Risk, Hazard and Vulnerability

There are numerous environmental (natural) hazards to human life and well-being:

The amount of risk (the possibility that something undesirable will happen) is a function both of the likelihood of a hazard and the vulnerability (openness to harm or damage) of the people involved. This can be expressed as a pseudo-equation (Wisner, Blaikie, Cannon and Davis 2003):

Risk = Hazard * Vulnerability

Use of a truth table with that equation expresses the way in which risk is the confluence of hazard and vulnerability. Assigning the values of zero for low and one for high:


For example:

The Social Construction of Risk

If a tornado occurs in an undeveloped, unpopulated rural area, the consequences to humans are minimal. However, if that tornado occurs in a densely-populated urban area, the consequences can be catastrophic.

This demonstrates how risk is socially-constructed, and how the term "natural disaster" can be considered a misnomer, something Smith (2006) expounds on in greater detail.

While hazards like earthquakes and floods are a function of environmental conditions beyond the control of individuals, vulnerability is a socially-constructed function of human factors like economics, politics, history and values.

For example: while a cyclone is an environmental hazard, the vulnerability of an individual to harm from that cyclone is affected by factors like:

In a broader sense, hazards can also be socially-constructed changes to "nature," calling into question where the boundary should be drawn between the human and the "natural:"