By Susanne Togeby AAU Communications og Public Affairs
Photo: Colourbox/Privat

“Hot town, summer in the city” goes the line from a 1960s hit about the unbearable heat in the big city, where people walk the sidewalks “lookin’ half dead, hotter than a match head.” The heat hasn’t lessened since then—quite the opposite! Temperatures are rising due to climate change. Summers in Europe are getting hotter, and the growing number of heatwaves poses a health risk to both people and animals.

Two students, Rikke Selvig Andersen and Josefine Brejnbjerg Buch, have studied how different urban surfaces can either increase or reduce temperatures. Specifically, they analyzed data from Copenhagen.

“We found that blue spaces such as lakes, streams, or the sea can help cool down the city. The effect depends on the type of water present. The sea, in particular, has a strong cooling effect. And when blue areas are combined with green spaces full of plants and trees, the cooling effect becomes even stronger,” says Rikke Selvig Andersen.

We Need to Preserve Green and Blue Spaces in Cities

The students reached their conclusions by combining satellite data, geographic information systems (GIS), and statistical analysis. Their research shows that the interaction between water and vegetation plays a key role in keeping cities cooler. In contrast, asphalt and concrete—common features of urban landscapes—prevent the ground from absorbing and distributing heat, which contributes to higher temperatures, the two students explain.

This knowledge makes it possible to design cities that are better equipped to handle heat and reduce its negative impacts on public health, energy consumption, and the environment.

“We’ve demonstrated the importance of preserving both green and blue spaces in cities— also in combination,” says Josefine Brejnbjerg Buch. “We hope our findings can inspire future urban planning, using this knowledge of which areas have the greatest effect on temperature.”

Translated by Emma Holtegaard Hansen