Environmental disasters have different impacts on small towns and large cities

Limited funds and technical capacity make smaller towns more vulnerable to environmental disasters, whereas scale is the main challenge for large cities.

By Elton Alisson  |  Agência FAPESP – Most of Brazil’s small towns with up to 100,000 inhabitants, which comprise half the country’s population, have no institutional funding to adapt to climate change, including higher temperatures and heavier rainfall, or to enhance their resilience and mitigate the impact of natural disasters.

A lack of financial and human resources to address environmental challenges and natural disasters in these smaller towns, which account for 95% of Brazil’s municipalities, makes them more vulnerable to destruction by environmental disasters such as the collapse of a tailings dam in Mariana, in Minas Gerais State, in November 2015.

This view was expressed by Ricardo Ojima, a professor in the Department of Demography & Actuarial Sciences at the Federal University of Rio Grande do Norte (UFRN), in a presentation during the seminar entitled “Finding solutions for urban resilience to nature’s challenges” held on November 28-29 at FAPESP in São Paulo.

The purpose of the event, organized by FAPESP in partnership with the Finnish Funding Agency for Innovation (Tekes), was to foster the development of new scientific collaborations between researchers at São Paulo State and in Finland and to present the results of research that was supported by FAPESP in areas such as urban resilience, meteorology, urban planning and water security.

“If an environmental disaster on the scale of what happened in Mariana had occurred in São Paulo, for example, the number of deaths would certainly have been much larger and it would have affected the functioning of the city but wouldn’t have destroyed it completely,” Ojima argued.

“In a small town like Mariana, an event like the collapse of a tailings dam can mean the end of the town, of its historical and cultural heritage, and of the emotional relationships established with the town by its inhabitants.”

According to Ojima, whose postdoctoral research was supported by a scholarship from FAPESP, more people are exposed to environmental change and disasters in absolute terms in Brazil’s major cities, which have over 500,000 inhabitants each and account for 50% of the country’s total population but only 5% of its municipalities.

However, smaller towns have fewer resources and experience more difficulty with management and technical capacity building to address environmental issues. Ojima stated, “We’re on a knife edge as far as the adaptation of Brazilian urban units to environmental change and resilience to natural disasters is concerned.”

Investment in two situations is required, he explained. Adaptation and enhanced resilience for major cities, where many more people can be affected by a single extreme event, and the development of mechanisms to increase adaptive capacity and resilience in small towns, which can be completely destroyed by a disaster such as the Mariana dam breach.

Increased exposure

One problem that is shared by small towns and large cities is the growing number of inhabitants in precarious dwellings, which contributes to increased exposure to environmental disasters, said Maria Camila Loffredo D’Ottaviano, a professor at the University of São Paulo’s School of Architecture & Urbanism (FAU-USP).

According to data from IBGE’s 2010 census presented by D’Ottaviano, 5.61% of Brazilians live in shantytowns (favelas). Almost one-tenth of these slum dwellers live in São Paulo and another one-tenth live in metropolitan areas.

“IBGE defines favela dwellers as squatter families according to the information given to census officials by heads of household. That means people living in irregularly established but urbanized housing projects around the Guarapiranga and Billings reservoirs in São Paulo aren’t counted as favela dwellers, for example,” D’Ottaviano reported.

If the latter were counted, she added, the proportion of households in precarious dwellings or inappropriate areas of the city would be 30%.

“There are a large number of favelas in the southern part of the city, where Guarapiranga and Billings are located, and in the northern part, on the slopes of the Serra da Cantareira, an environmental conservation area, as well as outlying parts of the east. The situation was far worse in 2010 than in 2000,” she said.

The inhabitants of these vulnerable areas are affected the most by changes in the rainfall regime, for example. Researchers who attended the event stated that this vulnerability derives both from natural weather variability and from increasing urbanization, which exacerbates the “heat island effect” that is caused when surfaces that were once permeable and moist become impermeable and dry, making urban regions warmer than their rural surroundings.

Ongoing urbanization in São Paulo has destroyed what remained of the Atlantic rainforest, coating the soil with asphalt and concrete, which absorb heat but not moisture.

Consequently, the city is warm during the day. At night, the heat that is stored by streets and buildings is released into the atmosphere. Relative humidity is low, and moisture evaporates quickly to form storm clouds.

“There’s a need to study the precise location of the city’s heat islands and the use of green spaces to mitigate the effects of this climate phenomenon on specific parts of the city, such as low-lying areas,” stated Humberto Rocha, a professor at the University of São Paulo’s Institute of Astronomy, Geophysics & Atmospheric Sciences (IAG-USP), during the event.

“We have to produce a great deal of science to clarify issues of scale and identify causes of climate change in cities like São Paulo.”

Connecting the dots

For Paulo Saldiva, a professor at the University of São Paulo’s Medical School (FM-USP), scholars at Brazilian universities already produce a significant number of studies on cities. For example, USP ranks fourth among universities worldwide in terms of the number of articles indexed by the Web of Science and ranks third in studies of cities and health.

The real challenge involves converting the results of these studies into integrated solutions that can be implemented by public administrators, he went on to say.

For this to happen, administrators need to be shown how much they may have to pay if they fail to adopt a proposed solution and the damage that could be done to the population.

“In the Brazilian case,” he stated, “almost all mayors are facing an acute shortage of funds, so we must underscore the future effects and immediate benefits in financial terms.”

Other participants in the event included Carlos Henrique de Brito Cruz, FAPESP’s Scientific Director, Jarkko Wickström, Coordinator for Education, Science & Research Cooperation at the Finnish Embassy in Brazil, and Ari-Matti Harri from the Finnish Meteorological Institute (FMI).