The causes of drought are complex with some locations more vulnerable than others — Edexcel GCSE Geography A
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The causes of drought are complex with some locations more vulnerable than others explained
The causes of drought are complex with some locations more vulnerable than others covers 3 specification points, including A.
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Characteristics of arid environments… and Meteorological, hydrological, and human…. Open a point below for its explanation and revision guidance.
a. Characteristics of arid environments compared to the extreme weather conditions associated with drought.
This statement asks you to set the characteristics of arid environments against the extreme weather conditions linked to drought. Arid environments are permanently dry places with very low, unreliable rainfall, high evaporation, high temperatures and sparse vegetation. Their dryness is a long-term feature of the climate. Drought is a temporary extreme weather condition: a period when rainfall falls well below the normal level for a location, often after a sustained dry spell. Method: describe the arid characteristics first, then contrast them with drought. Note that drought can affect wetter regions as well, whereas an arid environment is always dry. A semi-arid example such as the Sahel shows how an arid setting can experience a drought episode that causes crop failure.
b. Different causes of the weather hazard of drought: meteorological, hydrological, and human (agricultural, dam building, deforestation).
This statement asks you to identify and explain the different causes of drought. Meteorological causes are atmospheric, such as reduced precipitation linked to persistent high pressure, subsiding air and blocking systems that prevent rain-bearing winds from reaching an area. Hydrological causes concern water stores: falling river flows, lower reservoir levels and reduced groundwater, which can deepen a drought once it has begun. Human causes are named in the statement as agricultural practices, dam building and deforestation. Agricultural practices such as overgrazing and over-irrigation deplete soil moisture and water stores. Dams can reduce the flow of water downstream. Deforestation lowers transpiration and weakens the recycling of moisture into rainfall. Method: name the cause type, then explain the mechanism that links it to water shortage.
c. Why the global circulation makes some locations more vulnerable to drought as a natural hazard than others and how this changes over time.
This statement asks why the global circulation makes some places more vulnerable to drought than others, and how this changes over time. Air rising near the equator creates low pressure and the Intertropical Convergence Zone; air sinking around 30° north and south creates high pressure. Sinking air suppresses cloud and rainfall, so areas beneath these subtropical belts, and continental interiors far from moisture sources, are more prone to prolonged dry spells. Vulnerability changes as circulation cells shift with climate change and El Niño and La Niña alter Pacific rainfall, so a region may face drought in some years and not others.
Your focus
- Identify three characteristics of arid environments from a set of options.
- Distinguish permanent aridity from temporary drought in a set of descriptions.
- Select the option that correctly contrasts arid environments with drought conditions.
Show all 9 objectives
- Classify causes of drought as meteorological, hydrological or human from a list of examples.
- Identify the mechanism linking deforestation or dam building to reduced water availability.
- Select the option that correctly names the cause type for a given description of drought.
- Explain how subsidence in subtropical high-pressure belts suppresses rainfall.
- Identify locations that are more vulnerable to drought because of global circulation patterns.
- Describe how circulation shifts and ENSO variability change drought vulnerability over time.
The causes of drought are complex with some locations more vulnerable than others exam tips
Marking Points
- Identifies very low and unreliable rainfall as a defining characteristic of arid environments.
- Explains that high evaporation and high temperatures increase water loss in arid areas.
- Recognises sparse vegetation and limited soil moisture as typical arid features.
- Distinguishes arid environments as permanently dry climates from drought as a temporary extreme weather condition.
- Contrasts drought, a departure from normal rainfall, with the consistent dryness of arid regions.
- Uses a named example to show how arid conditions and drought episodes differ.
- Identifies meteorological causes as atmospheric factors, such as reduced precipitation linked to persistent high pressure.
- Explains hydrological causes as declining river flows, reservoir levels and groundwater that reduce water availability.
- Describes agricultural causes, such as overgrazing or over-irrigation, that deplete soil moisture and water stores.
- Explains that dam building reduces downstream river flow and alters water availability for communities.
- Links deforestation to reduced transpiration and weaker moisture recycling, so less water returns to the atmosphere as rain.
- Distinguishes natural atmospheric causes from human causes and states which type each cause belongs to.
- Explains that air sinking in the subtropics around 30° north and south creates high pressure that suppresses cloud and rainfall.
- Links descending air to drought by describing how subsidence inhibits convection and precipitation.
- Identifies continental interiors far from moisture sources and rain-shadow areas as locations more vulnerable to drought.
- Describes how shifts in circulation cells or El Niño and La Niña variability change which regions receive rainfall from year to year.
- Uses a named example region and a clear causal chain rather than listing locations without a mechanism.
Examiner Tips
- 💡Read each option against both halves of the statement before choosing an answer.
- 💡Eliminate any option that describes drought as a permanent climate feature.
- 💡Check that the characteristic named belongs to arid environments rather than to a drought event.
- 💡Check each option against the three named cause types before selecting an answer.
- 💡Eliminate options that attribute drought only to human activity when a natural atmospheric cause is also present.
- 💡Match each mechanism in an option to the correct cause, such as transpiration to deforestation.
- 💡Structure each answer as cause, then location, then effect: name the circulation process, the place it affects, and how that produces drought.
- 💡Use one clear example, such as a subtropical or continental region, and explain its mechanism rather than only naming it.
- 💡For the change-over-time element, distinguish long-term shifts in circulation from year-to-year variability such as El Niño and La Niña.
Common Mistakes
- Confuses an arid climate with drought, treating a permanently dry region as one experiencing a temporary shortage; correct this by stating that aridity is long-term and drought is a departure from normal conditions.
- Describes arid environments only by their landscape, omitting climatic features such as low rainfall and high evaporation; include the climate characteristics that define aridity.
- Assumes drought only occurs in arid places, overlooking that it can affect wetter regions; correct this by stating that drought is judged relative to the normal rainfall of each location.
- Lists features of both arid environments and drought without linking them, so the comparison the statement requires is missing; link each feature directly to the drought conditions.
- Treats hydrological drought as the only cause, overlooking the atmospheric shortage that usually begins the sequence; correct this by recognising the meteorological cause as the starting point.
- Describes dam building as creating drought everywhere, without specifying its effect on downstream flow; correct this by stating that dams reduce water available downstream.
- Lists deforestation as a cause of rainfall loss without explaining the mechanism; correct this by explaining reduced transpiration and moisture recycling.
- Gives human causes without naming the specific practice, such as agriculture, dam building or deforestation; correct this by naming each one precisely.
- Confuses the Intertropical Convergence Zone with the subtropical high-pressure belts; correct this by stating that the ITCZ is a low-pressure rising zone near the equator.
- Treats all deserts as drought-prone for the same reason and ignores the global circulation; correct this by linking vulnerability to atmospheric processes at a specific location.
- Describes drought simply as a lack of rain without explaining why certain locations are vulnerable; correct this by connecting the circulation mechanism to the place.
- Attributes all change over time to human activity alone and omits shifts in circulation; correct this by naming climate change and ENSO variability as causes of change.