tectonics + enso

The hazard risk equation is as follows:

Risk (R) = (hazard (H) x vulnerability (V)) / capacity to cope

a disaster occurs when it actually causes an impact

Capacity to cope means a communities resilience in coping with a hazard

Factors that increase vulnerability:

inequality (unequal access to housing, education, health, and jobs)

Poor governance, corruption, lack of preparedness, planning, and regulations

Older, young people and women(?) are disproportionately affected by disasters

Highly populated areas

Rapid urbanisation

Low accessibility

Weak buildings and infrastructure (linking to preparedness)

PAR model:

root causes: limited access to power and resources, poor political and economic systems

Dynamic pressures: lack of skills, training, and investment , lack of free press, rapid population growth, urbanisation, and deforestation, high debt.

Unsafe conditions: fragile environment, economy and society, poor quality, low income housing

These two phenomena are part of the ENSO (El Niño Southern Oscillation) cycle.

1. Normal Conditions (The Baseline)

To understand the changes, you must first know the "normal" state of the Pacific:

• Winds: Strong Trade Winds blow East to West (from South America toward Australia).

• Water: These winds push warm surface water toward Australia/Indonesia, creating low pressure and heavy rain.

• Upwelling: In South America (Peru), cold, nutrient-rich water rises from the deep to replace the warm water pushed away. This creates high pressure and dry weather.

2. El Niño (The "Warm" Phase)

• The Change: Trade winds weaken or reverse direction (blowing West to East).

• The Shift: The pool of warm water shifts back toward South America.

• Impact on South America (Peru/Ecuador):

◦ Low pressure moves in, leading to extreme rainfall and flooding.

◦ The cold upwelling stops, killing off fish stocks (economic impact).

• Impact on Australia/South-East Asia:

◦ High pressure moves in, leading to severe drought and bushfires (e.g., Australia’s "Big Dry").

◦ Water Insecurity: Reservoirs dry up, and crop yields fail.

3. La Niña (The "Extreme Normal" Phase)

• The Change: Trade winds become exceptionally strong.

• The Shift: Warm water is pushed even further West, piling up around Australia/Indonesia.

• Impact on Australia/South-East Asia:

◦ Extreme low pressure leads to catastrophic flooding and tropical cyclones.

• Impact on South America:

◦ Extreme high pressure leads to even drier conditions and colder-than-usual sea temperatures.

4. Why it matters for Water Insecurity (A-Level Context)

• Teleconnections: ENSO events don't just affect the Pacific; they have global "knock-on" effects (e.g., El Niño can cause weaker monsoons in India and droughts in Ethiopia).

• Predictability: While we know the cycle happens every 3–7 years, its intensity is hard to predict, making it difficult for farmers to plan for water storage.

• Climate Change: Scientists are debating whether global warming is making El Niño events more frequent and more intense, which would lead to more "permanent" water insecurity in the Southern Hemisphere.