This blog was originally posted on the World Bank's Sustainable Cities blog.

Heavy rain and severe flooding brought the city of Colombo, Sri Lanka, to its knees. In China’s Yangtze River Basin, rivers spilled their banks, inundating towns and villages. In Mobile Bay, Alabama, strong ocean waves carried away valuable coastline.

In each of these locations, disasters caused by natural hazards seemed beyond human control. But instead of focusing only on building more drains, seawalls and dams, these governments turned to nature for protection from the disasters. Several years later, the urban wetlands, oyster reefs and flood plains they helped establish are now keeping their citizens safe while nourishing the local economies.

Rising weather extremes, combined with increasing development along rivers and coastlines, are leading to a surge in impacts from climate-related disasters. Increasingly, governments are turning to nature to help manage these disasters. “Nature-Based Solutions” (NBS) that strategically conserve or restore nature (sometimes called ‘green infrastructure’) while supporting conventionally built infrastructure systems (‘gray infrastructure’) can reduce disaster risk and produce more resilient and lower-cost services in developing countries. Such solutions include widening of natural flood plains, protecting and expanding wetlands, restoring oyster and coral reefs and investing in urban green spaces that reduce run-off.

Evidence from around the world shows that these approaches are often successful and cost-effective. In the United States, natural wetlands have moderated damages from Hurricane Sandy by an estimated $625 million. Vietnam has implemented a widespread mangrove restoration project integrated with dike systems to reduce coastal flooding—which ultimately saved US$215 million. The City of Portland, Oregon has reduced urban flooding by up to 94 percent through urban green infrastructure, yielding US$224 million in savings to water infrastructure alone. Meanwhile, China’s “Sponge Cities” program in 30 pilot cities is integrating vast amounts of green space into urban design to prevent surface flooding. In addition to effectively reducing disaster risk, nature-based solutions can have a wide range of positive effects on ecosystem conservation, carbon storage, tourism and local employment.

The World Bank and the Global Facility for Disaster Reduction and Recovery (GFDRR) are stepping up their support for nature-based solutions (NBS). Over the past seven years, the Bank’s DRM portfolio totaled over US$50 billion across 681 projects.  The NBS components of World Bank disaster risk management (DRM) projects now total $2 billion, and just over 1 in 10 of the Bank’s DRM projects contain some element of NBS. All of these projects can be explored through the Natural Hazards, Nature-Based Solutions platform.

As more disaster risk managers understand and integrate well-designed nature-based solutions into disaster risk management projects, we can route more finance to nature-based projects that are cost-effective and resilient.

With that goal in mind, the World Bank, GFDRR, the Program for Forests (PROFOR) and the World Resources Institute (WRI) have teamed up to produce new actionable tools:

  1. A Practical Booklet outlining the World Bank and GFDRR’s Nature-Based Solutions program, featuring a range of practical nature-based solutions for the main climate hazards, and recommendations for financing and policy.

  2. A set of PowerPoint decks providing an overview of NBS, as well as how to use NBS for coastal risk managementriver flood control and urban disaster risk management

  3. An updated website with a global inventory of NBS projects and implementation guidance

Using these tools will provide disaster risk managers with illustrative examples on when and where nature-based solutions can add value to disaster risk management. It will also highlight policy and finance considerations which are somewhat different from traditional disaster risk management projects. For example, nature-based solutions are often more successful in environments where policies require different government sectors to work together, or where incentives have been set up for participation in nature-based solutions.  

While these materials should help the disaster risk management community get started on implementing more nature-based solutions, we need to develop more guidance and tested approaches to assess nature-based solutions on equal footing with traditional disaster risk management strategies. The World Bank, GFDRR and partners will continue to develop innovative case studies and work on the integration of these approaches in programs such as the City Resilience Program and the Small Island States Resilience Initiative. As a result of these efforts, we hope to see a world where we can tap nature’s full power to better protect us from disasters.