Droughts can have severe consequences, as seen in 2003 when 20 million people lacked food during a drought in Ethiopia. There are three main types of drought: meteorological, agricultural, and hydrological. Droughts are caused by factors like high pressure systems that reduce rainfall, oceanic/atmospheric weather cycles like ENSO, and human activities such as poor farming practices.

1. HAZARD #3: DROUGHTS
20 million people lacked food during the 2003 drought in Ethiopia
Drought: extended period of dry weather leading to extremely dry conditions
• “Meteorological drought” = due to prolonged period with less average rainfall
• “Agricultural drought” = drought due to poor agricultural planning (soil
erosion, water usage exceeding carrying capacity) when not enough water is
available for the type of agriculture used in a particular region
• “Hydrological drought” = due to water reserves (aquifers, lakes, etc) slowly
falling below average (ex: Aral Sea in Kazakhstan)

2. CHARACTERISTICS OF DROUGHTS; THREE TYPES OF DROUGHTS
CASE-STUDIES IN TEXTBOOK p.208:
• Europe (2003)
• Horn of Africa (2003)
Compare and contrast the causes and consequences of these two droughts in 2003

3. CHARACTERISTICS OF DROUGHTS: DOMINANT IMPACT TYPES

4. CHARACTERISTICS OF DROUGHTS: CAUSES
• HIGH PRESSURE SYSTEMS:
Increased aridity can be caused by high pressure systems (= prevents upward
condensation over oceans and cloud formation), particularly if over continental
masses (less moisture available) (ex: less than average rainfall in the Horn of Africa
in 2011 due to persistent high-pressure anticyclone over the region)
• OCEANIC / ATMOSPHERIC WEATHER CYCLES:
ENSO (El Niño Southern Oscillation) creates cyclic droughts in Australia and
Americas: cyclic warming (El Niño) of the Eastern Pacific Ocean disrupting usual
wind/current patterns and resulting in droughts in Australia/rainfall in Mexico/Peru.
El Niño is usually followed by La Niña, cooling of the Pacific resulting in opposite
consequences (dry eastern coastlines, wet western coastlines)
• HUMAN ACTIVITY:
Poor farming techniques, excessive irrigation, deforestation, erosion, river
diversions, etc

5. DROUGHTS: SPATIAL DISTRIBUTION OF PERMANENTLY ARID REGIONS
Explain the permanent aridity in the following regions:
• Kalahari and Australia
• Takla Makan and Great Basin
• Atacama and Namib

6. NATURAL AND HUMAN CAUSES OF DROUGHTS
1. Describe the consequences of
the ENSO (El Niño Southern
Oscillation) on each side of the
Pacific ocean
2. Referring to named examples,
suggest other human factors
which may contribute to
creating/increasing droughts