drought
See other News Centers » drought
A drought is defined as an extended period of abnormally dry weather that causes water shortages and crop damage. A drought starts when total rainfall is well below average for several months. Other signs of drought include: unusually low river flows, low groundwater and reservoir levels, very dry soil, reduced crop yields or even crop failure, and algae blooms in reservoirs and lakes. Groundwater is not replenished because not enough rain is falling to wet the soil's entire surface area and to be absorbed properly.
Drought conditions lead to increased growth of algae in lakes, ponds and other slow-moving bodies of water. The water is no longer a safe place for fish and other aquatic life. Animals that drink from the rivers or streams can become sick and die; swimmers in affected waters may become ill. The ecology of an area may be affected by the drying of wetlands, with wading birds dying out. Crop production will be lower than usual; trees may die. Wildfires spring up; lack of irrigation can lead to famine and disease.
Sociological consequences of drought range from social unrest to relocation of populations to war.
Some ways to save water:
In the house:
- Recycle! Never pour water down the drain if it can be used to water plants, wash a floor, etc.
- Replace washers in leaky faucets. One drop a second wastes 2,700 gallons (10,220 liters) of water a year!
- Repair leaky pipes. When no one is running the water in your home, take a reading of the water meter. Wait 30 minutes and then take a second reading. If the meter reading changes, you have a leak.
- Check for toilet leaks by adding food coloring to the tank. If your toilet has a leak, the color will appear in the bowl within 30 minutes. (Flush immediately to avoid stains.)
- Consider replacing an old toilet with a low-volume model that uses less than half the water of the older types.
- Replace your showerhead with a low-flow model.
- Take short showers.
- Turn off the water while washing your face, brushing your teeth or shaving.
- Wait till your dishwasher is fully loaded before running.
- Rather than letting the tap run to cool drinking water, fill a jug or pitcher and store drinking water in the refrigerator.
- Operate washing machines only when fully loaded or set the water level for the size of your load.
- Consider installing an instant hot water heater on your sink so you don't have to wait for water to become hot.
- When purchasing a new appliance, choose one that is more energy and water efficient.
Out of doors:
- If you have a well at home, check your pump periodically. If the pump turns on and off while water is not being used, you have a leak.
- When watering lawns, water in short sessions so the lawn absorbs the moisture better. Three short sessions of 10 minutes a piece, spaced 30 minutes apart, are preferable to one long 30-minute session.
- Water lawns early in the morning or after the sun has set.
- Make sure your water sprinklers are positioned so the water lands on the shrubs and lawn, and not on paved areas.
- Use sprinklers with a heavy spray. When sprinklers spray in too fine a mist, much of the water evaporates before hitting the lawn.
- Plant grass, ground cover and shrubbery that does not take as much water to survive. Group plants according to their water needs.
- Adhere to water conservation regulations and restrictions, especially if your community is experiencing a drought.
There have been a number of life-threatening droughts over the centuries. Cape Verde has suffered a number of droughts, and continues to suffer from erratic rainfall. Over 10,000 people starved to death due to droughts in the 1700s and 1800s, and a great many residents migrated to other areas.
In the early 1900s, drought led to the deaths of about 3 million people in India and 5 to 10 million people in the Soviet Union. In China, approximately 3 million people died from famine caused by drought in 1936.
America's "Dust Bowl" was a series of three droughts in the 1930s that forced the migration of large populations in the American Great Plains. Winds whipped up clouds of soil, called "dusters" or "black blizzards," crops were ruined and inhabitants suffered from dust-related health problems. The drought came on the heels of the Great Depression, battering an already impoverished population. John Steinbeck's The Grapes of Wrath told the story of the "Okies" who had to leave their homes and move to California.
| Recommended Sites: | Blogs: |
Written by 
Related Videos:
Top
drought
American Heritage Dictionary:
Top
drought
(drout) 
also drouth (drouth)
n.
also drouth (drouth)n.
- A long period of abnormally low rainfall, especially one that adversely affects growing or living conditions.
- A prolonged dearth or shortage.
[Middle English, from Old English drūgoth, akin to drȳge, dry.]
droughty drought'y adj.Britannica Concise Encyclopedia:
Top
drought
Lack or insufficiency of rain for an extended period that severely disturbs the hydrologic cycle in an area. Droughts involve water shortages, crop damage, streamflow reduction, and depletion of groundwater and soil moisture. They occur when evaporation and transpiration exceed precipitation for a considerable period. Drought is the most serious hazard to agriculture in nearly every part of the world. Efforts have been made to control it by seeding clouds to induce rainfall, but these experiments have had only limited success.
For more information on drought, visit Britannica.com.
Top
A general term implying a deficiency of precipitation of sufficient magnitude to interfere with some phase of the economy. Agricultural drought, occurring when crops are threatened by lack of rain, is the most common. Hydrologic drought, when reservoirs are depleted, is another common form. The Palmer index is used by agriculturalists to express the intensity of drought as a function of rainfall and hydrologic variables.
The meteorological causes of drought are usually associated with slow, prevailing, subsiding motions of air masses from continental source regions. These descending air motions, of the order of 660–1000 ft (200 or 300 m) per day, result in compressional warming of the air and therefore reduction in the relative humidity. Since the air usually starts out dry, and the relative humidity declines as the air descends, cloud formation is inhibited—or if clouds are formed, they are soon dissipated.
Antonyms by Answers.com:
Top
drought
n
Definition: dryness; shortage of supply
Antonyms: monsoon, wetness
Oxford Dictionary of Geography:
Top
drought
A long, continuous period of dry weather. Major causes of drought in Britain are the persistence of warm anticyclones, and the displacement of mid-latitude depressions by blocking anticyclones. Droughts in Africa, for example in the Sahel in the 1970s or in Zimbabwe in the early 1990s, result from the failure of the inter-tropical convergence zone to move sufficiently far from the equator. See absolute drought.
Columbia Encyclopedia:
Top
drought
drought, abnormally long period of insufficient rainfall. Drought cannot be defined in terms of inches of rainfall or number of days without rain, since it is determined by such variable factors as the distribution in time and area of precipitation during and before the dry period. Since ancient times droughts have had far-reaching effects on humankind by causing the failure of crops, decreasing natural vegetation, and depleting water supplies. Livestock and wildlife, as well as humans, die of thirst and famine; large land areas often suffer damage from dust storms or fire. Drought is thought by some to have caused migrations of early humans. In India and China drought has periodically brought widespread privation and death. In 1930 lack of rainfall devastated the Great Plains of the United States; called the Dust Bowl, its area spread to alarming dimensions (about 50 million acres). During 1962 much of the eastern part of the U.S. experienced the worst drought in more than 50 years; more recent severe droughts have afflicted countries in many parts of Africa. Clearcutting of trees for firewood, overgrazing, and overcultivation, which lead to land degredation, contribute to this drought cycle.
Bibliography
See C. S. Russell et al., Drought and Water Supply (1970); W. C. Palmer and L. M. Denny, Drought Bibliography (1971); R. V. Garcia and J. Escudero, Drought and Man (1986).
Word Tutor:
Top
drought
IN BRIEF: A long time of no rain.
During the drought the crops dried up and blew away.
LearnThatWord.com is a free vocabulary and spelling program where you only pay for results!
Random House Word Menu:
Top
categories related to 'drought'
- Disasters and Phenomena - drought: prolonged period without rain
- Soils and Soil Management - drought: prolonged period without rain that causes soil failure and crop death
See crossword solutions for the clue Wikipedia on Answers.com:
Top
Drought
For other uses, see Drought (disambiguation).
A drought is an extended period of months or years when a region notes a deficiency in its water supply whether surface or underground water. 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[1] and harm the local economy.[2]
This global phenomenon has a widespread impact on agriculture. Lengthy periods of drought have long been a key trigger for mass migration and played a key role in a number of ongoing migrations and other humanitarian crises in the Horn of Africa and the Sahel.
|
Contents
|
Consequences
Periods of drought can have significant environmental, agricultural, health, economic and social consequences. 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 as a major food source are more vulnerable to drought-triggered famine.
Drought can also reduce water quality, because lower water flows reduce dilution of pollutants and increase contamination of remaining water sources. Common consequences of drought include:
- Diminished crop growth or yield productions and carrying capacity for livestock
- Dust bowls, themselves a sign of erosion, which further erode the landscape
- Dust storms, when drought hits an area suffering from desertification and erosion
- Famine due to lack of water for irrigation
- Habitat damage, affecting both terrestrial and aquatic wildlife[3]
- Malnutrition, dehydration and related diseases
- Mass migration, resulting in internal displacement and international refugees
- Reduced electricity production due to reduced water flow through hydroelectric dams[4]
- Shortages of water for industrial users[5][6]
- Snake migration and increases in snakebites[7]
- Social unrest
- War over natural resources, including water and food
- Wildfires, such as Australian bushfires, are more common during times of drought.[8]
Globally
Drought is a normal, recurring feature of the climate in most parts of the world. It is among the earliest documented climatic events, present in the Epic of Gilgamesh and tied to the biblical story of Joseph's arrival in and the later Exodus from Ancient Egypt.[9] Hunter-gatherer migrations in 9,500 BC Chile have been linked to the phenomenon,[10] as has the exodus of early humans out of Africa and into the rest of the world around 135,000 years ago.[11]
Modern peoples can effectively mitigate much of the impact of drought through irrigation and crop rotation. Failure to develop adequate drought mitigation strategies carries a grave human cost in the modern era, exacerbated by ever-increasing population densities.
Regions
Recurring droughts leading to desertification in the Horn of Africa have created grave ecological catastrophes, prompting massive food shortages, still recurring.[14] 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.[15]
Approximately 2.4 billion people live in the drainage basin of the Himalayan rivers.[16] 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.[17][18][19] 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.[20][21]
In 2005, parts of the Amazon basin experienced the worst drought in 100 years.[22][23] 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.[24][25] 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.[26]
By far the largest part of Australia is desert or semi-arid lands commonly known as the outback. A 2005 study by Australian and American researchers investigated the desertification of the interior, and suggested that one explanation was related to human settlers who arrived about 50,000 years ago. Regular burning by these settlers could have prevented monsoons from reaching interior Australia.[27] In June 2008 it became known that an expert panel had warned of long term, maybe irreversible, severe ecological damage for the whole Murray-Darling basin if it does not receive sufficient water by October.[28] Australia could experience more severe droughts and they could become more frequent in the future, a government-commissioned report said on July 6, 2008.[29] Australian environmentalist Tim Flannery, predicted that unless it made drastic changes, Perth in Western Australia could become the world’s first ghost metropolis, an abandoned city with no more water to sustain its population.[30]
East Africa currently faces its worst drought in decades,[31][32] with crops and livestock destroyed.[33] The U.N. World Food Programme recently said that nearly four million Kenyans urgently needed food.[34]
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 a drought. This can be triggered by an above average prevalence of high pressure systems, winds carrying continental, rather than oceanic air masses (i.e. reduced water content), and ridges of high pressure areas form with behaviors which prevent or restrict the developing of thunderstorm activity or rainfall over one certain region. Oceanic and atmospheric weather cycles such as the El Niño-Southern Oscillation (ENSO) make drought a regular recurring feature of the Americas along the Midwest and Australia. Guns, Germs, and Steel author Jared Diamond sees the stark impact of the multi-year ENSO cycles on Australian weather patterns as a key reason that Australian aborigines remained a hunter-gatherer society rather than adopting agriculture.[35] Another climate oscillation known as the North Atlantic Oscillation has been tied to droughts in northeast Spain.[36]
Human activity can directly trigger exacerbating factors such as over farming, excessive irrigation,[37] deforestation, and erosion adversely impact the ability of the land to capture and hold water.[38] While these tend to be relatively isolated in their scope, activities resulting in global climate change are expected to trigger droughts with a substantial impact on agriculture[39] throughout the world, and especially in developing nations.[40][41][42] Overall, global warming will result in increased world rainfall.[43] Along with drought in some areas, flooding and erosion will increase in others. Paradoxically, some proposed solutions to global warming that focus on more active techniques, solar radiation management through the use of a space sunshade for one, may also carry with them increased chances of drought.[44]
Types of drought
As a drought persists, the conditions surrounding it gradually worsen and its impact on the local population gradually increases. People tend to define droughts in three main ways:[45]
- 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 fall below the statistical average. Hydrological drought tends to show up more slowly because it involves stored water that is used but not replenished. 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.[46] Similar circumstances also place their largest lake, Balkhash, at risk of completely drying out.[47]
Drought protection and relief
Strategies for drought protection, mitigation or relief include:
- Dams - many dams and their associated reservoirs supply additional water in times of drought.
- Cloud seeding - an artificial technique to induce rainfall.[48]
- 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.[49] Careful monitoring of moisture levels can also help predict increased risk for wildfires, using such metrics as the Keetch-Byram Drought Index[8] 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.
- Outdoor water-use restriction - Regulating the use of sprinklers, hoses or buckets on outdoor plants, filling pools, and other water-intensive home maintenance tasks.
- 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.
See also
- Climate change
- Collapse: How Societies Choose to Fail or Succeed
- FEMA
- Food security
- Permanent wilting point
- Topsoil
- United Nations Convention to Combat Desertification
- Water conflict
- Water crisis
Regional:
- Amazon Rainforest drought
- Droughts and famines in Russia and USSR
- Drought in Australia, Exceptional Circumstances relief payments
- Drought in the United Kingdom
- Drought in the United States
- Maya collapse
- Sahel drought
References
- ^ Living With Drought
- ^ Australian Drought and Climate Change, retrieved on June 7th 2007.
- ^ C.Michael Hogan. 2010. Abiotic factor. Ed. Emily Monosson. Encyclopedia of Earth. National Council for Science and the Environment, Washington DC
- ^ Drought affecting US hydroelectric production | Daily Estimate
- ^ Parched village sues to shut tap at Coke March 6, 2005
- ^ Greenpeace reports on a Swedish drought and its potential impact on their nuclear industry. 4 August 2006
- ^ Australians Face Snake Invasion.
- ^ a b Texas Forest Service description of the Keetch-Byram Drought Index (KBDI) from 27 December 2002
- ^ BBC - Weather Centre - Features - History and Religion - Weather in the Bible - Drought and Famine
- ^ Ancient Chile Migration Mystery Tied to Drought
- ^ Drought pushed ancient African immigration
- ^ Disappearing Lakes, Shrinking Seas
- ^ Shrinking African Lake Offers Lesson on Finite Resources
- ^ Sara Pantuliano and Sara Pavanello (2009) Taking drought into account Addressing chronic vulnerability among pastoralists in the Horn of Africa Overseas Development Institute
- ^ Looking to water to find peace in Darfur
- ^ Big melt threatens millions, says UN
- ^ Ganges, Indus may not survive: climatologists
- ^ Glaciers melting at alarming speed
- ^ Himalaya glaciers melt unnoticed
- ^ Glaciers Are Melting Faster Than Expected, UN Reports
- ^ Water shortage worst in decades, official says, Los Angeles Times
- ^ Environmental News Service - Amazon Drought Worst in 100 Years
- ^ Drought Threatens Amazon Basin - Extreme conditions felt for second year running
- ^ Amazon rainforest 'could become a desert' , The Independent, July 23, 2006. Retrieved September 28, 2006.
- ^ Dying Forest: One year to save the Amazon, The Independent, July 23, 2006. Retrieved September 28, 2006.
- ^ Climate change a threat to Amazon rainforest, warns WWF, World Wide Fund for Nature, March 9, 2996. Retrieved September 28, 2006.
- ^ Sensitivity of the Australian Monsoon to insolation and vegetation: Implications for human impact on continental moisture balance, Geological Society of America
- ^ Australian rivers 'face disaster', BBC News
- ^ Australia faces worse, more frequent droughts: study, Reuters
- ^ Metropolis strives to meet its thirst, BBC News
- ^ "East Africa's drought: A catastrophe is looming". The Economist. September 24, 2009.
- ^ "Kenya drought sparks deadly clashes". ABC News. September 21, 2009.
- ^ "Kenya Devastated by Massive Drought". PBS NewsHour. October 13, 2009.
- ^ "Lush Land Dries Up, Withering Kenya’s Hopes". The New York Times. September 9, 2009.
- ^ Guns, Germs, and Steel by Jared Diamond 1997, pgs 308-309
- ^ Sergio M. Vicente-Serrano & José M. Cuadrat (2007-03-14). "North Atlantic oscillation control of droughts in north-east Spain: evaluation since 1600 A.D.". Climatic Change 85 (3–4): 357–379. doi:10.1007/s10584-007-9285-9. https://www.cfa.harvard.edu/~wsoon/ChristopherMonckton08-d/Vicente-SerranoCuadrat07-NAOonNESpainDroughts.pdf. Retrieved 2010-11-23.
- ^ A biblical tragedy as Sea of Galilee faces drought Belfast Telegraph
- ^ Kenya: Deforestation exacerbates droughts, floods
- ^ NOAA Drought and climate change: implications for the West December 2002
- ^ Record rise in wheat price prompts UN official to warn that surge in food prices may trigger social unrest in developing countries
- ^ Fuel costs, drought influence price increase
- ^ Nigerian Scholar Links Drought, Climate Change to Conflict Africa Oct, 2005
- ^ Is Water the New Oil?
- ^ Sunshade' for global warming could cause drought 2 August 2007 New Scientist, Catherine Brahic
- ^ NOAA factsheet, retrieved April 10, 2007
- ^ BBC article on the World Bank loan to save the Aral Sea
- ^ BBC article from 2004 concerning the risk of Kazakhstan losing the lake
- ^ Cloud seeding helps alleviate drought
- ^ BBC's From Our Own Correspondent on khat water usage
 |
Wikimedia Commons has media related to: Drought |
External links
 |
Look up drought in Wiktionary, the free dictionary. |
 |
Wikinews has related news: Drought |
 |
Wikibooks has more on the topic of |
- Water scarcity from FAO Water (Food and Agriculture Organization of the United Nations)
- US Drought Monitor Current U.S. drought conditions
- US Economic Costs of Drought NOAA Economics
- Catastrophic drought is coming back, Brian M. Fagan lecture for the Long Now Foundation (MP3)
|
||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
Translations:
Top
Drought
Dansk (Danish)
n. - tørke, nød, tørst, tørhed
Nederlands (Dutch)
droogte, langdurig gebrek, dorst
Français (French)
n. - sécheresse
Deutsch (German)
n. - Dürre, Trockenheit, Mangel
Ελληνική (Greek)
n. - (μετεωρ.) ανομβρία, ξηρασία, αναβροχιά, λειψυδρία
Português (Portuguese)
n. - seca (f)
中文（简体）(Chinese (Simplified))
干旱, 缺乏
中文（繁體）(Chinese (Traditional))
n. - 乾旱, 缺乏
日本語 (Japanese)
n. - 干魃, 長期の欠乏, 欠乏
العربيه (Arabic)
(الاسم) جفاف, قحط
עברית (Hebrew)
n. - בצורת, יובש
If you are unable to view some languages clearly, click here.
Post a question - any question - to the WikiAnswers community:
Copyrights:
American Heritage Dictionary
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
Read more
Britannica Concise Encyclopedia
Britannica Concise Encyclopedia. © 1994-2012 Encyclopædia Britannica, Inc. All rights reserved. Read more
McGraw-Hill Science & Technology Encyclopedia
McGraw-Hill Encyclopedia of Science and Technology. Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved.
Read more
Oxford Dictionary of Geography
A Dictionary of Geography. Copyright © Susan Mayhew 1992, 1997, 2004. All rights reserved.
Read more
Columbia Encyclopedia
The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2012, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/.
Read more
Word Tutor
Copyright © 2004-present by eSpindle Learning, a 501(c) nonprofit organization. All rights reserved.
eSpindle provides personalized spelling and vocabulary tutoring online; sign up free. Read more
eSpindle provides personalized spelling and vocabulary tutoring online; sign up free. Read more
Random House Word Menu
© 2010 Write Brothers Inc. Word Menu is a registered trademark of the Estate of Stephen Glazier.
Write Brothers Inc.
All rights reserved.
Read more
Bradford's Crossword Solver's Dictionary
Collins Bradford's Crossword Solver's Dictionary © Anne Bradford, 1986, 1993, 1997, 2000, 2003, 2005, 2008
HarperCollins Publishers
All rights reserved.
Read more
Wikipedia on Answers.com
This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article Drought.
Read more
