Made in the shade

After a sweltering summer, Switzerland is now reeling from the news that it’s in for an exceptionally cold winter. After two years of face masks and travel restrictions, our “post-Covid” world is less idyllic than we imagined. This reveals, among other things, the limits of our urban systems and how urgently we need to rethink our cities and the way we use land more broadly.

It's been hot – too hot – and stifling summer nights are only becoming more common. So far, we’ve been content to blame the densityof urban heat islands, without ever questioning what causes the high temperatures. But urban-development density is only a number.It tells us the ratio of the amount of ground surface to building surface, nothing more. Cities with the same density can look very different from one another.Our dense Swiss cities are here to stay, but we have to rethink them.

One way to dramatically reduce temperatures is through vegetation. On hot summer days, we seek refuge along tree-lined streets. Lausanne has introduced an urban greening initiative, and all cities should follow its example. To achieve this, we must make large swaths of our impervious cities permeable.

Our dense Swiss cities are here to stay, but we have to rethink them.

Diversify energy sources

We’re gearing up for a very cold winter, and unchecked power consumption spells danger for cities. Power is difficult to store. Electric cars need a steady flow: pull the plug and everything stops. The same is true for non-autonomous buildings. If there’s a power shortage, homeowners with solar panels won’t have additional electricity and will be cut off like everyone else.

The answer lies in energy storage and diversification. While imposing a 19°C heating limit is no doubt a good start, most heating systems aren’t electric. A system is only as resilient as its ability to withstand a shock. Depending entirely on electric power – even from renewable sources – is a recipe for disaster.

The pandemic hasn’t transformed city centers so much as it hastened the demise of their commercial activities. The transportation and flow of goods will be top priorities for city planners. Today, the Internet, DHL, FedEx, et al. control nearly all of our purchases.

Pandemics are intrinsically linked to biodiversity loss, meaning it’s more urgent than ever before to recreate natural spaces.

Reclaiming our streets

Urban planners talk about “activating spaces.” But it will take more than just shops and businesses to create vibrant public areas. With commerce out of the picture, our city streets will have to be reimagined as places where people live, not just pass through and shop.

The pandemic also threw up the issue of biodiversity. Pandemics are intrinsically linked to biodiversity loss, meaning it’s more urgent than ever before to recreate natural spaces.

If we focus our efforts on creating green, diverse, people-friendly streets and autonomous buildings, these various shocks could end up being positive overall for our cities. By trading in commercial districts for green spaces and repurposed streets, cities can once again become living, breathing places for its residents to call home.

• This article was published late October 2022 in three local dailies – La Côte (Vaud Canton), Le Nouvelliste (Valais Canton) and Arcinfo (Neuchâtel Canton) – under a joint initiative between EPFL and ESH Médias to showcase the R&D being carried out at EPFL on advanced construction techniques.