affect regional economies by forcing airports and schools to close, interrupting communications and supply chains, destroying crops and increasing hospital admissions. They can reduce agricultural productivity by blowing away topsoil. Dust on crops has been shown to reduce photosynthesis and negatively affect yields.
Fine particles of dust can travel thousands of miles on the back of these storms, which may also carry pathogens and harmful substances, causing acute and chronic respiratory problems.
Dust storms cause poor air quality. The World Health Organization estimates that seven million people die from poor air quality every year; risks include strokes, heart disease, lung cancer, and respiratory diseases like asthma.
Each spring Japan is plagued with “yellow sands” as a result of dust storms that originate in northeast Asia. These storms decrease visibility, increase soil-derived and anthropogenic metals, and are believed to be responsible for worsened symptoms in asthmatics, heightened cases of respiratory issues, instances of skin irritation, and widespread distribution of fungi.
Saharan storms are thought to be responsible for spreading lethal meningitis spores throughout central Africa, where up to 250,000 people contract the life-threatening disease every year.
Hot spots
Primary dust storm regions are the Sahara Desert, the Middle East, the Taklamakan Desert in northwest China, southwest Asia, central Australia, the Etosha and Makgadikgadi basins of southern Africa, the Salar de Uyuni in Bolivia and the Great Basin in the USA.
In Iraq, the government recorded 122 dust storms and 283 dusty days in a single year; sources suggest that, within the next 10 years, Iraq could witness 300 dust events per year.
In China, as much as 330,000 tons of sand fell on Beijing in a single night in 2006.
What can be done?
Early warning, improved monitoring and better preparedness, and international cooperation can help mitigate the impact of sand and dust storms.
In 2006 the World Meteorological Organization set up a Sand and Dust Storm Warning and Assessment System; new forecasting models are being developed. In 2014 the first regional dust forecasting centre was set up in Barcelona.
Early warning systems at the national and regional level could prepare people for dust storms, giving them time to take cover, seal doors and vacate the streets, thus preventing car accidents; and could give farmers time to bring in livestock, farm equipment and, if warned far enough in advance, allow them to harvest all or a portion of a crop before a storm.
Regional and international cooperation among countries will lead to greater understanding of the transportation paths of dust storms, particle content, and their impacts on the environment. Protecting lakes from desiccation, and restoring dryland ecosystems, will lead to a reduced occurrence of dust storms and ensure healthier ecosystems.
Better monitoring systems can help policymakers determine whether or not disease outbreaks are the result of transported sand and dust, or the result of human transport. They can also help better understand the impact of human activities on sand and dust storms and how they impact the environment and climate systems.
Tree planting can help: China’s Great Green Wall project has reduced the frequency and intensity of dust storms, research suggests. By 2050 China will have planted more than 100 billion trees since 1978. Senegal has planted 12 million trees covering 40,000 hectares as part of a pan-African scheme to combat desertification in the Sahel.
