REPORT
Urban areas will have to adapt
Published on January 26th, 2016
Edited on January 28th, 2016
Edited on January 28th, 2016
The implementation of green roofs is one of the most effective resilience measures to combat heat waves in urban areas. This was one of the conclusions of the CLICURB project, which examined the effects of climate change on cities and pointed out some adaptation and mitigation solutions.
“It will only be possible to meet the challenge of climate change if we do so in urban areas”, says Carlos Borrego, researcher at the University of Aveiro (Universidade de Aveiro) and coordinator of CLICURB, a project developed at this same university.
The solution is to increase the resilience of cities with concrete and urgent measures, that range from the expansion of green areas (parks, gardens), the creation of white or green roofs, to the increase of blue areas (ponds, lakes or streams).
According to Carlos Borrego, “urban areas are particularly vulnerable to climate change for several reasons. The most crucial reason is demographic pressure. In 2050, 80% of Europe's population will be living in urban areas. This means more than 36 million people. In Portugal, in the same year, we will have 1.6 million people living in cities, mainly Grande Porto (Greater Porto) and Grande Lisboa (Greater Lisbon)”.
On the other hand, the effects of climate change, such as rising temperatures, mean sea level rising or the risk of flooding, are exacerbated by the cities’ features, namely the urban morphology, the materials used in coatings and buildings, and the activities of the population.
Heat islands: “hell” in the cities
Heat islands are one of the typical phenomena of urban areas and tend to worsen with climate change. A kind of vicious circle is expected in which the temperature increase resulting from climate change (which may be, in some places, of 4ºC by 2050) accentuates the phenomenon of heat islands, which will increase power and water consumption (in a period of expected shortages), and worsen climate change.
The concept of heat islands is different from the concept of heat waves that occur when the daily maximum temperature is 5ºC higher than the average daily value during the reference period, in an interval of at least six consecutive days.
“To understand what a heat island is, just think that urban infrastructures are composed of a very wide range of materials such as asphalt, cement or concrete and other coatings with high heating capacity. These infrastructures receive solar radiation, absorb it and release it at night when the temperature decreases”, explains Carlos Borrego.
However, “the release of heat that was absorbed throughout the day causes the temperature over the city to be higher than the temperature at the same height over the surrounding areas, which are typically suburban or rural. We are talking about more than 2ºC difference between nearby areas, just a few kilometres away”.
This small difference is enough to enable heat waves to transform the cities into a “hell”, causing serious health problems and a countless number of deaths. The result may be unsustainable, with serious environmental, social and economic repercussions.
How to solve it?
If many people are already upset by waves and heat islands, how is the mid-twenty-first century going to be like? What will be the quality of the air that we breathe? Will we be able to act?
Within the framework of the CLICURB project, Carlos Borrego and his team have assessed the impact of climate change and some resilience measures in urban areas, using the city of Porto (Oporto) as a case study.
“We have measured emission flows (including CO2 and water vapour) in urban areas and in rural areas, which allowed us to characterise the heat islands very well. It was absolutely innovative. Such a study had not yet been done in Portugal”.
Next, the researchers identified and tested some resilience factors in future scenarios. The factors tested are essentially of adaptation and mitigation measures to climate change.
Carlos Borrego now challenges local councillors to incorporate these measures in territory planning strategies. “It's just a matter of having the political will to change the development strategies and urban and regional planning”, he says.
Toronto and Copenhagen: follow these examples
In his view, the so-called “solutions based on nature”, such as green parks, are essential to fight the effects of climate change in cities, namely the heat islands.
The expert encourages, also, the creation of green roofs and gives the example of Toronto and Copenhagen. For those who do not want or cannot choose to have the green roofs, the expert advises the so-called “white roofs”. “It is no coincidence that, in the Algarve, the houses have roofs painted white. Solar radiation falls on a white roof and is reflected. Heating is much lower in a concrete roof than in brick. This is a measure that can be immediately implemented. No need to wait 10 or 20 years”, he stresses.
The creation of blue areas is another measure mentioned. “We have, over the last 100 years, made a number of mistakes in the planning of cities, covering the water lines in order to construct major avenues. Today it is known that water pipelines are the worst solution. Just look at Albufeira and see the results. We must allow water lines to take their natural course especially because we will have more extreme events”, he recommends.
These adaptation and mitigation measures have benefits at various levels, particularly in increasing the thermal comfort, reducing energy consumption and, consequently, reducing of emissions of greenhouse gases and improving the quality of the air we breathe.
“Winning” the local authorities and population
The CLICURB group is now presenting these measures to the councils while at the same time trying to “win over the population”. “I have some hope that the councils, knowing that these instruments are available, can begin to do this work locally. There is a wide range of resilience measures that are transversal, but, to give an adequate response to climate change, we need to locate them and thus ensure that local conditions are taken into account”, he warns.
The project ended on 31st December 2015, and may be extended for another two years. It also resulted in an Urban Atlas of Oporto (Atlas Urbano do Porto), a geographic information platform that allows, for example, to analyse the current radiation flows and how increasing green area would be reflected in a decrease in temperature, in addition to the projection of a set of long-term parameters. The website will soon be available, and it can become a working and a decision-making tool for citizens and local councillors, particularly in the fields of water management, agriculture, tourism, energy supply management, human health, and others.
By: Cláudia Azevedo
The solution is to increase the resilience of cities with concrete and urgent measures, that range from the expansion of green areas (parks, gardens), the creation of white or green roofs, to the increase of blue areas (ponds, lakes or streams).
According to Carlos Borrego, “urban areas are particularly vulnerable to climate change for several reasons. The most crucial reason is demographic pressure. In 2050, 80% of Europe's population will be living in urban areas. This means more than 36 million people. In Portugal, in the same year, we will have 1.6 million people living in cities, mainly Grande Porto (Greater Porto) and Grande Lisboa (Greater Lisbon)”.
On the other hand, the effects of climate change, such as rising temperatures, mean sea level rising or the risk of flooding, are exacerbated by the cities’ features, namely the urban morphology, the materials used in coatings and buildings, and the activities of the population.
Heat islands: “hell” in the cities
Heat islands are one of the typical phenomena of urban areas and tend to worsen with climate change. A kind of vicious circle is expected in which the temperature increase resulting from climate change (which may be, in some places, of 4ºC by 2050) accentuates the phenomenon of heat islands, which will increase power and water consumption (in a period of expected shortages), and worsen climate change.
The concept of heat islands is different from the concept of heat waves that occur when the daily maximum temperature is 5ºC higher than the average daily value during the reference period, in an interval of at least six consecutive days.
“To understand what a heat island is, just think that urban infrastructures are composed of a very wide range of materials such as asphalt, cement or concrete and other coatings with high heating capacity. These infrastructures receive solar radiation, absorb it and release it at night when the temperature decreases”, explains Carlos Borrego.
However, “the release of heat that was absorbed throughout the day causes the temperature over the city to be higher than the temperature at the same height over the surrounding areas, which are typically suburban or rural. We are talking about more than 2ºC difference between nearby areas, just a few kilometres away”.
This small difference is enough to enable heat waves to transform the cities into a “hell”, causing serious health problems and a countless number of deaths. The result may be unsustainable, with serious environmental, social and economic repercussions.
How to solve it?
If many people are already upset by waves and heat islands, how is the mid-twenty-first century going to be like? What will be the quality of the air that we breathe? Will we be able to act?
Within the framework of the CLICURB project, Carlos Borrego and his team have assessed the impact of climate change and some resilience measures in urban areas, using the city of Porto (Oporto) as a case study.
“We have measured emission flows (including CO2 and water vapour) in urban areas and in rural areas, which allowed us to characterise the heat islands very well. It was absolutely innovative. Such a study had not yet been done in Portugal”.
Next, the researchers identified and tested some resilience factors in future scenarios. The factors tested are essentially of adaptation and mitigation measures to climate change.
Carlos Borrego now challenges local councillors to incorporate these measures in territory planning strategies. “It's just a matter of having the political will to change the development strategies and urban and regional planning”, he says.
Toronto and Copenhagen: follow these examples
In his view, the so-called “solutions based on nature”, such as green parks, are essential to fight the effects of climate change in cities, namely the heat islands.
The expert encourages, also, the creation of green roofs and gives the example of Toronto and Copenhagen. For those who do not want or cannot choose to have the green roofs, the expert advises the so-called “white roofs”. “It is no coincidence that, in the Algarve, the houses have roofs painted white. Solar radiation falls on a white roof and is reflected. Heating is much lower in a concrete roof than in brick. This is a measure that can be immediately implemented. No need to wait 10 or 20 years”, he stresses.
The creation of blue areas is another measure mentioned. “We have, over the last 100 years, made a number of mistakes in the planning of cities, covering the water lines in order to construct major avenues. Today it is known that water pipelines are the worst solution. Just look at Albufeira and see the results. We must allow water lines to take their natural course especially because we will have more extreme events”, he recommends.
These adaptation and mitigation measures have benefits at various levels, particularly in increasing the thermal comfort, reducing energy consumption and, consequently, reducing of emissions of greenhouse gases and improving the quality of the air we breathe.
“Winning” the local authorities and population
The CLICURB group is now presenting these measures to the councils while at the same time trying to “win over the population”. “I have some hope that the councils, knowing that these instruments are available, can begin to do this work locally. There is a wide range of resilience measures that are transversal, but, to give an adequate response to climate change, we need to locate them and thus ensure that local conditions are taken into account”, he warns.
The project ended on 31st December 2015, and may be extended for another two years. It also resulted in an Urban Atlas of Oporto (Atlas Urbano do Porto), a geographic information platform that allows, for example, to analyse the current radiation flows and how increasing green area would be reflected in a decrease in temperature, in addition to the projection of a set of long-term parameters. The website will soon be available, and it can become a working and a decision-making tool for citizens and local councillors, particularly in the fields of water management, agriculture, tourism, energy supply management, human health, and others.
By: Cláudia Azevedo