The sub‑project “Impact Mitigation Regulation and Climate‑Change‑Related Requirements” of the KommKlima consortium addressed how uncertainties arising from climate change affect the compensation mechanisms required by the German Nature Conservation Act and the German Planning Act. The research aimed to identify these uncertainties, develop adaptation strategies, and propose financing options that remain robust under future climate scenarios. The final report presents a set of methodological tools, spatial analyses, and practical recommendations for planners and decision makers.
Central to the technical outcome was the development of GIS‑based models that quantify climate‑change impacts on biotopes. These models were applied to the city of Bremen, revealing spatial hotspots where climate‑driven pressures on biodiversity are greatest. The analysis enabled the prioritisation of areas for intervention and compensation. In parallel, the team formulated three distinct financing strategies—preventive, adaptive, and post‑implementation—each accompanied by an economic cost model. The cost model demonstrated that the relative economic advantage of a strategy depends strongly on the specific cost components of a given case; no single strategy emerged as universally cheaper. This finding underscores the need for case‑by‑case evaluation of financing options.
The project also produced a set of recommendations for the practical application of impact mitigation regulation. First, compensation planning should explicitly incorporate measures that enhance landscape resilience, such as multifunctional land uses, integration into biotope networks, and soil and water‑conserving practices. Second, climate‑scenario information should be made available at the landscape‑planning level, with sensitivity analyses and suggested compensation sites highlighted. Third, when climate projections indicate a risk of degradation, the permitting authority should mandate monitoring and corrective actions. Fourth, compensation schemes that are designed to be climate‑resilient from the outset can be imposed on developers only when the specific climate risks and the effectiveness of the additional measures are clearly understood.
To gauge the acceptability of these recommendations, a stakeholder survey was conducted. The survey confirmed that practitioners value the inclusion of resilience criteria and the provision of climate‑scenario data, while also highlighting the importance of clear guidance on monitoring obligations and financing mechanisms.
The research design comprised seven work packages: literature review, development of new implementation strategies, method development for biotope impact assessment, legal clarification of climate‑related obligations, incorporation of climate uncertainties into financing, creation of new financing concepts, and stakeholder consultation. The project built on extensive prior work in impact mitigation regulation, including the development of a handbook used in Bremen and a national comparison study funded by the Federal Ministry of Education and Research (BMBF). Additional methodological contributions were drawn from studies on greenhouse gases, biodiversity, and water requirements for biodiversity.
The project was carried out by the Institute of Environmental Planning at Leibniz University Hanover, with key contributors Tim Wenzel and Christina von Haaren. The consortium also included researchers Antonia Langguth, Jara Niebuhr, Luise Pahlow, Anna‑Lea Welz, and graduate student Anna‑Lena Vollheyde, whose master’s thesis contributed significantly to the work. Funding was provided by the BMBF under reference 16LC1324B. The project concluded on 31 December 2022, following a two‑year research period that produced a four‑page short report and a ten‑page in‑depth presentation. The findings are intended to inform both national policy and local planning practice, ensuring that compensation measures remain effective and financially viable in the face of ongoing climate change.