Who is most at risk from a disaster?│ The Science of Disasters with Ilan Kelman

Are we more vulnerable to disasters living in cities? Or are they worse on islands, coasts, in mountainous areas? Let's find out in this episode of the Science of Disasters. Don't forget to subscribe to keep up with the series as a whole.

The scale of a disaster is defined by its impacts: the greater the number of people who are affected significantly, the larger a disaster is assumed to be. But are people any more vulnerable for living in larger or smaller communities? Let's look at a small island as an example.

Before its volcano began to rumble in 1995, the Caribbean island of Montserrat had a population of around 12,000. Up to twice this number was killed during the earthquake of 26th of January 2001 in Gujarat, India. If we consider only the total numbers, then the disaster in India far surpasses anything which could ever afflict Montserrat. Conversely, India can draw on the resources of over a billion compatriots to assist. Since 1995, every resident of montserrat has been directly affected by the volcano, and practically all of Montserrat's pre-eruption infrastructure has been severely damaged or entirely destroyed. In 1997, hot ash and gas clouds called pyroclastic flows barreled down the volcano slopes, killing 19 people. This number is obviously small compared to the fatalities in the Gujurat earthquake. Yet, as a proportion of the Montserrat population affected, it would be equivalent to more than one million people dying in India.

Let's now look at the effect of population density. We often hear that moving to cities creates vulnerabilities and that urbanisation, particularly along coasts, is a major cause of disasters. The reality, as with all the other factors of vulnerability, is more complex. Urbanisation implies increasing populations are concentrated in a comparatively small area, so more people are affected by hazard in that area. Epidemics can rage through dense populations, potentially worsening the impact from the hazard, in this case, microbial pathogens. But high population numbers and densities have another side: more people are available nearby to assist quickly.

In many countries, cities have the best equipped, most experienced and fastest responding emergency, health and logistics services. These all help to prevent and deal with disasters unless they are put out of action in the disaster, a situation which can be avoided through readiness and practice. Similarly, if natural hazards occur regularly in a place, then we will be more used to them and hopefully more inclined to prepare for them and know how to deal with them, irrespective of population numbers, population densities, urbanisation or the hazard's characteristics.

Even coasts, often said to be the most dangerous locations, do not necessarily have worse hazards than inland regions because tsunamis, waves, storms and changing water levels affect fresh water areas too, such as a rockslide into a lake or a river swollen with runoff.

If moving to a coast takes us away from mountain hazards such as volcanic eruptions and avalanches, then the balance of hazards might lessen. A city's design also affects both hazards and vulnerabilities. The layout can inhibit or support evacuation, given that areas with more people could be harder to empty if large population numbers need to negotiate tight escape routes. All areas (urban, rural and those in between) have vulnerabilities and abilities to tackle those vulnerabilities.

Vulnerability by numbers does exist through urbanisation, population densities and population numbers, but so, conversely, does safety in numbers, through faster emergency response and better facilities and organisation. So, it is up to us to make the right choices to create or reduce our vulnerability, irrespective of the numbers.

How does a country's ideology influence whether a disaster occurs? Does it make things better or worse? I'll be exploring this question in our next episode of the Science of Disasters. Don't forget to subscribe to keep up with the series as a whole.