The causes of drought are complex with some locations more vulnerable than others — Edexcel GCSE Geography

Drought is a prolonged period of abnormally low rainfall, leading to a shortage of water. It is a complex natural hazard because its causes are not solely meteorological; they are influenced by a combination of climatic, hydrological, and human factors. Some regions are inherently more vulnerable due to their geographical location, such as those in subtropical high-pressure belts (e.g., the Sahara) or rain shadow areas. Understanding this complexity is crucial for predicting, managing, and mitigating drought impacts.

The causes of drought can be categorised into meteorological (lack of precipitation), hydrological (low river flows and groundwater), and agricultural (soil moisture deficits). Human activities, such as over-abstraction of water for irrigation, deforestation, and climate change, can exacerbate natural drought conditions. For example, the Sahel region of Africa experiences drought due to a combination of shifting ITCZ patterns, land degradation, and population pressure. Vulnerability varies because of differences in economic development, infrastructure, and adaptive capacity.

This topic fits into the wider Edexcel GCSE Geography syllabus under 'Hazardous Earth' and 'Development Dynamics'. It links to climate change, water security, and sustainable resource management. Students should appreciate that drought is not just a physical event but a socio-economic one, where the poorest communities often suffer most. Mastering this concept helps in understanding global inequalities and the need for integrated water management strategies.

• →Meteorological drought: caused by a persistent deficit in rainfall due to atmospheric circulation changes, such as El Niño or shifts in the ITCZ.
• →Hydrological drought: occurs when low rainfall reduces river flows, reservoir levels, and groundwater recharge, often lagging behind meteorological drought.
• →Agricultural drought: when soil moisture is insufficient to support crops, often due to a combination of low rainfall and high evaporation rates.
• →Vulnerability: the degree to which a population is at risk, influenced by factors like poverty, reliance on rain-fed agriculture, and lack of water storage infrastructure.
• →Human exacerbation: over-abstraction of groundwater, deforestation (reducing evapotranspiration), and climate change (increasing temperatures and altering rainfall patterns) can worsen drought severity.

• Characteristics of arid environments compared to extreme weather conditions associated with drought
• Meteorological causes of drought
• Hydrological causes of drought
• Human causes of drought (agricultural, dam building, deforestation)
• Role of global atmospheric circulation in creating vulnerability to drought
• Temporal changes in drought vulnerability

• 💡Ensure you can distinguish between the different types of drought causes (meteorological, hydrological, human)
• 💡Use the concept of global atmospheric circulation to explain why specific regions are more prone to drought
• 💡Be prepared to discuss how vulnerability to drought changes over time
• 💡Use specific terminology when describing the human impact on drought (e.g., deforestation, dam building)
• 💡Use specific case studies (e.g., California drought 2012-2016, Sahel drought 1970s-80s) to illustrate causes and vulnerability. Mention both physical and human factors to show complexity.
• 💡Define key terms like 'meteorological drought' and 'vulnerability' in your answers. This demonstrates precise understanding and gains definition marks.
• 💡Link drought to wider themes: climate change (increasing frequency), water security (conflict potential), and sustainable development (SDG 6). This shows synoptic thinking and impresses examiners.

• Confusing meteorological drought with hydrological drought
• Failing to link global atmospheric circulation patterns to specific drought-prone locations
• Overlooking the human-induced factors (e.g., deforestation or dam building) that exacerbate drought conditions
• Generalizing drought causes without considering the complexity of the hazard
• Misconception: Drought is only caused by lack of rain. Correction: While lack of rain is a primary cause, human activities like over-irrigation and deforestation can trigger or worsen drought, even in areas with normal rainfall.
• Misconception: All droughts are the same. Correction: There are different types (meteorological, hydrological, agricultural) with varying timescales and impacts. For example, a short-term meteorological drought may not immediately cause agricultural drought if soil moisture is adequate.
• Misconception: Drought only affects hot, dry countries. Correction: Drought can occur in any climate, including the UK (e.g., 1976 and 2018). However, the impacts are more severe in regions with low adaptive capacity.