Small and mid-size, not mega cities, are growing quickest and need protection against extreme events – says a new study

Stuttgart, New York, Kampala, 28th September 2016 – 18 days before the UN conference on Cities (UN-Habitat III) a new study and an article in NATURE by an international team of researchers shows that fast-growing small (populations of 0.3-0.5 million) and medium-sized (0.5 to 5 million) cities, especially in Africa and Asia, are most vulnerable to natural hazards and need more attention. Risk research and political attention in the past has often been given to the growth of mega-cities, but it will be the rapidly growing small- and medium-sized cities where the success or failure of sustainable urban development will be decided.

At Habitat III around 170 countries will adopt the United Nations’ New Urban Agenda calling for governments to make cities more inclusive, sustainable and resilient. Small and medium-sized cities are particularly susceptible to natural hazards and climate change and often have limited capacities to build resilience. Cities like Kampala in Uganda, Niamey in Niger and Chittagong in Bangladesh face a host of pressures that make them especially vulnerable to natural hazards. They are experiencing high relative rates of population growth while combating poverty, poor infrastructure and governance.

It is fitting that the UN Habitat III conference will be held from 17th to 20th October in Quito, Ecuador. In April, the city and nearby Portoviejo and Manta suffered an earthquake that killed more than 660 people and injured at least 10,000. Some 73,000 people were displaced to shelters, camps or host homes. Over 700,000 people needed emergency assistance, such as safe drinking water, improved sanitation and hygiene kits. Three months on 11,000 people still lack basic services (

Such devastation highlights how susceptible many cities are to natural hazards, from river and coastal flooding to drought, heat, storms, earthquakes, tsunamis and landslides.

Prof. Joern Birkmann from the University of Stuttgart says: “In order to minimize human suffering, cities need to be able to anticipate, absorb, recover and learn quickly from adverse events. This requires clear priorities towards the most vulnerable and rapidly growing small- and medium-sized growing cities.”

The fastest growing cities are small and medium-sized, and there are many of them. The populations of medium and small cities around the world will rise by more than 32% (469 million people) between 2015 and 2030, compared with about 26% (203 million people) in large and megacities. For example, just under half (49%) of India’s 100 million new urban residents expected by 2030 will be in mid-sized cities like Agartala and Tirupati. A quarter (26%) will add to the nation’s four megacities – Delhi, Mumbai, Kolkata and Bangalore. The new study and comment in NATURE highlights the 15 countries where the most vulnerable urban population lives are: Afghanistan, Yemen, Haiti, Central African Republic, Niger, Nigeria, Cote d’Ivoire, Mauritania, Liberia, Pakistan, Mali, Iraq, Benin, Togo and Gambia.

On the other hand, strengthening the resilience of small and mid-sized cities offers opportunities. Smaller cities are easier to manage than megacities. Risk reduction and climate change strategies embedded now can expand as cities grow. And the coordination of and dialogues between different groups are more feasible in small cities, says the study.

To assess which countries have the highest urban vulnerability to natural hazards Prof. Birkmann and Dr. Torsten Welle from the University of Stuttgart analyzed the urban populations of 140 countries, including more than 1600 cities above 300,000 inhabitants Based on a standard methodology (Welle et al. 2015), UN and World Bank data was used on urban populations, infrastructure and socio-economic indicators ( and In the absence of local data we used representative national data on insurance coverage, medical services and governance conditions.

Authors of the study and article are Joern Birkmann, director, and Torsten Welle, senior lecturer, at the Institute of Spatial and Regional Planning, University Stuttgart, Stuttgart, Germany; William Solecki, professor in the Department of Geography, Institute for Sustainable Cities, Hunter College, City University, New York, New York, USA; Shuaib Lwasa, associate professor in the Department of Geography, Geoinformatics and Climatic Sciences, Makerere University, Kampala, Uganda; and Matthias Garschagen, head of section at the United Nations University, Institute for Environment and Human Security, Bonn, Germany.

The Nature article and the supplement can be downloaded in online versions at

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