Dictionary Definition
drought
Noun
1 a temporary shortage of rainfall
2 a prolonged shortage
User Contributed Dictionary
English
Etymology
''drūġaþPronunciation
- a UK /ˈdɹaʊt/ /"draUt/
Translations
a period of below average rain fall
References
Extensive Definition
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 precipitation.
It can have a substantial impact on the ecosystem and agriculture of the affected
region. Although droughts can persist for several years, even a
short, intense drought can cause significant damage and harm the
local economy According
to the UN, an
area of fertile soil the size of Ukraine is lost every year because
of drought, deforestation and climate instability.
Implications
Drought is a normal, recurring feature of the
climate in most parts of the world. 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 catastrophes, 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.
According to a UN climate report, the Himalayan
glaciers that are the sources of Asia's biggest rivers
- Ganges,
Indus,
Brahmaputra,
Yangtze,
Mekong,
Salween and
Yellow -
could disappear by 2035 as temperatures rise. Approximately 2.4
billion people live in the drainage
basin of the Himalayan rivers. India, China, Pakistan, Bangladesh,
Nepal and
Myanmar
could experience floods followed by droughts in coming decades.
Drought in
India affecting the Ganges is of particular concern, as it
provides drinking
water and agricultural irrigation for more than 500
million people.
The west coast of North
America, which gets much of its water from glaciers in mountain
ranges such as the Rocky
Mountains and Sierra
Nevada, also would be affected.
In 2005, parts of the Amazon basin
experienced the worst drought in 100 years. A 23 July 2006 article
reported
Woods Hole Research Center results showing that the forest in
its present form could survive only three years of drought.
Scientists at the Brazilian
National Institute of Amazonian Research argue in the article
that this drought response, coupled with the effects of deforestation on regional
climate, are pushing the rainforest towards a "tipping
point" where it would irreversibly start to die. It concludes
that the rainforest
is on the brink of being turned into savanna or desert, with catastrophic
consequences for the world's climate. According to the
WWF, the combination of climate
change and deforestation increases the drying effect of dead
trees that fuels forest fires. Paradoxically, some proposed
short-term
solutions
to global warming also carry with them increased chances of
drought.
Causes
- Malnutrition, dehydration and related diseases.
- Famine due to lack of water for irrigation.
- Social unrest.
- Mass migration, resulting in internal displacement and international refugees.
- War over natural resources, including water and food.
- Reduced electricity production due to insufficient available coolant for power stations and reduced water flow through hydroelectric dams.
- Snakes have been known to emerge and snakebites become more common.
- Creates windblown dust bowls which erodes the landscape, damages terrestrial and aquatic wildlife habitat
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
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:
- 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.
- Hydrological drought is brought about when the water reserves available in sources such as aquifers, lakes and reservoirs falls below the statistical average. Like an agricultural drought, this can be triggered by more than just a loss of rainfall. For instance, Kazakhstan was recently awarded a large amount of money by the World Bank to restore water that had been diverted to other nations from the Aral Sea under Soviet rule. Similar circumstances also place their largest lake, Balkhash, at risk of completely drying out.
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 Yemen has revealed that their water table (underground water level) is put at grave risk by over-use to fertilize their Khat crop. Careful monitoring of moisture levels can also help predict increased risk for wildfires, using such metrics as the Keetch-Byram Drought Index or Palmer Drought Index.
- Land use - Carefully planned crop rotation can help to minimize erosion and allow farmers to plant less water-dependent 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.
See also
References
External links
- National Integrated Drought Information System
- Social & Economic Costs of Drought from "NOAA Socioeconomics" website initiative
- Water scarcity from FAO Water (Food and Agriculture Organization of the United Nations)
drought in Bosnian: Suša
drought in Catalan: Sequera
drought in Czech: Sucho
drought in Danish: Tørke
drought in German: Dürre
drought in Spanish: Sequía
drought in Esperanto: Trosekeco
drought in Persian: خشکسالی
drought in French: Sécheresse
drought in Galician: Seca
drought in Croatian: Suša
drought in Italian: Siccità
drought in Hebrew: בצורת
drought in Lithuanian: Sausra
drought in Hungarian: Aszály
drought in Dutch: Droogte
drought in Japanese: 旱魃
drought in Norwegian: Tørke
drought in Norwegian Nynorsk: Tørke
drought in Polish: Susza
drought in Portuguese: Seca
drought in Romanian: Secetă
drought in Quechua: Ch'akiy
drought in Russian: Засуха
drought in Simple English: Drought
drought in Serbian: Суша
drought in Finnish: Kuivuuskausi
drought in Swedish: Torka
drought in Turkish: Kuraklık
drought in Contenese: 乾旱
drought in Chinese: 干旱
Synonyms, Antonyms and Related Words
absence, appetite, aridity, aridness, beggary, canine appetite,
corkiness, defectiveness, deficiency, deficit, deprivation, destitution, dryness, emptiness, empty stomach,
famine, hollow hunger,
hunger, hungriness, imperfection, impoverishment, incompleteness, juicelessness, lack, need, omission, polydipsia, relish, saplessness, shortage, shortcoming, shortfall, starvation, stomach, sweet tooth, tapeworm, taste, thirst, thirstiness, torment of
Tantalus, want, wantage, waterlessness, watertight
integrity, watertightness