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How can cities deal with heat?

Charli Shield Bonn
July 25, 2018

As the world is battling with extreme heat, researchers from the United Nations University in Bonn are going from door to door to find out what it will take for societies to adapt to a hotter climate.

A woman is dancing in a water fountain (photo: picture-alliance/dpa/V.  Bonn-Meuser)
Image: picture-alliance/dpa/V. Bonn-Meuser

Regina Fleischmann and Anna Düssel are door knocking in Bonn's city center. The two are part of a group of surveyors working forthe United Nations University (UNU) in Bonn who are coming to people's homes to speak to them about heat stress.

Led by climate scientist Matthias Garschagen, head of the Institute of Environment and Human Security at the UNU in Bonn, the researchers are investigating people's living conditions and their perceptions of extreme heat. They aim to get answers from 800 residents to find out what it will take for communities to adapt to a hotter climate.

Read more: Germany braces for sweltering temperatures in Europe-wide heat wave

Colder countries are not immune

Although extreme heat might not be a phenomenon normally associated with a Northern European country like Germany, which can get quite cold in winter, it too faces the impact of rising temperatures. 

In 2003, some 7,000 people died in Germany due to the heatwave that swept across Europe and killed some 70,000 thousand people in in total.

Surveyors from the United Nations University in surburban Altstadt in Bonn, German (photo: DW/C. Shield)
Surveyors Fleischmann and Düssel are going from door to door to ask residents about how they perceive heat stressImage: DW/C. Shield

Although a few very hot days may not seem like much, for vulnerable groups like the elderly, the sick, the poor, pregnant women and infants, it could be serious.

Read more: How to prevent cooling from warming up the world

One of the main risks during a heat wave is that many people don't fully grasp the full danger of high temperatures, Garschagen told DW. 

"On the one hand people think 'Yes, heat is something that needs to be taken very seriously,' but at the same time, when it comes to asking if this expectation of heat becoming an increasing risk factor actually changes people's behavior… the picture changes quite drastically."  

Cities battle with 'heat island effect'

Heat waves are a particularly serious trend for cities, which are warming at a higher rate than other parts of the world. This is because of what's known as the "heat island effect." Since urban areas are often covered in asphalt and concrete, they can't hold water like soil and vegetation do, Garschagen said. 

Figures from a recent study by C40, a climate-research organization focused on urban areas, predict that by 2050, more than 970 cities will face average summertime temperature highs of 35 degrees. Right now, only one-third of these cities experience that kind of heat.  

Forest fires rage in Sweden

With the UN predicting that over two-thirds of the world's population will live in cities by 2050, the number of people exposed to extreme heat is set to increase dramatically. As much as 90 percent of the run towards cities will be centered in Asia and Africa. 

How can we adapt to heat waves?

In order to cope with drastic weather changes, many cities will require extensive urban planning adaptations. Garschagen says this could include changing the building materials used in construction, planting more trees, making room for green spaces, and building fresh air corridors. 

But he also cautions that implementing these changes is no easy task. 

"Urban planning can give you technical solutions for what could be done … but the real challenge in urban societies, like here in Bonn, is actually to negotiate with [people] about what they are willing to accept in terms of changes," he told DW.

"For example, is it acceptable to leave certain spaces — that would make perfect slots for future development, where you could make a lot of profit — open for climatic reasons, or not? These societal and political debates — that tends to be the real challenge," he said.

How bad could it get?

Some research suggests that many parts of the world — places in South Asia, the Persian Gulf and Australia, for example — could actually become uninhabitable due to rising temperatures.

"The really, really challenging question is: when do societies start to accept that the set up of our cities as we know it is no longer sustainable in the future?" Garschagen said.

Once the researchers have collected all the data they need, they will be busy over the next few months trying to establish trends in the way city dwellers perceive and react to extreme heat. With this information, they hope they can better prepare the globe for what will most certainly be a hotter future.

Listen to the radio report about the danger of heat waves

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