Global Green-Gray Community of Practice



A hybrid green-gray approach to infrastructure — one that combines “green” ecosystem conservation and restoration with “gray” conventional engineering — can generate more benefits and climate resilience for people and nature than either strategy applied alone.



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Our challenge

Green-gray infrastructure innovations are emerging, and not yet in common-use by engineers and practitioners globally. The faster we innovate, pilot, learn, and reach scale with green-gray techniques, the faster we can minimize, avoid, and even reverse continued biodiversity loss and climate breakdown.


Our solutions

The Global Green-Gray Community of Practice, created in 2020, is an international group working to:

Innovate and pilot new green-gray approaches
Expand science, engineering, and policy activity
Increase awareness of green-gray infrastructure’s applications across geographies and settings
Build a community to increase broad acceptance and use of these ideas and enable access to finance

Coastal green-gray cost-benefit analysis tool

Conservation International developed a coastal Green-Gray Cost-Benefit Analysis (CBA) Tool to illuminate the business case for green-gray infrastructure and address key knowledge and data gaps that inhibit widespread adoption of these solutions, with initial focus on Mexico, Brazil, Guyana and Suriname.

Quantifying the co-benefits of green-gray infrastructure is essential for making the business case needed to catalyze investment into natural infrastructure solutions globally. The CBA Tool places the scientific and technical information about the costs and benefits of coastal nature-based infrastructure into the hands of project sponsors, designers, and engineers. The tool accounts for the multiple benefits that ecosystems provide and analyzes different types of coastal infrastructure using a triple bottom line approach to quantify the social, environmental, and economic costs and benefits of infrastructure investments.

It enables the user to compare green, green-gray or gray infrastructure alternatives — whether the project is at the conceptual stage or further along with detailed data available.

Download CBA Tool (3.7MB) Download User Guidance (1.7MB)


Green-gray infrastructure playbook

The fight for increased climate resilience, restored biodiversity and sustainable economic growth is one that humanity cannot lose. Green-gray infrastructure has a vital role to play, by channeling a key driver of economic growth — namely infrastructure — to chart a more sustainable, climate, and nature-positive path. To do this, we need more financing for green-gray infrastructure, more projects in the pipeline, and to bring new private sector financing players into the space.

Given the urgent need and growing opportunity for green-gray infrastructure’s role in more sustainable and resilient development, The Playbook defines strategies to advance green-gray projects more quickly around the world — starting now.

As green-gray infrastructure projects demonstrate their cost-effectiveness, resilience, and diversify revenue streams, projects will gradually shift from grant and public finance to commercial finance that expect a greater focus on risk-adjusted returns. Achieving this transition will require improvements to the enabling environment, proving the case of individual projects, and gradually building project developer and investor confidence to mainstream green-gray infrastructure into the engineering and infrastructure finance world.

The Playbook defines the roles, responsibilities, and replicable funding and financing models required to develop green-gray infrastructure at scale — and win the game.

Download report (16MB)


New green-gray infrastructure engineering guidance

Guyana is among the countries most profoundly threatened by climate change induced sea level rise, with 90% of the population and 75% of agricultural production situated on the low-lying coastal plain. To mount a response to this existential threat, Guyana needs to harness the same natural processes that created the North Brazil Shelf’s coastal plain – a flux of Amazonian soil particles transported along the coast and captured in the roots of mangroves.

This Engineering Guidance is divided into two main outputs:

  1. Recommendations for practical Engineering Guidelines for the assessment, development and implementation of green-gray infrastructure along Guyana’s coast, including the identification of site specific green-gray interventions; and
  2. A technical resources document providing the theoretical background for the guidelines.

Download report (14MB)


Engineering guidelines for the 21st century

The current approach to evidence-based decision making for nature-based solutions is at best – project, region, or problem specific. At worst, it is non-existent or proprietary.

This paper proposes a path forward by collaborating across disciplines and geographies to design a modern data sharing platform for users to input technical knowledge and data about nature-based solutions projects. The platform would be open-access – making data and resources broadly and equitably available – while providing a real-time feedback loop from practitioners to designers, planners, and financiers.

The resulting Natural Infrastructure Engineering Hub would become a resource internationally for how to design, build, monitor, measure, maintain and adaptively manage nature-based engineering solutions.

Download report (2.5MB)


New report from the Community of Practice

The Practical Guide to Implementing Green-Gray Infrastructure is a tool for identifying, funding, planning, designing, constructing, and monitoring green-gray infrastructure projects, to increase the resilience of vulnerable cities, communities, and assets around the world.

The Guide includes 35 case studies from around the world, identifies key challenges a practitioner may seek to resolve, and where green-gray solutions can meet project goals and integrate into different land use types.

As the Community of Practice continues to build the knowledge base about how to implement green-gray infrastructure solutions, we are committed to pre-competitive collaboration to create fertile ground for innovation and new partnerships within and across sectors.

This is a living document and the Community of Practice will continue to improve and update the Guide as new information is discovered and as design techniques evolve.

Please, put this guide to use and join us!

Download report (18MB)


Interactive webinar series

Join us every month for a webinar series on Sustainable Infrastructure: Putting Principle into Practice. Click here for more information and to register for upcoming sessions.


Watch session 4 of the first round of interactive breakout sessions at the 7th EbA Knowledge Day hosted by the Green-Gray Community of Practice, CI, FEBA and AECOM: An introduction to the Practical Guide to implementing Green-Gray infrastructure and interactive dialogue on how engineers and ecologists can work together – to plan, design and build green-gray solutions.

EbA Knowledge Day Session

Watch our interactive breakout session with an introduction to the Practical Guide to implementing Green-Gray infrastructure and interactive dialogue on how engineers and ecologists can work together – to plan, design and build green-gray solutions.



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