The degree to which a city is vulnerable to humanitarian crises depends on location-specific physical, social, economic and environmental factors. The literature suggests that geographically, cities in Asia are the most vulnerable to natural disasters. Asian cities also experience the most diverse range of natural disasters.
The main causes of urban vulnerability are often inter-related. Those identified in the literature include:
- Physical location: Cities built along the coast, or on fault lines are particularly at risk. An increase in extreme weather events as a result of climate change has exacerbated the existing vulnerabilities of many cities.
- Poor infrastructure: Much of the world’s urban population lives in informal settlements or slums that are particularly vulnerable to natural disasters. These settlements are also at high risk of fire.
- Overcrowding and poor sanitation facilities: The large number of people living in informal settlements with poor sanitation facilities increases the risk of epidemics in urban areas.
- Strategic importance: Cities are of strategic importance in both inter- and intra-state conflicts. As controlling them can be a key priority for warring parties, they often experience insurgency and urban terrorism.
- Radicalisation: This increases the risk of religiously motivated terrorist attacks in urban areas.
There is widespread concern that climate change will increase the number and severity of urban humanitarian crises in the future. Increased food and water shortages in urban areas – a result of droughts caused by rising temperatures – are also predicted. Conflict over resources could lead to increased risk of armed conflict. The nature of conflict is also likely to change, with new forms of conflict, such as urban violence, becoming increasingly prevalent. Rapid population growth is likely to result in an increase in the number of epidemics in urban areas, due to overcrowding and poor sanitation in informal settlements.