Dust storms are caused by extreme drought, overgrazing of pastures, cutting down of trees and shrubs, and improper agricultural practices. Blowing winds are the main factor in moving soil particles (1). Dust storms are a serious problem in most parts of Iran, an arid country that employs some outdated agricultural practices. As David Michel put it, Iran is, quite literally, being blown away. Stifling dust storms frequently now envelope both big cities and rural towns across much of Iran. They threaten to disrupt crucial parts of public and economic life, education, commerce, public health, agriculture, trade and transportation. Swirling clouds of windblown silt, soil, and sediment affected 23 of Iran’s 31 provinces in 2013(2).
The storms, which have increased in frequency, are today considered a calamitous but unsurprising part of life in Iran. These storms are complex events influenced by atmospheric conditions which mainly arise due to high-speed winds, bare land, and arid climate. These storms can have major effects on weather conditions. They also cause great damages to people’s lives and possessions. Dust storms occur more frequently around certain latitudes, particularly 40o north and south of the equator. The western winds in these zones carry dust particles and transfer them to t other parts of the earth. When these dust particles enter the earth’s atmosphere, they cause physical, chemical and biological alterations to it. This altered air is called polluted air. An atmospheric substance is considered a pollutant when it causes considerable alteration, positive or negative, to human beings, animals and plants. Therefore, each natural or artificial substance which enters the air and alters its nature is considered an air pollutant. Some studies have been done about the pollutant role of this phenomenon, however, there is no scientific consensus around what determines the origin of this phenomenon(3).
Understanding dust storms
Dust storms normally occur in arid and semi-arid regions of the world. Iran is located in the center of the dust belt stretching from the northwest coast of Africa, through North Africa and the Middle East, and across South-Central Asia to China (4). Significant portions of this region were once fertile lands supporting a self-sufficient population, but due to the destructionof soil and other sustainable natural resources, they gradually shifted to reach today’s barren state. In many countries, wind erosion has depleted the soil, and in many, it has transformed once-fertile lands into sandy deserts (5).
Heavy winds rushing over Iran’s dry, flat plateaus, deserts and salt beds pick up loose soil particles, sand, bits of dirt and grit into the air and carry them far from the lifting location, sometimes thousands of kilometers away. The process by which this massive transportation takes place is called wind erosion (6, 7, 8).
Wind erosion annually transports thousands of tons of surface soil, grit, sand and sediments from every square kilometers of the country as dust storms pass. The end results of a dust storm could be extremely devastating: the closing of roads, rail lines, airports, schools and offices, the slowdown of economic activity, the destruction of farmland, clogged machinery, and the cloaking of towns and cities in debilitating air pollution are just some of the risks dust storms pose. (9).
There are many causes for dust storms. Two main contributing factors are low vegetation cover and disturbance of soil surfaces. The presence of plants reduces soil erosion and dust storms, because it keeps the soil intact, reduces wind momentum, and traps moving soil particles. In spaces between the plants, many undisturbed desert soils are naturally armored by hardened physical and biological crusts. Low vegetation cover can especially be a problem in drought years in abandoned agricultural fields, which are generally dominated by annual plants. This means that the consequences of dust storms, including motor vehicle accidents, are high in a drought year and low in years with more precipitation (10).
Similarly, in places where land-use activities destroy or reduce soil crusts and weaken soil stability, experts know to assume higher dust storm activity than in places where soils are left undisturbed. Future climate scenarios predict that drought conditions will worsen, and therefore more dust storms are likely (10).
A sound understanding of the processes that cause wind erosion is key in developing effective control strategies. Although conservation practices can be successful in controlling erosion, droughts can cause a shortage of residue, and erosive winds will not always blow in a prevailing direction. Thus, land managers must be ever vigilant and combinations of practices may be needed when planning a wind erosion control system.
The role of government
Iran’s dust storm problem and its attendant issues are not uniquely attributable to the course of nature, but also to government mismanagement. The Iranian government’s renewable natural resources and land management practices are believed to have severely worsened environmental conditions that directly exacerbate dust storms in recent years. Iran’s neighbors have also made policy choices that contribute to this issue, with heavy repercussions in the region. Compounding these national and international pressures, global climate change may further increase drought and desertification across Iran and southwest Asia, potentially intensifying future dust and sand storms.
Water supply is a major and increasing sources of concern in arid countries like Iran. Iran’s cities lose considerable amount of their water supply through leaky pipes. Iran’s irrigation system is also considered highly inefficient and outdated. More than half of Iran’s renewable water used in agriculture is lost. Underground fresh water table has significantly depleted since the revolution in 1979. Surmounting Iran’s environmental challenges will require serious reorientation of policies and resources. The cost of new technologies, conservation practices and other measures to meet only projected water needs in 2050 could top $3 billion a year, experts say.
The consequent damage from water stress, desertification, and pollution, when taken together, could impose debilitating long-term burdens on the region. The annual cost of Iran’s environmental sector already amounts to a whopping 5 to 10 percent of GDP, according to the World Bank. In contrast, tough U.S. and international sanctions shrank Iran’s GDP by some 1.4 percent in 2012, according to the U.S. Government Accountability Office. Over time, if decisive action to prevent and counter dust storms is not taken, valuable resources will be further depleted, productivity diminished, and public health damaged (11).
While pressures such as climate change, natural processes, and the decision of its neighbors are out of Iran’s control, it is within the Iranian government’s power to take decisive action about this increasingly unsustainable issue. However, the current regime seems unwilling to take such action. International environmental groups have used cash incentives and investment to encourage Iran to reform its environmental practices, but this money has mostly been funneled into the security services and other regime-sponsored areas of the economy. Without major reform, Iran seems unlikely to address the problem of dust storms and environmental degradation in the future.
Journal of Novel Applied Sciences ©2014 JNAS Journal-2014-3-10/1131-1136 ISSN 2322-5149 ©2014 JNAS