UNCCD: The problem of sand and dust storms is exacerbated by poor land and water management, drought and climate change. Choosing the correct agricultural practices can stem them
by Emanuele Isonio
In different areas of the world they are known by many names: sirocco, haboob, yellow dust, white storms or Harmattan. All terms that indicate sand and dust storms (known on a technical level with the acronym of SDS, Sand and Dust Storms). A natural and seasonal phenomenon that is certainly not new. But, decade after decade, they are increasing. Aggravated by poor land and water management, drought and climate change.
This was recalled by the UNCCD, the UN Convention on the fight against desertification, in a meeting that took place in recent days in Samarkand, Uzbekistan, during the meeting called to take stock of global progress in the implementation of the convention.
An underestimated phenomenon
The UNCCD estimates that around 2 billion tonnes of sand and dust enter the atmosphere every year, an amount equal in weight to 350 Great Pyramids of Giza.
“The sight of dark clouds of sand and dust swallowing everything in their path and turning day into night is one of nature’s most intimidating sights. It is a costly phenomenon that wreaks havoc everywhere, from North and Central Asia to sub-Saharan Africa”, underlines Ibrahim Thiaw, Executive Secretary of the UNCCD. “Sand and dust storms also pose a formidable challenge to achieving sustainable development. Human activities exacerbate them but can also reduce them”.
Of course, fluctuations in intensity, magnitude, or duration “can make SDS unpredictable and dangerous.” Also because their impact is absolutely not limited to the countries in which they are born and developed.
Not only arid areas are affected
“Dust and sand storms have become increasingly frequent and severe with substantial transboundary impacts. They influence various aspects of the environment, climate, health, agriculture, livelihoods and socioeconomic well-being of individuals, with impacts that can be significant,” says Feras Ziadat, FAO technical officer and president of the United Nations Coalition for the fight against SDS. “In the areas of origin, they damage crops, affect livestock and devastate the soil. In depositional areas, atmospheric dust, especially in combination with local industrial pollution, can cause or worsen human health problems such as respiratory diseases. Communications, energy production, transportation and supply chains can also be disrupted by poor visibility and mechanical failures caused by dust.”
Obviously, sand and dust storms are common in arid areas with dust often transported over great distances. They are in fact capable of traveling thousands of kilometers, well beyond international borders. But, in addition to low latitudes and subhumid areas where there is little or no plant cover, SDS can also occur in other environments, including agricultural areas and high-latitude humid regions, when specific atmospheric and wind conditions coincide. Such storms are important for the functioning of ecosystems, but they also create numerous risks for society, in agriculture and other socioeconomic sectors. Yields and productivity of crops, trees, pastures and livestock are negatively affected. And it won’t get any better in the future. With climate change, droughts and changes in land use are expected to increase the frequency and risk of SDS.
Millionaire economic costs
With them, the economic damage will obviously also increase. For example, they cost the oil sector in Kuwait around $190 million a year. A single SDS event in 2009 caused an estimated $229 million to $243 million in damage in Australia. The UNCCD also recalls that the drying of the Aral Sea, located on the border between Uzbekistan and Kazakhstan, emits more than 100 million tons of dust and poisonous salts every year, generating losses equal to 44 million dollars per year. year.
A World Bank report reveals that, in MENA countries alone (Middle East and North Africa), SDS produce annual economic damage of 150 billion dollars, equal to 2.5% of regional GDP.
The agricultural sector is obviously one of those that suffers the greatest costs from SDS, due to the destruction or reduction of crops, the death of animals or the reduction of milk or meat yields 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. This can lead to partial or total crop loss in a region, with long-term effects on some perennial crops due to tree or crop damage.
Interventi multisettoriali e sistemi di allerta precoce
Una nota positiva è che la polvere trasportata dalle tempeste può contenere nutrienti del suolo come azoto, fosforo e potassio, nonché carbonio organico. Alcuni luoghi traggono vantaggio da questa deposizione di nutrienti sulla terra. Una volta depositati, questi possono fornire nutrienti alle colture sottovento o alle aree di pascolo. Ma tali benefici limitati, tuttavia, sono di gran lunga controbilanciati dai danni arrecati.
Per far fronte al problema, secondo l’Unccd sono necessarie diverse misure: serve in primo luogo un approccio multisettoriale, basato sulla condivisione delle informazioni. Occorre poi intervenire ripristinando i territori colpiti dalle tempeste di sabbia, utilizzando pratiche di gestione del suolo e dell’acqua per proteggere i suoli e aumentare la copertura vegetale, che hanno dimostrato di ridurre significativamente l’estensione e la vulnerabilità delle aree di origine e di ridurre l’intensità dei tipici eventi SDS.
Un aspetto particolarmente cruciale riguarda ovviamente le pratiche agricole: così come una cattiva agricoltura può aumentare la frequenza delle tempeste di sabbia, al contrario le scelte agricole virtuose possono infatti ostacolarle. Altrettanto importante è costruire un sistema di allerta precoce e di monitoraggio, basandosi su conoscenze aggiornate sui rischi e previsioni, con la partecipazione di tutte le parti interessate (comprese le popolazioni a rischio) per garantire che gli allarmi siano forniti in modo tempestivo e mirato.