#12 Urban planning and constraints under the hot climate in Brazil

Published by La rédaction C21

With a significant rural exodus and a territory very sensitive to the effects of global warming, Brazil must reorganize the urban fabric of most of its cities. This requires in particular taking into account very specific problems such as the proliferation of disease vectors or the concentration of labour supply in very limited places. Sergio Myssior, director and partner of Myr Projetos Sustentáveis, answers our questions.

What is the role of urbanism in the fight against climate change?

 

Urbanism has the challenge of rethinking and reinventing cities, because the model of urbanization that has been applied in Brazilian cities is exhausted. In addition to that, over the last few decades a process of intense migration of people from the countryside to the cities (in Brazil we have more than 84% of the population is living in the cities), which was not accompanied by the necessary infrastructure and the concept of sustainability to receive these people, took place in the Brazilian metropolis.

Currently in Brazil and all Latin America this situation directly affects the people with the low income, causing them to live far from the opportunities, thereby creating a model of dispersed urbanization in the metropolis, where it overflows into other cities of lower density, causing a series of negative impacts on both the daily lives of the population and the environment. When people live far from the opportunities, they spend more of their daily journey with commuting movement, also regarding infrastructures and services, the longer are distances the more expensive will for the public sector to provide them.

The environmental impacts linked with the climate change can be seen by the increase of emissions of greenhouse, which are a result of long commuting in means of transportation that are predominantly fossil fuel-powered, both public and individual transport. Other factors that also contribute to emissions such as solid waste management, the long distances make it difficult to create an integrated waste management and sanitation network.

The logic of city growth did not take into account climate change events, which are getting more intense and frequent, such as floods, landslides, heat islands, even disease vectors (dengue and chikungunya). The vulnerability of cities to climate change is very high not only because of the urbanization model, but also because of the lack of infrastructure and decisions taken in the past such as soil sealing.

What the urban solutions to fight against climate change?

 

There are a multitude of solutions that can be applied to promote the quality of life in cities; it depends of what is suitable for each case. In general terms, what needs to be done is to start from a macro or regional scale, in order to have a vision of what are the dynamics, culture, history, landscape aspect, ecological corridors of the site before entering in a more local level or even the actual buildings, in order to be able to connect the landscape and green areas, thus creating a green mesh.

Urban afforestation is an aspect that should be given much attention in the Brazilian urban context, with a regard to the selection of the most adapted species to urban areas in relation to their roots, but also concerning to the aerial issue, that generates a conflict, sometimes difficult to solve. In Brazil most of the wiring of the electrical system is still aerial, as the trees are planted in the alignment of these poles, the trees and the wires come into conflict, making the trees receive a inappropriate pruning, that they can be mutilated. The solutions that can be used are a greater distance from the network creating a garden when possible, another solution that is also being implemented is the replacement of one or two parking places by a draining garden with afforestation that can also be used as a convivial and even pedagogical space, thus bringing an increase in thermal comfort of cities.

Regarding the blue infrastructure formed by the water courses, springs and groundwater present in urban environment, Brazil has negative history of reconciling the blue infrastructure with urban development, it is always important to identify them, preserve them and what is often the case recover them.

Concerning streets and sidewalks it is important to implement solutions to retain rainwater and infiltrate it into natural soil, such as the use of draining floors, draining gardens, natural and forced permeability solutions, which promotes the recharge of aquifers and in moments of intense rain, which are increasingly frequent, are essential. Another solution linked to the drainage system are the underground retention boxes that collect rainwater at peak times, that can be either leaked into the drainage system or be reused in plant irrigation, cleaning, in sanitary systems, it all the depends on the treatment that the water has received.

As for buildings it is important to take into account solar orientation, especially in a tropical country. Currently in Brazil buildings still import an international standard of construction, such as large glass façades and an inadequate solar orientation, thus creating a need for air conditioning system to combat this heat retention. That is why it is important to have a correct solar orientation, in addition to natural ventilation systems so the air conditioning system is used cautiously. Maximizing the use of natural light, LED lamps and timers are also solutions that should be applied to reduce energy consumption, gas emissions and improve users comfort.

The use of vertical gardens and green roofs are also often applied, they are not only solutions that bring thermal comfort, but they also can have a social and economic functions, creating living spaces, urban gardens, which can also be implemented in urban voids.

In relation to energy consumption, at the domestic level the heating of water represents more than half of the Brazilian energy consumption. The implementation of solar water heating is a solution that is already well spread. In addition, photovoltaic panels are starting to be diffused in Brazil, the ANEEL (national electricity agency) allows private producers to sell the energy produced, which is released into the grid and a balance is made between consumption and production.

What are the biggest challenges in the implementation of sustainable projects?

 

Rethinking cities that already have a consolidated structure but also an urgent need to transform its scenario. The majority of Brazilian cities are concerned about the vulnerability to climate change and the effects are already being perceived, phenomena such as flooding, landslides, heat islands and disease vectors can be perceived periodically. Therefore, even after major interventions, it is not possible to fully reverse this situation in a short period of time.

Another relevant challenge is the education of the citizen, Brazil is a signatory country of climate agreements such as the Paris agreement, but these measures are not yet seen in the daily life of the Brazilian citizen, this means for example that people continue to move around in individual transport, using fossil fuel, low use of non-motorized transport, that is just speaking about the area of mobility.

 

Interview conducted by Izadora Alcanflor - Construction21

Moderated by : Clément Gaillard

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