The Free and Hanseatic City of Hamburg has a diverse population of about 1.9 million people and ranks among the richest and economically strongest regions in Europe. It is located close to the North and Baltic Sea and sits at the confluence of the River Elbe and two of its tributaries, the Alster and the Bille. The Port of Hamburg, known as “Germany’s Gateway to the World,” is the third largest in Europe.
Climate challenges the city is facing:
Hamburg is characterized by a maritime climate due to its proximity to the North Sea. The city faces several climate challenges driven by rising temperatures, varying seasonal precipitation, and extreme rainfall events.
The city has warmed by approximately 1 °C since 1961–1990 and nearly 1.7 °C since the 1880s. Hot days, tropical nights, and prolonged heatwaves, like the record-breaking event of 11 days measuring above 30 °C in August 2020, are expected to become more frequent. The urban heat island effect amplifies this, with nighttime city temperatures up to 2.7 °C higher than surrounding areas, posing risks to public health.
Annual precipitation averages around 720 mm but varies strongly throughout the year, with summer being the wettest season. Hamburg has experienced extended dry periods in recent years (e.g., 2018, 2020), as well as intense rainfall events. Climate change is projected to increase the risk of heavy downpours and localized flooding, while longer dry spells may also occur.
Hamburg’s location along the Elbe and near the North Sea makes it highly vulnerable to storm surges, riverine flooding, and pluvial flooding from heavy rainfall. Impervious urban surfaces further exacerbate flood risks. In the long term, rising sea levels could impact Hamburg through groundwater flooding.
Adaptation strategies and policies:
Historically, floods and storm surges have been at the centre of Hamburg’s disaster risk reduction efforts. Initially, climate change adaptation in Hamburg mostly focused on these water-related hazards, but increasingly broadened to include other hazards too. At the city level, the 2015 Climate Plan was central to Hamburg’s adaptation efforts.
However, climate adaptation was excluded from the plan’s second update in 2023. Instead, a dedicated adaptation strategy— along with a heat action plan —was introduced in 2025. Alongside these city-wide initiatives, Hamburg’s districts have also begun developing their own local adaptation strategies, further advancing climate resilience across the city. In addition, the public and private sectors, civil society, and other actors engage in adaptation efforts.
Notable I4C-related projects and actions:
CoSynHealth: Conflicts and Synergies between Carbon-Neutral and Healthy City Scenarios
The CoSynHealth project, led by GERICS and partners, explores how carbon-neutral urban development can align with public health and climate adaptation goals. Using high-resolution climate and agent-based modelling in Hamburg-Altona, it assesses how mitigation measures (e.g., low-carbon lifestyles) affect heat stress and health outcomes at the neighbourhood level. The project engages stakeholders in participatory processes to develop climate services that highlight trade-offs and enhance synergies between carbon neutrality, resilience, and health.
HaLaGa: Strengthening Agriculture and Horticulture against Climate Change
The HaLaGa project supports Hamburg’s ~600 agricultural and horticultural enterprises in adapting to growing climate risks such as extreme weather and production losses. The initiative, led by GERICS with the Hamburg Chamber of Agriculture, develops farm-specific climate risk analyses and tailored adaptation strategies through close cooperation with six pilot farms. Activities include creating a practical farm check tool for climate resilience, delivering customized climate information, and identifying policy options to improve framework conditions for adaptation.
SYnAPTIC: System dynamics for resilient critical infrastructure
The SYnAPTIC project applied a system dynamics approach in the Hamburg metropolitan region to assess how climate change impacts (e.g., droughts, floods, heatwaves) affect critical infrastructure sectors such as energy, water, and transport and their interdependencies. Through stakeholder mapping, expert interviews and participatory workshops, the project identified key vulnerabilities such as the dependence of water supply on electricity grid stability and the cascading risks triggered by extreme events. The findings highlight the need for long-term investment, cross-sectoral collaboration, and resilient infrastructure planning.
Stakeholder and community engagement:
Involvement of citizens, businesses, and other stakeholders in adaptation planning varies depending on the level of decision-making and issue at hand. For example, the heat action plan of 2025 was developed through consultations with all departments of the city administrations and the districts, as well as through participatory stakeholder workshops with more than 100 representatives from the civil society, research, private, and public sector.
Contact / Further Information:
- To learn more about Hamburg’s climate change adaptation strategy (in German).
- To visit Hamburg’s climate information system on climate trends, impacts, urban development and more (in German).
- The “Klimareport Hamburg” of the German Weather Service (DWD) summarises the city’s climate of the past, present and future (in German).
- To learn more about the Climate Service Center Germany (GERICS).