The urban race against climate change: greening one of Germany’s hottest cities

This kind of cooling is needed urgently in cities around the world – but especially Stuttgart. The vibrant capital of Baden-Württemberg in southwest Germany, Stuttgart is best known for strong industrial roots, and as the home of iconic automotive brands Mercedes-Benz and Porsche. Perhaps fittingly, it is also forecast to become one of Germany's hottest cities, with the number of heat stress days projected to double by 2050 while winters will be up to 50% wetter. 

Why so hot? 

Rainer Kapp, the city of Stuttgart’s Head of Urban Climatology, explains that the city centre is in a valley with minimal wind. Combined with dense urban development, the result is a “pronounced heat island effect, meaning much warmer nights compared to the surrounding area.” Plus, he adds, “the valley basin location and the heavy sealing make Stuttgart susceptible to flooding in the event of heavy rainfall events.”

Action is needed to prevent the worst effects of rising temperatures in Stuttgart. Heat is already harming people and wildlife in the city. “Heat has a stressful effect on people, especially for the heart and circulation. Overall, the number of heat-related hospital admissions is increasing,” Kapp says. “Trees and plants also suffer from heat and drought stress – certain species will not be able to survive in the future.” 

Lowering the temperature

Stuttgart’s authorities have already stepped into action. The municipality first appointed a meteorologist to study climate conditions in the city back in 1938 when the science of urban meteorology was in its infancy. Fast forward to the 21st century, and the city’s 2012 climate adaptation plan (KLIMAKS) set out a roadmap for tackling climate change. Today, Kapp leads a cross-departmental group that renewed this action plan in 2024 to contain more than 70 individual measures for climate adaptation.

The city is also aiming to achieve net zero by 2035. Progress is being powered, in part, by the Climate Innovation Fund – the largest municipal innovation fund for the climate in Europe. Stuttgart launched the fund in 2021 to support innovative climate solutions from science, business and civil society. The Nature Conservancy (TNC) joined forces with the fund a year later, and has supported Stuttgart’s climate adaptation efforts thanks to funding from Amazon’s Right Now Climate Fund for TNC’s Urban Greening Program in Europe. Together, TNC and the Climate Innovation Fund created the Ivy line: a dedicated funding line to bring more urban greening solutions to Stuttgart’s streets.

So far, the Ivy programme has supported 19 urban greening projects with activities across 30 different neighbourhoods. Each one is created and run by organisations – universities, startups, NGOs – who are connected with Stuttgart’s local neighbourhoods and selected by a panel of experts to receive funding.

Greening in action

Projects have taken many shapes and sizes. ”It’s amazing to see how creative people get,” says Sophie Mok, an urban greening expert at TNC who is embedded in the Climate Innovation Fund’s team. In one part of the city, the Car2tree project has transformed car parking spaces – which have been freed up by declining car ownership in Stuttgart – into mini roadside parks with plants and wooden seating. Cleverly designed benches in schools and daycare centres will offer a comfortable seat while collecting rainwater that is used to irrigate nearby green spaces. Across three sites around the city, 800 native trees and shrubs are soon to be planted in so-called ‘tiny forests’ that support biodiversity and lock away 40 times more CO2 than a conventional forest.

Doing urban greening well involves not only plants and wildlife but people. The Ivy programme’s projects – and others across the city – take the community as their starting point. Jamie Chan is The Nature Conservancy’s director of Urban Greening across Europe, and works across multiple cities to bring nature into urban spaces. “When you have an idea to transform an urban space, the people who use that space need to be involved from the onset, and be part of the conversation,” she says. In particular, green urban areas should be accessible to people in underprivileged areas. 

A central challenge of any urban greening work is that space in cities is at a premium. Every square metre is contested, with competing needs and priorities for different people and initiatives. Trees can frustrate business owners by obscuring store fronts, for example, and car owners may prefer having space for wide roads and parking. Successful urban greening projects must navigate this sensitively and proactively.

The Car2tree project, for example, has open hours where local people can drop in and ask questions, and the project team attend local neighbourhood events where they can interact with residents. “It’s about telling people stories about the benefits in a way they can relate to, but also hearing their fears so they can address them in the project design”, Mok says. These kinds of conversations build the widespread support needed for a project to keep going, so its impact can last well into the future.

Success in urban greening, then, is as much about people as it is about nature. Networking events connecting the passionate people behind many of Stuttgart’s urban greening projects and other climate innovators have proven popular, and now run twice a year. The Ivy programme has now actively involved more than 1000 citizens and stakeholders.

Urban greening can connect people not only with each other, but with the natural world. As Mok says, it is a powerful reminder that “people belong to nature”. Turning grey cities green again is an opportunity to show that there can be “better living in the city,” she adds. It is through urban greening that cities can – and must – adapt to a changing climate, and become vibrant ecosystems where people, animals and plants can thrive together.