Climate Change Implications and Use of Early Warning Systems for Global Dust Storms - Reducing Disaster: Early Warning Systems for Climate Change - page 149

suspended soil particles (Urban et al. 2009 ; Steenburgh et al. 2012 ; Wilcox 2012 ).
A disturbance to the crust or a reduction in vegetation cover increases the risk of a dust
storm occurrence, as the loosened sediments are free to be picked up by high winds.
Dust storms can result in the deposition of foreign sediments on crops, blocking
sunlight and causing them to suffocate. Dust particles and the pollutants they carry
can contribute to compromised air quality and human health and can also infl uence
climatic patterns and the energy balance of the earth system (Shao et al. 2011 ).
In general, early warning systems could help to contribute to three main elements
necessary to prepare for a dust event: (1) communication of the actual event occur-
ring, (2) its projected intensity and (3) its projected physical and geographic impact.
With the fi rst element, the general awareness of the event is heightened. The second
and third elements of projected impacts can help people determine how to prepare
for the dust event by taking measures such as evacuating, seeking cover, sealing
doors and windows and securing outdoor assets such as vehicles, farming and man-
ufacturing equipment. Additional preparation for farmers could include harvesting
all or part of a crop early, if there is enough time before the dust storm hits (Stefanski
and Sivakumar 2009 ).

8.2 Physical Characteristics of Dust Storms

8.2.1 Dust Storm Frequency and Origination

Dust storms can occur naturally or be induced by anthropogenic activity. A dust
storm occurs naturally when high winds blow over soils that are vulnerable to sur-
face disturbance (Wilcox 2012 ). Areas where soils have dried out due to prolonged
drought or sudden dryness, or where there are a signifi cant amount of dried out
lakebed sediments, are also prone to dust storms. A dust storm that originated due
to dried out sediments around Laguna Mar Chiquita in Argentina is pictured in
Fig. 8.2 . Anthropogenic activities that can cause or increase the chances or intensity
of a dust storm include clearing of land for agricultural or infrastructure develop-
ment, overgrazing and poor agricultural practice (Stefanski and Sivakumar 2009 ).
In dust storm-prone regions, storms can collectively occur on more than 300
days a year such as in Japan (MoE 2008 ) or fewer than 30 days a year 1 such as in
the United States (NCDC/NOAA 2013 ). Approximately 2,000 teragrams (Tg) of
dust is emitted into the atmosphere per year with land surfaces receiving 75 % of the
dust that is redeposited and 25 % deposited in the ocean (Shao et al. 2011 ). The
Sahara Desert region alone emits 500-1,000 Tg/year, making it the most signifi cant

1 Based on average number of dust days in the United States for the past 10 years reported in the
U.S. National Climatic Data Center database.