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A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average Australian Drought and Climate Change , retrieved on June 7th 2007..


IMPLICATIONS

For most regions, drought is a normal, recurrent feature of the climate, and having adequate drought mitigation strategies in place can greatly reduce the impact. Recurring or long-term drought can bring about Desertification . Recurring droughts in the Horn Of Africa have created grave Ecological Catastrophe s, prompting massive Food Shortages , Still Recurring . To the north-west of the Horn, the Darfur Conflict in neighboring Sudan , also affecting Chad , was fueled by decades of drought; combination of drought, Desertification and Overpopulation are among the causes of the Darfur Conflict , because the Arab Baggara Nomads searching for water have to take their livestock further south, to land mainly occupied by non-Arab farming peoples. Looking to water to find peace in Darfur

According to a UN climate report, the 2007 New Scientist , Catherine Brahic

In 2005, parts of the , March 22 , 2006 . Retrieved September 28 , 2006 .


CAUSES

Generally, rainfall is related to the amount of water vapour in the atmosphere, combined with the upward forcing of the air mass containing that water vapour. If either of these are reduced, the result is drought.

Factors include:
  • Above average prevalence of high Pressure System s

  • Wind s carrying continental, rather than oceanic air masses (ie. reduced water content)

  • El Nino (and other oceanic temperature cycles)

  • Deforestation

  • some speculate that shttp://usinfo.state.gov/af/Archive/2005/Oct/26-779234.html Nigerian Scholar Links Drought, Climate Change to Conflict in Africa Oct, 2005.



CONSEQUENCES

Periods of drought can have significant environmental, economic and social consequences. The most common consequences include:
  • Death of Livestock .

  • Reduced Crop Yield s.

  • Wildfires , such as Australia n Bushfire s, are more common during times of drought. http://txforestservice.tamu.edu/shared/article.asp?DocumentID=406&mc=fire Texas Forest Service description of the Keetch-Byram Drought Index (KBDI) from 12/27/2002

  • Shortages of water for Industrial users. http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2005/03/06/MNGE2BL7161.DTL Parched village sues to shut tap at Coke March 6, 2005http://www.greenpeace.org/international/news/sweden-nuclear-closure-040806 Greenpeace reports on a Swedish drought and its potential impact on their nuclear power industry. 04 August 2006

  • Desertification

  • Dust Storms , when drought hits an area suffering from desertification and Erosion

  • Malnutrition , Dehydration and related diseases.

  • Famine due to lack of water for Irrigation .

  • Social Unrest .

  • Mass Migration , resulting in Internal Displacement and international Refugee s.

  • War over natural resources, including water and food.

  • Reduced electricity production due to insufficient available coolant


The effect varies according to vulnerability. For example, subsistence farmers are more likely to migrate during drought because they do not have alternative food sources. Areas with populations that depend on Subsistence Farming as a major food source are more vulnerable to drought-triggered famine. Drought is rarely if ever the sole cause of famine; socio-political factors such as extreme widespread poverty play a major role. Drought can also reduce water quality, because lower water flows reduce dilution of pollutants and increase Contamination of remaining water sources.


STAGES OF DROUGHT

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As a drought persists, the conditions surrounding it gradually worsen and its impact on the local population gradually increases. Droughts go through three stages before their ultimate cessation http://www.nws.noaa.gov/om/brochures/climate/Drought.pdf NOAA factsheet, retrieved April 100th 2007:
# Meteorological drought is brought about when there is a prolonged period with less than average precipitation. Meteorological drought usually precedes the other kinds of drought.
# Agricultural droughts are droughts that affect crop production or the ecology of the Range . This condition can also arise independently from any change in precipitation levels when Soil conditions and erosion triggered by poorly planned agricultural endeavors cause a shortfall in water available to the crops. However, in a traditional drought, it is caused by an extended period of below average precipitation.
#, at risk of completely drying out http://news.bbc.co.uk/2/hi/asia-pacific/3397077.stm BBC article from 2004 concerning the risk of Kazakhstan losing the lake.


DROUGHT MITIGATION STRATEGIES

  • Desalination of sea water for irrigation or consumption.

  • Drought monitoring - Continuous observation of rainfall levels and comparisons with current usage levels can help prevent man-made drought. For instance, analysis of water usage in .

  • Land use - Carefully planned Crop Rotation can help to minimize erosion and allow farmers to plant less water-dependant crops in drier years.

  • Rainwater Harvesting - Collection and storage of rainwater from roofs or other suitable catchments.

  • Recycled Water - Former wastewater (sewage) that has been treated and purified for reuse.

  • Transvasement - Building canals or redirecting rivers as massive attempts at Irrigation in drought-prone areas.

  • Water Restrictions - Water use may be regulated (particularly outdoors). This may involve regulating the use of sprinklers, hoses or buckets on outdoor plants, the washing of motor vehicles or other outdoor hard surfaces (including roofs and paths), topping up of swimming pools, and also the fitting of water conservation devices inside the home (including shower heads, taps and dual flush toilets).

  • Cloud Seeding - an artificial technique to induce rainfall. http://www.chinadaily.com.cn/english/doc/2004-07/24/content_351196.htm



SEE ALSO




REFERENCES