Biodiversity offsetting through expropriation? Comparing the cases of Germany and Norway

Abstract Biodiversity offsetting requires access to land beyond development sites. This raises legal questions about how such land can be secured where voluntary acquisition is not possible. This article examines whether German and Norwegian law provide a statutory basis for expropriation to secure land for biodiversity offset measures and under what legal conditions such expropriation may occur. Biodiversity offsetting occupies a hybrid position between development and environmental law, blurring traditional categories of expropriation law. The comparative analysis demonstrates that expropriation for offset measures does not constitute an autonomous expropriation purpose but instead derives from statutory frameworks authorising development projects, rather than from an explicit statutory basis. Although the two systems share structurally similar expropriation frameworks, they diverge in their interpretation of the necessity requirement. In Germany, ‘legal necessity’ arising from binding offset obligations suffices to support ancillary expropriation for offsets. Development projects may in fact be implemented without offsets, but obligations under environmental law render offset measures necessary for lawful project implementation. In Norway, necessity is limited to factual and technical indispensability, thereby excluding offset measures from ancillary expropriation. German case law confirms that biodiversity offsetting may, under strict conditions, satisfy the proportionality requirements of constitutional and conventional property protection. However, its derivative character raises concerns regarding the clarity and accessibility of the statutory basis for expropriation. This helps explain why expropriation for offset measures occurs rarely and remains legally uncertain. An explicit statutory basis may be required to ensure both the legitimacy and effectiveness of expropriation amid increasingly ambitious no net loss and restoration commitments.