Dormagen/Düren (German federal state of North Rhine-Westphalia), August 29, 2024. Records are usually a cause for celebration – but not when it comes to climate change. In June, southern Germany was submerged in once-in-a-century flooding. In July, the Copernicus Climate Change Service reported Earth’s hottest day since records began in 1940.[1] In the face of climate change, these records are likely to be broken before long. The towns, cities and municipalities worst affected by the extreme weather are those not structurally designed to withstand such weather events. Germany’s new Federal Climate Adaptation Act (Klimaanpassungsgesetz – KAnG) is aimed at changing this, and requires federal states and municipalities to develop appropriate strategies. In the federal state of North-Rhine Westphalia, the city of Dormagen and the administrative district of Düren provide examples of how a climate adaptation pathway can look. They are working with Drees & Sommer SE, a consulting firm specializing in construction and infrastructure, to identify measures to prepare better for weather extremes.
Janis Hackbarth, who has been working as climate adaptation manager for the city of Dormagen for over a year, commented: “We want to ensure Dormagen is prepared for climate change“. Almost fifteen years ago the city, along with local nature conservation associations, launched a climate action plan which advocated, among other things, renewable energies and the expansion of the public transport system. However, as Janis Hackbarth explained, Dormagen now wants to go a step further: “We are currently analyzing precisely what measures will best help us to adapt to climate change and protect us against heat, heavy rainfall and flooding.”
Protection against floods and heavy rainfall
For Tanja Sprenger, Drees & Sommer’s climate change adaption consultant who provides advice to the city administration, the first step in every action plan is an impact analysis: “The first thing is always a stocktake of local climate changes and their consequences. Dormagen covers an area of 85 square kilometers and is bounded to the north and east by the river Rhine.
Several streams also meander through the city. This means that in extreme cases large areas of the city can be affected by flooding.”
There are already mobile flood control systems in place to protect the city from flooding from the river Rhine. However, on their own they do not provide sufficient protection against a future heavy rainfall event. The city administration therefore wants to create more infiltration areas to absorb excess water when there is a downpour. Tanja Sprenger pointed out: “Not all squares and paths have to be surfaced with asphalt. Stone chippings like you find in beer gardens and grass pavers in parking lots also work.” What Janis Hackbarth is mainly referring to here are the city’s school yards and squares: “Far too many of these areas are paved. We want to take urgent action against this and introduce more planting – which would also improve the livability of the city” Green roofs and façades, and climate-adapted planting are also of major importance, according to Janis Hackbarth. In addition to allowing water to soak into the ground, the additional green spaces have a further positive effect: on hot days they provide shade and create an evaporative cooling effect as well as improving air quality.
The City Center as Urban Heat Hot Spot
The large amount of surface sealing with concrete, asphalt and glass that is currently the practice results in a phenomenon known as the urban heat island effect in summer months. Tanja Sprenger said: “In urban areas, this can result in temperatures up to 10 degrees higher than the surrounding areas. By creating shade, particularly with correct planting, cities can dramatically improve their microclimate.“ However, as Tanja Sprenger added, it takes some time for trees to develop to their full potential, so tree planting has to be combined with other, fast and cost-effective measures. This is why Dormagen has installed its first free drinking fountains in the busiest squares and in the pedestrian zone, with the aim of encouraging people to drink often and helping to protect them against heat-related illnesses. The city is also investigating how digital tools can help with climate adaptation, for instance sensor technology or apps, which people could use to mark where the urban heat hot spots are to be found.
However, the city’s administration does not bear sole responsibility for successful climate adaptation. Many properties are privately owned, which is why Tanja Sprenger says it is important to involve the public: “Owners can protect themselves better by planting and creating shade. There are also affordable measures to protect existing building structures from flooding in emergency situations. Proven solutions include installing pumps and non-return valves, raising light wells, and installing cellar doors and windows that withstand water pressure.“ To achieve results as quickly as possible, Dormagen’s administrative authority provides subsidies to private individuals who plant climate-resilient trees in their gardens. As Tanja Sprenger remarked, climate adaptation is a challenge for the whole of society and requires everyone’s cooperation.
District of Düren: Forests for Climate Mitigation instead of Coal Opencast Mining
Another person attending to this issue is Moritz Gebauer. He is one of three climate adaptation managers for the administrative district of Düren. Their joint task is to develop a tailored plan for fifteen towns and municipalities. Moritz Gebauer stressed the role of public participation: “Our goal is to create awareness of climate change. We organize events and workshops in order to sensibilize people for this topic and also to generate ideas.“ The district faces particularly big challenges. Some parts of it are situated in the Rhenish mining region, the largest continuous lignite mining area in Europe. Here, surface mining has left deep scars. Tanja Sprenger explained: “Everywhere that coal was mined, villages and nature have been disfigured by barren spoil heaps. Groundwater depletion and destruction of habitats are defining characteristics of these areas.
There are huge opportunities associated with gradually filling the surface mines with water and returning these huge areas to the public and to nature.“
Structural change could therefore provide an opportunity to renature the region. In the climate adaptation plan for Düren it became clear how hard the municipalities on the margins of the coal opencast mining sites are hit by dust-laden winds from the direction of the surface mine, localized storms, and heat and drought events. The creation of new bodies of water and green areas, as well as the removal of impervious surfaces, creates new habitats for animals and plants here too, while at the same time mitigating the impacts of extreme weather events. Tangible initiatives are already in place: forests for climate mitigation are to be created in the municipalities of Inden and Altdorf in and around the former opencast mining sites, which will be adapted to future climate conditions. The goal is to plant the entire district area with a total of 300,000 drought-tolerant trees. As the district administrator of Düren, Wolfgang Spelthahn, pointed out: “The best climate adaptation is effective climate change mitigation. We have to take a preemptive and proactive approach instead of only acting when something happens and it is too late. We aim to consider this in our climate adaption plan and guard against negative consequences.“
Local Solutions for Global Problems
The district of Düren and the city of Dormagen are continuing to work at full stretch on their climate adaptation plans. The details should be worked out in the coming year, and the plans could then serve as a guide for other municipalities, as Tanja Sprenger explained: “The relevant measures will differ according to the local conditions. However, there is also empirical data which can be applied to all plans. Early involvement of citizens, the administration, the emergency services and others is very important for joint clarification and definition of possible actions. Private individuals, companies and public bodies must also work together, for instance to site new housing developments in a way that allows for the planning of sufficient green and infiltration areas. For existing buildings, it can help to attach green façades or to lighten sealed surfaces in order to avoid absorption of solar radiation.“
Climate adaptation comes at a price: Agora Energiewende, a think tank supporting the energy transition in Germany, estimates the investment required from the German federal government, federal states and municipalities at around 260 billion euros, plus a further 200 billion euros for incentive systems.[2] Despite the huge amount of capital required, taking a wait-and-see approach is not an option, according to Tanja Sprenger: “Recent calculations by the German Federal Ministry for Economic Affairs and Climate Action suggest that by 2050 the future cost of climate change will be between 300 and 900 billion euros– depending on how quickly it advances. On top of this are the consequences that cannot be measured in monetary terms. Health impacts, including heat-related deaths, pressure on ecosystems, and the loss of biodiversity are also part of the cost. All of this has to be taken into account in a climate adaptation plan for sustainable urban and spatial development.“
[1]Climate Pulse (copernicus.eu)
[2]https://www.agora-energiewende.de/publikationen/oeffentliche-finanzbedarfe-fuer-klimainvestitionen-im-zeitraum-2021-2030 in German (Public financing requirement for climate investments in the period 2021-2030)