Hamburg, Germany
City population: 1698688
Duration: 2015 – 2019
Implementation status: Completed
Scale: Meso-scale: Regional, metropolitan and urban level, Sub-microscale: Street scale (including buildings)
Project area: 1000000 m2
Type of area: Building
Last updated: November 2021

Due to the challenges caused by climate change, Hamburg decided to become greener and developed a comprehensive, pioneering green roof strategy. The strategy aims at creating 100 hectares of new green walls by 2019 by providing grants for building owners for greening roofs and offering them rain water fee reduction owing to the rain water retention of the green roofs. (Reference 1) The financial support offered until the end of 2019 is 3 million EUR. (Reference 2) The services offered by the city in this plan consist of four pillars: promotion (financial incentive), dialogue, regulation, and scientific support. (Reference 7)

Green roofs aerial photo


Nature-based solution

  • Nature on buildings
  • Green roofs
  • Parks and urban forests
  • Pocket parks/neighbourhood green spaces
  • Green areas for water management
  • Sustainable urban drainage systems

Key challenges

  • Climate action for adaptation, resilience and mitigation (SDG 13)
  • Climate change adaptation
  • Water management (SDG 6)
  • Flood protection
  • Stormwater and rainfall management and storage
  • Green space, habitats and biodiversity (SDG 15)
  • Habitat and biodiversity conservation
  • Green space creation and/or management
  • Environmental quality
  • Air quality improvement
  • Regeneration, land-use and urban development
  • Regulation of built environment
  • Promotion of naturalistic urban landscape design
  • Health and well-being (SDG 3)
  • Enabling physical activity
  • Creation of opportunities for relaxation and recreation
  • Economic development and employment (SDG 8)
  • Real estate development


Creation of new green areas, Knowledge creation and awareness raising, Strategy, plan or policy development

Project objectives

- improving the quality of open green city spaces - encouraging space efficient leisure areas - improving the city’s rainwater retention capacity - increasing biodiversity - improving the city climate (reduction of the heat island effect) - improving the liveability of the rapidly growing city (Reference 2, 3 and 7)

Implementation activities

For fulfilling the ambitions of the Green Roof Strategy, the city combines promotion, dialogue, regulation and scientific support: - Promotion: providing subsidies for building owners (private and public) for installing green roofs voluntarily as refurbishment or as an element of a new building. Citizens or companies can apply for the funds if they voluntarily plan to install at least 20 sqm of green roofing with a soil layer of at least 8 cm in depth. (Reference 8) - Communication and dialogue: organizing an awareness raising campaign (“On Your Roofs, Get Set, Green!”), starting a dialogue with local politicians, authorities, architects, engineers and economists on the topic. - Regulation: incorporating or enhancing the strategy into legally binding instruments like the Hamburg Building law, the wastewater law, planting regulations on structural systems and land-use plans - Scientific support: HafenCity University supports the program by evaluating international findings on green roofs, developing recommendations for Hamburg’s green roof construction, and collecting data on water retention and the water management effectiveness of green roofs. As part of the project, the city of Hamburg published a comprehensive guide about how and why to implement green roofs. (Reference 1, 2)

Climate-focused activities

Climate change adaptation:

  • Increase or improve urban vegetation cover to help reduce outdoor temperature
  • Create or improve outdoor spaces to help people escape from urban heat
  • Implement green walls or roofs to lower indoor temperature and provide insulation

Biodiversity conservation or restoration-focused activities

Biodiversity conservation:

  • Protect and enhance urban habitats
  • Preserve and strengthen existing habitats and ecosystems
  • Promote environmentally-sound development in and around protected areas
  • Create new habitats

Main beneficiaries

  • National-level government
  • Local government/Municipality
  • Private sector/Corporate/Company
  • Researchers/University
  • Citizens or community groups


Management set-up

  • Co-governance with government and non-government actors

Type of initiating organisation

  • Local government/municipality

Participatory approaches/ community involvement

  • Dissemination of information and education
  • Joint implementation (e.g. tree planting)

Details on the roles of the organisations involved in the project

"The Hamburg Ministry for Environment and Energy is providing financial support for the creation of green roofs to the sum of € 3 million until the end of 2019 [...] Within the city a stakeholder group was established including housing estate companies, constructors, landscape architects and urban planners. Parallel to the dialogue with other cities this group was involved in defining the incentive programme. The group has remained active since and during its bi-annual meetings the Green Roof Strategy is evaluated by the working group" (Reference 2). Hamburg is the first German city that has developed a comprehensive green roof strategy. Furthermore, the German Federal Ministry for the Environment, Nature, Building and Reactor Safety supports the strategy as a pilot project within their programme “Measures for adaptation to climate change” (Reference 2).

Project implemented in response to ...

... an EU policy or strategy? Unknown
... a national policy or strategy? Yes (The description of the project writes: "The current Green Roof Strategy combines the urban development policy objectives of sustainable area development with the objectives of adaptation to global warming and climate change [...] in accordance with the Nature Conservation Act green roofs are considered a possible measure in the context of compensating building impact on nature" (Reference 2).)
... a local policy or strategy? Yes (The description of the project writes: "The current Green Roof Strategy combines the urban development policy objectives of sustainable area development with the objectives of adaptation to global warming and climate change. In Hamburg binding green roof regulation has been incorporated in many land-use plans for 20 years. Also, in accordance with the Nature Conservation Act green roofs are considered a possible measure in the context of compensating building impact on nature. From 2020 onwards Hamburg plans to have green roofs to be compulsory by law. The city of Hamburg also regularly reviews its green roof legislation in particular with regards to the ecological quality standards for the roofs. Specifically, when updating Hamburg’s regulations next time, the aim is to increase the standard green roof thickness up to 12-15 cm" (Reference 2).)


Total cost

€2,000,000 - €4,000,000

Source(s) of funding

  • Public regional budget
  • Public local authority budget

Type of funding

  • Direct funding or subsidy
  • Tax exemption

Non-financial contribution


Impacts and Monitoring

Environmental impacts

  • Climate, energy and emissions
  • Lowered local temperature
  • Strengthened capacity to address climate hazards/natural disasters
  • Reduced emissions
  • Generation of renewable energy/Energy efficiency improvements
  • Environmental quality
  • Improved air quality
  • Improved protection against strong wind
  • Water management and blue areas
  • Increased protection against flooding
  • Improved stormwater management
  • Green space and habitat
  • Promotion of naturalistic styles of landscape design for urban development
  • Increased green space area
  • Increased conservation or restoration of ecosystems
  • Reduced biodiversity loss
  • Increased number of species present
  • Other

Economic impacts

  • Reduce financial cost for urban management

Socio-cultural impacts

  • Social justice and cohesion
  • Improved liveability
  • Improved access to urban green space
  • Increased opportunities for social interaction
  • Health and wellbeing
  • Improved physical health
  • Gain in activities for recreation and exercise
  • Other

Type of reported impacts

Achieved impacts

Presence of formal monitoring system


Presence of indicators used in reporting


Presence of monitoring/ evaluation reports

No evidence in public records

Availability of a web-based monitoring tool

No evidence in public records


Green Bunker