Sand and dust storms (SDS) are an underappreciated problem now “dramatically” more frequent in various places around the world, according to the UN Convention to Combat Desertification (UNCCD). The five countries of Central Asia, as well as Mongolia, Iran, Iraq and even Turkey—where SDS are not yet common—are among nations worried the phenomenon could spread, intensify and get out of hand.
An estimated 2bn tonnes of sand and dust, an amount equal in weight to 350 Great Pyramids of Giza, now enters the atmosphere every year, says the UNCCD, pointing out that the SDS impacts occur far beyond the sand and dust source regions.
In some areas, it adds, desert dust doubled in the last century.
The dried-up Aral Sea, which lies between Kazakhstan and Uzbekistan, is a major source of SDS, emitting more than 100mn tonnes of dust and poisonous salts every year, impacting the health not just of people living in the vicinity, but far beyond and generating annual losses of $44mn.
That was just one shocking example highlighted by the UNCCD as last week it held a five-day meeting in Samarkand, Uzbekistan to take stock of global progress in battling SDS, around a quarter of which can be attributed to human activities.
The meeting included a session hosted by the Government of Uzbekistan on ways to address the impacts of SDS on global agriculture, industry, transportation, water and air quality and human health.
Ibrahim Thiaw, UNCCD’s executive secretary, said: “The sight of rolling dark clouds of sand and dust engulfing everything in their path and turning day into night is one of nature’s most intimidating spectacles. It is a costly phenomenon that wreaks havoc everywhere from Northern and Central Asia to sub-Saharan Africa.”
“Sand and dust storms present a formidable challenge to achieving sustainable development. However, just as sand and dust storms are exacerbated by human activities, they can also be reduced through human actions,” he added.
While SDS are a regionally common and seasonal natural phenomenon, the problem is exacerbated by poor land and water management, droughts, and climate change, according to UNCCD experts.
And fluctuations in their intensity, magnitude or duration can make SDS unpredictable and dangerous.
“Sand and dust storms have become increasingly frequent and severe having substantial transboundary impacts, affecting various aspects of the environment, climate, health, agriculture, livelihoods and the socioeconomic well-being of individuals. The accumulation of impacts from sand and dust storms can be significant,” said Feras Ziadat, technical officer at the Food and Agriculture Organization of the UN (FAO), chair of the UN Coalition on Combating Sand and Dust Storms.
Added Ziadat: “In source areas, they damage crops, affect livestock, and strip topsoil. In depositional areas atmospheric dust, especially in combination with local industrial pollution, can cause or worsen human health problems such as respiratory diseases.
“Communications, power generation, transport, and supply chains can also be disrupted by low visibility and dust-induced mechanical failures. The United Nations Coalition on Combating Sand and Dust Storms, currently chaired by FAO, was created in 2019 to lead global efforts to tackle SDS.”
SDS are known by many local names: the sirocco, haboob, yellow dust, white storms, or the harmattan, for instance.
SDS events typically originate in low-latitude drylands and sub-humid areas where vegetation cover is sparse or absent. They can also occur in other environments, including agricultural and high-latitude areas in humid regions, when specific wind and atmospheric conditions coincide.
The storms often have significant economic impacts: for example, they cost the oil sector in Kuwait an estimated $190mn annually, while a single SDS event in 2009 resulted in damage estimated at $229-243mn in Australia.
The major global sources of mineral dust are in the northern hemisphere across North Africa, the Middle East and East Asia. In the southern hemisphere, Australia, South America and Southern Africa are the main dust sources.
More than 80% of Central Asia is covered by deserts and steppes which, coupled with climate change and lasting droughts, represent a major natural source of sand and dust storms.
As well as their effects on human health, SDS can impose major costs on the agricultural sector through crop destruction or reduced yield, animal death or lower yields of milk or meat, and damage to infrastructure.
For annual crops, losses are due to burial of seedlings or crops under sand deposits, loss of plant tissue and reduced photosynthetic activity as a result of sandblasting. This can lead to complete crop loss in a region or reduced yield.
On a positive note, SDS dust can contain soil nutrients such as nitrogen, phosphorus and potassium, as well as organic carbon. Some places benefit from this nutrient deposition on land, and mineral and nutrient deposition on water, particularly ocean bodies. When deposited, these can provide nutrients to downwind crop or pasture areas. These limited benefits, however, are far outweighed by the harms done.
Globally, the main large dust sources are dried lakes; local sources include glacial outwash plains, volcanic ash zones and recently ploughed fields, says UNCCD.
Impact mitigation, through preparedness to reduce vulnerability, increases resilience and enables a timely, effective response to SDS events, it adds.