Climate Future Lab

Microclimate in urban areas

There is a strong link between climate change and ongoing urbanisation. For example, 75% of people in Germany already live in urban areas and this figure is expected to rise further (Steuri et al., 2018). Through the concentration of people, economic output and infrastructure, urban centres are responsible for a large proportion of energy and resource consumption and thus for emissions of CO₂ and other greenhouse gases. At the same time, these areas in particular have great potential for tackling the climate crisis. For example, per-capita CO₂ consumption is lower in urban areas and infrastructure can be planned more cost-effectively (Wagner, 2021).

However, densely populated areas are also highly vulnerable to and severely affected by the impact of climate change. Forecasts indicate that the frequency, duration and severity of extreme weather events will increase (IPCC, 2021). This will manifest itself in floods triggered by extreme rainfall, heat waves and (especially in conjunction with excessive traffic and lack of vegetation) persistent periods of poor air quality. In urban areas in particular, these climate-related changes may have an extreme impact on people, the environment, economic activity, mobility and infrastructure as well as energy and water supplies.

The aim of this Climate Future Labs 2025 call for proposals for support is to research the impact of climate change in urban areas, with the involvement of cities, municipal authorities and citizens, and to develop approaches that promote climate protection and adaptation. In the context of the call for proposals, the term “urban areas” is taken to mean “[…] settlement structures with appropriate compactness and density in urban and rural areas” (New Leipzig Charter, 2020, p. 11).

A variety of disciplines, such as geography, sociology, building physics, biology and much more as well as interdisciplinary approaches, are explicitly invited to participate. Individual or combined focus areas may be taken into consideration. The following list is intended to prompt ideas:

• Impact of the microclimate on urban populations and their health: A potential focus could be analysis of the connections between local atmospheric conditions and health indicators in urban areas aimed at deriving preventive measures for reducing health risks, e.g. posed by heat events. Under the One Health approach, health is not limited to people.
• Biodiversity in urban microclimates and its significance for the ecosystem: Biodiversity plays an important role in ecosystem resilience in urban microclimates as well, which could be examined by analysing the environmental and climatic functions of green spaces and biotopes with respect to microclimate regulation and biodiversity conservation.
• Development of adaptation strategies and measures for improving the microclimate: The aim would be to develop an evaluation matrix for evaluating and prioritising measures based on the most important model parameters (surfaces on a building scale, radiation, vegetation, water surfaces, wind, etc.) for thermal comfort as well as the water balance, translate this into a climate model and validate the model in application scenarios, e.g. by recommending and evaluating suitable protection strategies for heat islands and flood scenarios with the involvement of cities, municipal authorities and the population.
• Interaction between social structures and microclimate conditions in urban areas: There is little information about the influence and impact of social participation processes on the quality of adaptation measures and the actual representation of the interests of marginalised groups also. The aim could be to use specific participation and communication processes in the area of microclimate to research modes of action (also in relation to democratic education) and derive concrete courses of action for spatial planning processes.
• Microclimate modelling and simulation: Microclimate modelling and simulation: This aspect builds on the current state of the art through national and European projects and addresses the extension of a numerical prediction model using a large-eddy approach to predict thermal comfort in built-up areas based on the interaction of thermal radiation with infrastructure surfaces, thermally induced flow, humidity and wind (by coupling to a mesoscale climate model such as WRF). The coupled model must be capable of being run on multi-GPGPU architectures in order to achieve practice-based computing times at spatial resolutions up to the metre scale. The validation of the simulations of specific scenarios should be realised by collecting or using suitable data (e.g. based on sensor networks, satellites, drones, etc.).
• Collecting microclimate data: The aim could be to specify simulation scenarios and validate simulations by collecting suitable data, e.g. based on sensor networks, satellites, drones, etc., as well as transfer these to suitable models.
• Development of bioclimatic approaches in the area of spatial planning and building design: This would involve examining possibilities for urban spatial planning, such as support for ventilation corridors and façade greening, the integration of green areas and roofs as well as water features, and passive solar usage or energy efficiency. Other aspects could include optimising the indoor climate in buildings and conserving resources in the interest of climate protection (for example, renovating older buildings vs. constructing new ones).
• Examination of the role of green areas and water features in regulating urban microclimate temperatures: The aim would be to research green areas and water features from the point of view of regulating temperatures, reducing heat stress, improving air quality and protecting against floods. Preferably, the findings would be integrated into a model for implementation in a sponge city with a high proportion of green spaces.