Heat is not just about hardware - it's about people
By Simone Sandholz
What does the combination of growing urbanization and aging populations mean for heat risks as the world grows hotter?
In the future we will see more heatwaves like the one we are experiencing right now. Ongoing urbanization processes and increasing surface temperatures due to climate change result in increased heat stress risk in many urban areas around the world. Particularly densely built-up urban areas are prone to urban heat island effects where temperatures hardly cool down over night.
At the same time societies are changing. Populations are ageing and the elderly suffer severely from heat stress. Therefore, we are looking at a growing group of highly vulnerable people and a stressor that is becoming more frequent and more intense.
With growing urbanization, people become more mobile and traditional family and community structures become less important. Community cohesion is weakening and people are less inclined to lend each other a hand during critical times, for example during a heatwave when you might need to rely on your family or friends to let you stay over if their place is cooler, or on your neighbors to take over the grocery shopping.
Overall, high temperatures will have a negative effect on health. Densely built-up urban areas tend to heat up and maintain heat more than the surrounding rural areas; a phenomenon called urban heat island effect. Vulnerable groups such as the elderly, young children, people with chronic diseases or low-income households are likely to suffer most.
What we are also seeing with the current heatwaves is that residents of cities or countries that are not used to heat stress are more vulnerable, as they have less experience with how to react appropriately, by for example adapting working hours, limiting outdoor sports activities or installing shading elements in apartments.
This is illustrated by the example of Montreal in Canada, where 52 people died following a 9-day heatwave in early July. In Germany, the heatwave of 2003 resulted in nearly 7,000 deaths and many heat-related illnesses due to heat stroke, dehydration, and cardiovascular disease.
So in short, heatwaves represent an increasing threat to cities in both the Northern and Southern hemispheres. Yet, not enough is done about it. City authorities are aware of heat as a topic, but they struggle to address it.
Identifying and implementing measures to counteract urban heat stress is challenging for decision makers. Heatwaves affect large regions, and any counter measures need to be coordinated across many different sectors.
It is also often easier for local authorities to mobilize resources for other types of extreme weather events such as heavy rainfalls, where impacts are more immediate and easily visible, whereas the health impacts or even fatalities related to heatwaves among urban populations may occur only after a heatwave has ended.
A strategy for reducing heat in already built-up areas, such as densely populated cities, are more green and open spaces including small-scale greening of roofs and facades. Cities that have recognized this already are for example the city of Melbourne, which wants to double its tree canopy until 2040, or the city of Chicago that introduced green infrastructure projects like permeable pavements and green rooftops, providing benefits for heat reduction and storm water management in its Climate Action Plan.
Tragically, many cities in developing countries are now losing existing public green infrastructure such as ponds and opens spaces due to ongoing urbanization and densification. In an urban worst case scenario only the wealthy can still afford green spaces, as they live in higher-income areas with more parks and are able to afford bigger living spaces with yards or outdoor areas, while marginalized groups lose access and thus cannot benefit from positive impacts on risk reduction, health and well-being.
In principle, we have to realize that adapting cities to heat is not only about urban “hardware” but also about the people and their behavior. Internationally, some cities have already taken this up, among them NYC with its “Beat the Heat” initiative that explicitly includes a community assistance component that encourages people to check in on their neighbors and support individuals that are especially susceptible to heat stress. In addition they provide helpful tips and information on local resources, such as the location of cooling centers.
A simple measure would be to make use of already existing social initiatives, such as sports clubs, senior citizens circles or book clubs, by adding activities to support vulnerable community members during heatwaves. In addition we need more awareness campaigns, not only for the most vulnerable but also for those who can offer support.
Strengthening community ties cannot be the only solution for heat stress, but such initiatives can be implemented short-term and they can be extremely effective. We need to think more about this and we need to do it right now.