What is the primary difference between a drought and simply a period of no rain?

A drought is defined by a prolonged period of dry weather that is significantly more severe than normal for a specific region, leading to water levels falling below what is needed for people, crops, and ecosystems. Simple lack of rain might be normal for a dry season, but a drought implies an abnormal and impactful deficit.

How do meteorological causes of drought differ from climate change-related causes?

Meteorological causes refer to natural atmospheric phenomena like shifts in weather patterns, monsoon timing changes, or persistent high-pressure systems that directly reduce precipitation. Climate change-related causes, however, are long-term trends like increased global temperatures leading to higher evaporation and more unreliable rainfall patterns, which exacerbate existing meteorological conditions.

What is the distinction between surface water and groundwater impacts during a drought?

Surface water impacts are immediately visible, such as shrinking rivers, lakes, and ponds, affecting direct water access and aquatic life. Groundwater impacts involve falling water tables in aquifers, which are slower to manifest but can lead to wells running dry and long-term depletion of crucial reserves, impacting communities reliant on boreholes.

What is a common misconception about drought onset that can lead to inadequate preparation?

A common misconception is that drought is a sudden event, similar to a flood. In reality, droughts develop slowly over weeks or months, allowing impacts to accumulate gradually. Underestimating this slow onset can delay critical preparedness and mitigation efforts, leading to more severe consequences.

What error might occur if one only focuses on rainfall deficits without considering other factors when assessing drought severity?

Focusing solely on rainfall deficits overlooks the role of increased temperatures and evaporation, which are crucial in determining actual water availability. Even with moderate rainfall, high temperatures can lead to rapid moisture loss, intensifying drought conditions and making the environment drier than precipitation data alone would suggest.

What is a critical mistake in addressing drought impacts that can worsen long-term outcomes?

A critical mistake is to address only the immediate symptoms (e.g., providing emergency food aid) without tackling the underlying environmental degradation. Ignoring issues like soil erosion and desertification means the land's capacity to recover is diminished, making future droughts even more devastating and perpetuating a cycle of vulnerability.

Define 'drought' in the context of environmental management.

Drought refers to an extended period of abnormally low rainfall, leading to a shortage of water for human use, agriculture, and natural ecosystems. It is characterized by its duration, intensity, and spatial extent, and is always relative to the typical climatic conditions of a specific region.

What is desertification and how is it linked to drought?

Desertification is the process by which fertile land becomes desert, typically as a result of drought, deforestation, or inappropriate agriculture. Prolonged drought is a primary driver, causing soil to lose nutrients and structure, vegetation to die, and the land to become unable to support plant life, thus expanding arid areas.

Explain the concept of 'famine' as an impact of drought.

Famine, in the context of drought, is a severe food shortage affecting a large population, leading to widespread malnutrition, starvation, and death. It results from drought-induced crop failures, livestock losses, and subsequent sharp increases in food prices, making food inaccessible to vulnerable communities.

How does climate change intensify drought conditions beyond just reducing rainfall?

Climate change intensifies drought by increasing global temperatures, which leads to higher rates of evaporation from soil, plants, and water bodies. This means that even if some rain falls, the moisture is lost more quickly, effectively drying out the environment faster and exacerbating the impact of any precipitation deficit.

Causes & Impacts of Drought | Cambridge International Examinations IGCSE Environmental Management

Revision Notes

IGCSE

Cambridge International Examinations

Environmental Management

Natural Hazards

Causes & Impacts of Drought

Summary

Droughts are prolonged periods of abnormally dry weather, characterized by a significant deficit in precipitation that disrupts the natural water cycle. They are primarily caused by meteorological factors like shifts in weather patterns and high-pressure systems, with climate change acting as a major exacerbating factor by increasing temperatures and altering rainfall reliability. The impacts of drought are wide-ranging and cumulative, affecting water resources, agriculture, ecosystems, human health, and economies, often leading to severe consequences such as famine, desertification, and increased wildfires.

1. Definition & Core Concepts

A drought is defined as a prolonged period of unusually dry weather that is significantly longer or more severe than what is considered normal for a specific region. It is not merely a lack of rain but rather a condition where water levels fall below the critical thresholds required to sustain human needs, agriculture, and natural ecosystems. This definition highlights the relative nature of drought, as what constitutes a drought in one climate may be normal conditions in another.
Key features of drought include its slow onset and gradual development, distinguishing it from rapid-onset hazards like floods or cyclones. Drought conditions progressively worsen over weeks, months, or even years, allowing impacts to accumulate. Furthermore, droughts affect both surface water sources, such as rivers and lakes, and groundwater reserves, including aquifers, leading to widespread water scarcity.

2. Primary Causes of Drought

The most direct cause of drought is a prolonged lack of precipitation, meaning significantly less rainfall than expected over an extended period. This deficit disrupts the natural water cycle, preventing the replenishment of water sources. Even a few weeks of below-normal rainfall can initiate early drought symptoms, particularly in regions already prone to dry seasons.
Several meteorological factors contribute to reduced rainfall. These include shifts in large-scale weather patterns that divert rain-bearing winds away from a region, or changes in the timing and intensity of monsoons, which are crucial for seasonal rainfall in many parts of the world. Additionally, persistent high-pressure systems can block the formation of clouds and prevent precipitation, leading to clear skies and dry conditions.

3. Climate Change as a Driver

Climate change significantly exacerbates the frequency and severity of droughts globally. Higher global temperatures lead to increased evaporation from soil, plants, and water bodies, meaning moisture is lost from the environment faster than rainfall can replace it. This intensifies dry conditions even in areas that might receive some precipitation.
The warming climate also contributes to more extreme and unreliable weather patterns. Some regions may experience sudden, intense rainfall events and floods in one year, followed by prolonged dry spells or almost no rainfall in subsequent years. This variability makes water management challenging and increases the likelihood of drought. Furthermore, warmer oceans can disrupt established wind patterns and monsoons, altering the distribution of rainfall.

4. Ecological & Agricultural Impacts

5. Socio-Economic & Health Consequences

6. Long-Term Environmental Degradation

7. Interconnectedness of Impacts