All subjects · Geography · WGE01 Global Challenges

Predicting hazards and reducing disaster impacts

Edexcel IAL Geography · WGE01 Global Challenges

Monitoring and prediction reduce the impact of some hazards but not others, and a range of strategies can cut losses, although they are not equally available in developed, emerging and developing countries.

Practise this in the app: instant marking and a fix for every mistake. Free, no email needed to start.

Practise this lesson

Prediction and monitoring

Volcanoes: monitoring of earthquakes, ground swelling and gas emissions allows forecasts. At Pinatubo (1991), PHIVOLCS and USGS forecasts allowed evacuations that saved at least 5,000 and possibly 20,000 lives (USGS).
Tsunami: seismographs and ocean sensors detect a tsunami-generating earthquake, and warning centres issue alerts; useful where travel time is long enough.
Tropical cyclones: satellites and forecast models track storms days ahead.
Earthquakes: the time and place of a particular earthquake cannot be predicted; scientists can only give long-term probabilities (such as the USGS 30-year forecast for California).

Strategies to reduce impacts

Warning and evacuation systems, shelters and drills.
Hazard-resistant design: earthquake-resistant buildings, raised homes, cyclone shelters.
Community preparedness: education, volunteers, emergency supplies.
Land-use zoning: keep housing and key services out of the most dangerous zones such as floodplains and lahar paths.
Aid: short-term relief and long-term reconstruction aid.

Bangladesh shows the effect: about 300,000 people died in Cyclone Bhola (1970), about 3,500 in Cyclone Sidr (2007) and around 20 in Cyclone Amphan (2020), after investment in shelters and the Cyclone Preparedness Program (World Bank, 2022).

Unequal availability

Developed countries: can afford monitoring networks, strict codes, insurance and land-use planning, but large economic losses still occur.
Emerging countries: improving rapidly but rapid urban growth may outpace planning.
Developing countries: limited money, informal housing and weaker governance; often rely on aid and community-based schemes, which can be very cost-effective.

The June 2025 examiners noted that answers on cyclone impacts in developing countries rarely used forecasting and warning systems: use them.

Worked example

Calculate the percentage fall in cyclone deaths in Bangladesh from Bhola (about 300,000, 1970) to Sidr (about 3,500, 2007).

Fall = 300,000 - 3,500 = 296,500
296,500 / 300,000 x 100

Answer: About 98.8% fewer deaths.

Key idea: Volcanoes, tsunami and cyclones can be forecast; individual earthquakes cannot. Warnings, design, preparedness, zoning and aid cut losses, but access to them depends on wealth and governance.

Check yourself

Cyclone deaths in Bangladesh fell from about 300,000 (1970) to about 3,500 (2007). Calculate the percentage fall to 1 decimal place.
Show answer
98.8 %. (300,000 - 3,500) / 300,000 x 100 = 98.8%.
Which hazard cannot yet be predicted in terms of exact time and place?
- Tropical cyclones
- Volcanic eruptions at monitored volcanoes
- Tsunami after a detected earthquake
- Earthquakes
Show answer
Earthquakes. Only long-term probabilities are possible for earthquakes.
Preventing new housing on a high-risk floodplain is an example of
- hazard-resistant design
- land-use zoning
- aid
- prediction
Show answer
land-use zoning. Zoning controls where development happens.
Which observation is used to forecast volcanic eruptions?
- Changes in the Saffir-Simpson category
- River discharge
- Swelling of the ground and increased gas emissions
- Sunspot numbers
Show answer
Swelling of the ground and increased gas emissions. Rising magma deforms the ground and releases gas.
Why might a warning system save fewer lives in a developing country than in a developed one?
- People may lack phones, transport or shelters to act on the warning
- Hazards are smaller there
- Warnings are illegal there
- Developing countries have no hazards
Show answer
People may lack phones, transport or shelters to act on the warning. A warning only helps if people receive it and can act.
Explain why hazard-resistant building design is not available to everyone at risk.
Show answer
It is expensive, so poorer people and governments cannot afford it, and in informal settlements building codes are not enforced.. Cost and weak enforcement, especially in informal housing.

Practise with instant feedback

Sources

Last updated 8 November 2026. Spotted a mistake? Tell us.