Adapting from the Ground Up: Climate-Resilient Construction in Herne, Germany

Key Learnings

About the Region

Figure 1: City of Herne's location. Image Credit: Wikipedia images.

Climate Threats

Over the past few decades, Herne, as part of North Rhine-Westphalia, has experienced a notable rise in average temperatures, with a growing number of hot days (above 30°C) and tropical nights (above 20°C). Projections suggest that average temperatures could rise by up to 2.3 °C by 2050 under high-emission scenarios (LANUV report 157; Klimaatlas NRW). Herne is particularly vulnerable to heatwaves due to its dense urban structure, which intensifies the urban heat island effect, resulting in higher temperatures within the city compared to its surroundings. The city also faces increasing risks of flooding and heavy rainfall, as seen in the devastating floods across North Rhine-Westphalia in 2021, causing 49 fatalities in the federal state. Droughts and declining groundwater levels have also become more frequent, contributing to ecological stress and water scarcity.

Climate-proofing private building works increases resilience

Herne’s Climate Adaptation Plan essentially serves as a procedural model for evaluating planning projects, with the overall aim of incorporating climate adaptation into community planning practices early on, rather than viewing it as a nice-to-have or sideline approach. The city of Herne requires the integration of adaptation into planning processes within the city area, making the Climate Adaptation Plan a legally binding instrument.

Before approving a specific building location, the city council must first verify internally whether the targeted area has any identified tensions between people using the Climate Adaptation Map. If this is the case, the process requires clarifying the type of conflict potential involved. For example, these include heat stress, reducing the ventilation or cooling function of an area, or increasing the flood risk. Then, the council determines the appropriate adaptation measures, as outlined in the Climate Adaptation Catalogue (in German, p. 52).

Mainstreaming climate change into spatial planning

The implementation of climate adaptation measures is particularly necessary in urban planning, as this offers the opportunity to make urban areas resilient to climate impacts as early as possible. Key areas of action include adapting settlements, open spaces, and infrastructure.

The major challenge for the coming years is not only to have climate adaptation plans readily available alongside everyday municipal planning, but also to integrate them into municipal planning processes. In this way, they will not remain mere well-intentioned recommendations for action and helpful guides, but will become established and, above all, binding components of municipal planning for the stakeholders involved. Figure 2 illustrates the process that guides the integration of climate adaptation into city planning in Herne. This internally developed framework is mandatory and has proven to be a valuable tool for supporting decision-making and ensuring consistency.

Figure 2: Integrated Planning Process Herne. Image Credit: The city of Herne.

There are four steps for applying  the assessment grid with the Herne checklists for the Climate Adaptation Plan, which applies to all planning processes and relevant urban development projects:

Step 1: Area Assessment to Prioritise Need for Action

• First, the location of the affected area within Herne must be reviewed. Potential exposure to heat and/or flooding during extreme rainfall events must be considered in subsequent steps of the planning process.
• This step examines the potential for climate conflict.
• Resources for completing Checklist 1 include the "Climate Adaptation Action Map" and the "Heavy Rainfall Hazard Map" for Herne. Additional thematic maps from the climate analysis conducted by the Ruhr Regional Association can also be utilised.

Step 2: Project Assessment to Prioritise Need for Action

• This checklist examines the type of planned project and its impacts on the climate in terms of adaptation and, indirectly, mitigation.
• Resources for completing Checklist 2 include the development plan, building project descriptions, or similar.

Step 3: Implementation of Measures

• For the planning project, relevant climate adaptation measures should be identified and compiled based on the specific climatic stresses. If updating an existing development plan, it must be reviewed across departments to ensure the integration of appropriate adaptation strategies.
• Depending on the type of planning, the checklists for urban structure/buildings, for development planning (Checklist 3b), or for green and open space planning must be completed.

Step 4: Assessment of the project’s "climate adaptation" scope

• The degree of planned project’s climate adaptation scope is assessed based on the final climate-proofing score.
• The planning process is presented to policymakers and the public, and undergoes different levels of public participation

Planned projects that achieve a total score of less than -6 are not sufficiently adapted to climate change. These could be corrected by implementing additional adaptation measures. If the area affected by the planned project has a significant potential for climate conflict, compensation through adaptation measures is often insufficient to achieve at least a neutral to good climate adaptation score. The result of the check is politically binding. The planning authority incorporates the measures identified through the climate check into the development plan specifications during the planning procedure and formally adopts them. Once adopted, these measures become legally binding under a statutory resolution. For example, the climate check identifies extensive green roofs and green façades as key climate adaptation measures, which are incorporated into the development plan as mandatory requirements, thereby making them legally binding.

Promoting climate adaptation among homeowners

Based on the Climate Adaptation Plan, the city council developed the “Climate-Check” for homeowners. It is an awareness-raising approach about the climate risks the city is facing and the active role every homeowner can take in adapting to those risks. To increase the city’s resilience to the effects of climate change at the local scale, particularly flooding and heatwaves, Herne decided to introduce the Climate Check, a climate-proofing form. This is intended to motivate homeowners to incorporate adaptation measures when (re-)building on their property.

Every construction activity requires a building permit issued by the city administration. Regardless of the type of work homeowners intend to carry out, each project must include climate-adaptation measures to enhance resilience and reduce long-term costs. To assess how well a project integrates these measures, the permit form includes a checklist indicating which adaptation actions the homeowner plans to implement (Table 1).

Table 1: Overview of Climate-proofing assessment.

Depending on the construction work, the Climate Adaptation Catalogue provides a set of measures that homeowners can also implement at the building level (page 103 ff.):

• Greening measures: Tree plantings, roof greening, façade greening (Figure 3)
• Materials and colours: Choosing bright materials and light colours to lower surface temperatures
• Dealing with flooding and heavy rain: rainwater reuse, structural flood prevention measures during heavy rain, where Nature-based Solutions are not possible

Figure 3: Intensive façade greening with wild vine. Image Credit: K.PLAN.

Adaptation measures should accompany any building activity that increases surface sealing – for example, the creation or enlargement of parking spaces, houses, or garages. Sealed surfaces absorb and store heat more quickly than green areas, a difference that becomes especially pronounced during hot summer days. This leads to higher local temperatures around private homes, reducing comfort and well-being and increasing health risks. Prolonged exposure to high temperatures can contribute to cardiovascular strain and poses a serious threat to human health.

(Re-)Building activities, therefore, offer an important opportunity to integrate adaptation measures at an early stage. Homeowners or architects can complete the climate-proofing form during the planning phase, ensuring that suitable measures are incorporated from the outset. The completed form is submitted together with the building permit application and reviewed by the city council.

Surface sealing or land use generally reduces a project’s score by one point. Any construction project that occupies land must therefore include climate adaptation measures. Each measure adds one point, meaning that a single well-chosen measure can fully compensate for the negative impact of sealing. The final assessment of the project is based on its total score, as shown in Table 1.

The municipal administration and city council have increased awareness of climate adaptation and intensified their engagement in a constructive dialogue concerning climate adaptation measures.

The awareness of the need for climate adaptation has been implemented through the climate checks.

City of Herne

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