What this lesson teaches
I can explain climate risk as the mix of hazard, exposure and vulnerability, and why it differs between places.
Syllabus K329, Topic 3.3, Key Question 2. Why do climate risks vary across places?
Make a guess
A hospital sits on a floodplain. The council moves it to higher ground. Which part of flood risk has changed?
- Exposure, because it is out of the water's reach.
- Vulnerability, because the building is now stronger.
- The hazard, because floods will now be smaller.
- Nothing, because the town still floods.
Show the answer
Exposure, because it is out of the water's reach.
Moving the hospital puts it where the flood cannot reach. The hazard is unchanged, and strengthening the old building would have reduced vulnerability instead.
Risk depends on the hazard, who or what is in its path, and how easily they can be harmed.
A hazard is an event or trend that could cause harm, such as a flood or rising sea level. Exposure means people, livelihoods, buildings or ecosystems are where the hazard can reach them. Vulnerability means how easily they are harmed and how limited their ability is to cope or adapt. Together, these make up risk: the chance of losing lives, property or ecosystems.
Fast and slow hazards need different preparation. A cyclone or flash flood strikes in hours or days. Sea-level rise and long droughts build up over years. Slow hazards can make fast ones worse: rising seas make a familiar storm more damaging, and repeated droughts use up savings and water reserves.
Location shapes exposure. Low coasts face rising seas and storm surges. Dry areas face water shortages. Building on floodplains increases exposure, while moving a facility away reduces it. Putting more valuable property in a hazard zone can raise possible money losses, even if protection improves.
Vulnerability depends on housing, age, health, income, water and food reserves, healthcare and how well institutions work. Warnings, accessible shelters and social support help people cope. But a warning does little if someone cannot understand it or has no way to leave.
Identify which part of risk a measure changes. Moving a hospital out of a floodplain reduces exposure. Strengthening it reduces vulnerability. Neither stops the storm. Risk is not one fixed formula; it depends on real local conditions.
- Hazard
- Something that could cause harm.
- Exposure
- Being in the hazard's path.
- Vulnerability
- How easily harmed, and how well people cope.
Step by step
Hazard
What could cause harm, and where?
Exposure
Who or what is in its path?
Vulnerability
How easily could they be harmed?
Real examples to use
Cyclones in Bangladesh
The Bhola cyclone of 1970 killed around 300,000 people. After Bangladesh built cyclone shelters and warning systems, Cyclone Sidr, a powerful storm in 2007, killed about 3,400.
Worked example: Two coastal villages
Both face the same storm surge. One has raised homes, good shelters and transport to leave. The other has weak homes and few ways out. The hazard and exposure are similar, but vulnerability makes their risks very different.
Watch out for this
A wealthy place has no climate risk.
Wealth pays for protection, but high exposure, unequal access and extreme events can still cause big losses.
Check your understanding
Which action most directly reduces exposure to coastal flooding?
- Build a new hospital on land outside the flood zone.
- Train hospital staff but keep the hospital where it is.
- Measure the storm more accurately and do nothing else.
Show the answer
Build a new hospital on land outside the flood zone.
Yes. Moving out of the hazard's path cuts exposure.
Check your understanding
Cyclone deaths in Bangladesh fell from around 300,000 in 1970 to about 3,400 in 2007. What mainly explains this?
- Lower vulnerability, through shelters and warnings.
- Fewer people lived on the low coast by 2007, after many moved inland.
- Weaker cyclones hit Bangladesh after 1970.
Show the answer
Lower vulnerability, through shelters and warnings.
The hazard remained; people were better protected.