Wetlands vary widely because of r__egional and local difference__s in: Between 300 and 400 million people live close to - and depend on - wetlands.

This is constantly changing. Their customer service is outstanding, never left a query unanswered. California), Reduced stream-flow and groundwater levels which decrease because of reduced inputs of precipitation and continued high rates of evaporation. Death of people due to dehydration and starvation. Check out, please HelpWriting.net. My brother found Custom Writing Service ⇒ www.HelpWriting.net ⇐ and ordered a couple of works. However, droughts are becoming more frequent and more severe.

In a non-El niño year, the trade winds blow from east to west along the equator, The air pushes the warm water westerwards, Warm, moist air rises, cools and condenses, forming rain clouds, The trade wind pattern is disrupted - it may slacken or even reverse and this has a knock-on effect on the ocean currents. In 2006, a 1-in-1000-year drought event had nationwide effects which commenced in the Murray-Darling basin –Australia’s agricultural heartland- in Australia’s south east. The severity of the drought depends on the amount of time that a region receives below-average precipitation.. For example, a few weeks without rain could stress a farmer’s crops during the growing season.
Droughts occur when there is abnormally low rainfall for an extended period of time. Reservoirs fell to around 40% of their capacity despite advanced water supply schemes which are designed to withstand hydrological drought. The frequency and severity of hydrological drought is often defined on a … The cooling of these waters is known as the La Nina (Little Girl). Although droughts are a natural phenomena human actions may worsen their effects: Rapid population growth resulting in increased pressure on natural resources including water.

They lie somewhere in the complex interactions between atmosphere, oceans, cryosphere, biosphere and the land, which produces the climates of the globe. The cold front (which travels quickly) catches up with the warm front. Droughts can range from short-term and localised precipitation deficits to longer-term trends that are part of climate change. The impacts on Australia’s food supply was disastrous as farmers rely on water to irrigate crops and feed livestock. Check out Adapt — the A-level & GCSE revision timetable app.

The most dominant theory is the El Nino effect with some experts even linking droughts to volcanic eruptions. Air circulation and weather patterns also cause drought. Good luck! See our Privacy Policy and User Agreement for details. Lastly, drinking and tap water shortages lead to socioeconomic drought. Accordingly, drought is a natural event arising due to less precipitation than expected thus defining the intricacies witnessed when the demands for water supply are higher than the available water for some activity, humans, or the environment. Agriculture in the Sahel is exclusively rain-fed making it very vulnerable to drought. Although many theories have been put forth to explain the cause of droughts not much is known. Crops can become toxic due to an increase in aflatoxins especially to animals. ZIMSEC O Level Geography Notes: Weather Hazards: Drought In general terms drought is caused by a general shortage of precipitation over an extended period of time usually the rain season resulting in water shortages for both human and natural activities. Check the source HelpWriting.net This site is really helped me out gave me relief from headaches. Droughts are often associated, but should not be confused with, famine which is an extreme shortage of food for part or most of the population. Hydrophytes colonise the area and nutrient rich soil is created. Agricultural drought is a soil moisture deficit. Drought & Desertification. Human factors do not cause drought but act like a positive feedback loop, enhancing the impacts of drought in the Sahel. Influence on the Natural Greenhouse Effect, typically have a long period of onset, which makes it difficult to determine whether a drought has begun or whether it is just a dry period. Rural population densities the Sahel has doubles every 20-30 years; outstripping food productions. Image by Missouri.edu. Under ‘normal’ conditions the mean annual rainfall varies from 100mm on the northern edge, to 800mm along the southern margins. All you need to know about the June 2020 results, Click to share on Twitter (Opens in new window), Click to share on Facebook (Opens in new window), O Level Computer Science: Software: Operating Systems: Personal Computers, O Level Computer Science: Software: Operating System, O Level Computer Science: Hardware: Point Of Sale Terminal, O Level Computer Science: Hardware: Automated Teller Machine, O Level Computer Science: Hardware and Software: Introduction. Task 2 - Studying the drought map above carefully, complete the following iGCSE style exam question: Describe the distribution of severe to exceptional drought events.
There are two main types of weathering: chemical and physical. ENSO stands for __E__l __N__iño-__S__outhern __O__scillation, This complex weather phenomena can have impacts on global weather and climate for 9-12 months (some prolonged events can last for years). Farmers can make use of insurance schemes. The direction in which the shapes point is the direction in which the front is moving. Scribd will begin operating the SlideShare business on December 1, 2020 Air pressure is always trying to become regulated, by moving from high to low pressure - this is what wind is. Natural variability in the climate can cause a temporary decline in supply and stores are not replenished. New schemes to meet water supply are being developed with include costly desalination plants, recycling of grey water (the relatively clean waste water from baths) and more widespread strategies for conservation. The link with El Niño events is well established. Countries in Northern Africa especially western African countries like Somalia and Ethiopia have more frequent droughts some of which last for years. Causes of Drought. Climatic hazards: Key events like El Nino or La Nina help contribute to drought in areas. The region is undergoing a processes of desertification (see fig.1) whereby semi-arid regions are over cultivated, meaning vegetation dried and the land becomes more exposed to erosion. During the__ 1999-2000__ Ethiopian- Eritrean drought about 10 million people needed food assistance. There are major threats to wetlands and other wildlife habitats. Socio economic (famine) drought is a food deficit. Widespread failure of agricultural systems, food shortages develop into famines that have severe social, economic and environmental impacts. Lack of rainfall is often combined with high temperatures, high winds, strong sunshine, and low humidity. Everything you need to know about Human Causes of Drought for the A Level Geography Edexcel exam, totally free, with assessment questions, text & videos. Causes . Because drought is defined as a deficit in water supply, it can be caused by a number of factors. This regular cycle is also punctuated by occasional droughts of greater severity, such as the Big Dry. High pressure or anticyclones = wind travels clockwise in northern hemisphere, Low pressure or depressions = wind travels anticlockwise in northern hemisphere. 2.5 million square kilometres of wetland has been destroyed intentionally. The Sahel region has high variability of rainfall. Air pressure is expressed as ‘millibars’. Crops wilt and there may be a significant reduction in yields. Plant and animal life are similarly affected. More rain, sleet, hail, and snow can occur where there are moist, low-pressure air systems. How can people and places be protected from the effects of tectonic activity, No public clipboards found for this slide. Falling water tables due to ground water being used for domestic and agricultural activities. Australia has the world’s highest per capita water consumption therefore urban centres -such as Adelaide which draws 40% of it’s drinking water from the Murray River- experienced significant shortages. A Level Geography - Causes of Drought - Seneca - Learn 2x Faster … Rainfall deficiency leads to a deficiency in soil moisture and soil water availability which then has a knock on effect on plant growth and reduces biomass. A drought is a period of drier-than-normal conditions that results in water-related problems.The amount of precipitation at a particular location varies from year to year, but over a period of years, the average amount is fairly constant. Practice irrigation using river and ground water.