News Release

The case for managed retreat

In an article in the journal Science, researchers make the case for managed retreat for vulnerable communities in the face of climate change

Peer-Reviewed Publication

Stanford University


image: This is flooding in the coastal city of Cebu, Philippines. view more 

Credit: J Lloa

Stanford, CA (Aug 22, 2019) -- As sea levels rise, many communities will be forced to relocate or be swallowed by the sea. Yet, retreat--relocation of communities in response to natural hazards and climate impacts--remains immensely controversial, and getting people and governments to plan for it is an uphill battle on several fronts. Below, researchers A.R. Siders, Miyuki Hino and Katharine Mach discuss their related article, published in the journal Science, on why, where, when and how communities should plan for retreat. Siders was an Environmental Fellow at the Harvard University Center for the Environment and is now an assistant professor at the University of Delaware. Hino is a Ph.D. candidate in Stanford's Emmett Interdisciplinary Program in Environment and Resources. Mach served as director of the Stanford Environment Assessment Facility and is now an associate professor at the University of Miami.

How can societies change the narrative of failure around retreat?

Siders: Fighting the ocean is a losing battle. The only way to win against water is not to fight. We need to stop picturing our relationship with nature as a war. We're not winning or losing: we're adjusting to changes in nature. Sea levels rise, storms surge into floodplains, so we need to move back. We can do that the hard way, by fighting for every inch and losing lives and dollars in the meantime. Or we can do it willingly and thoughtfully and take the opportunity to re-think the way we live on the coasts. This is why retreat needs to be strategic as well as managed. Retreat is a tool that can help achieve societal goals like community revitalization, equity, and sustainability if it is used purposefully.

Mach: The changing climate has transformations underway and in store, whether it's from risks of fire, drought and desertification, sea level rise, extreme heat, or heavy rain. To keep communities vibrant and safe, changing the narrative may be one of the most empowering tools societies have at their disposal. As Marine Corps Gen. Oliver Smith once said, "We're not retreating, we're just advancing in a different direction."

What are the biggest barriers to managed retreat?

Hino: No matter the circumstances, moving is hard. People have chosen where to live for a reason, and it is often difficult to find a place to move to that meets all their social, cultural, and financial requirements. One major challenge with retreat is that we're so focused on getting people out of harm's way, we miss the chance to help them move to opportunity. There are financial constraints as well. With limited resources, government agencies have to decide whether to try to reach more households, providing less to each, or try to fully support a smaller number of households. But there are certainly opportunities to tackle both of these challenges and find low-cost measures that give people a reason to be excited about their destination.

Siders: The biggest barrier to retreat is that there are short-term benefits to building and living in risk-prone areas. People like living in these areas - along the coasts, on riverbanks, in fire-prone wilderness. Developers make fortunes building new properties in risk-prone areas, which provide local governments with increased property tax revenue. Some people aren't aware of the risks, while others choose to ignore them because they have insurance, believe floodwalls or stilts will protect them, or just feel lucky. Some people don't have much choice because they have jobs nearby or can't afford housing in safer areas. It's a complicated mix of psychological, economic, and social issues. To address these issues, managed retreat needs to be embedded in larger conversations and social programs. Policies that give people incentives to stay need to be reformed. Programs need to give people reasons to leave. Retreat can't be just about avoiding risk: it needs to be about moving towards something better.

What are the social justice concerns regarding retreat?

Hino: One of the enduring questions is whether the residents "get to" relocate or "are forced to" relocate. In some cases, providing financial assistance for the most vulnerable households to move to safer ground will mean a fresh start. In others, it might equate to forced relocation, disrupting the social fabric that ties communities together and reinforcing existing inequities. Implementing retreat equitably requires taking a context-specific approach and putting the households and communities first.

Siders: If people have to move without any government assistance, people with the most resources are likely to move first, leaving the most vulnerable people in the most at-risk areas. When those people finally have to leave, the financial losses could be devastating. This could also happen if retreat is managed in a way that helps the wealthy first or is not paired with other social programs like building affordable housing in safe places.

How do you manage retreat?

Mach: In the United States, the most common approach to date has been buying out homeowners after disasters and then restoring the land to open floodplain. A few communities have aimed to relocate in their entirety in response to cyclones or gradual land loss and erosion. And there are also more subtle nudges: the ways that requiring setback from the ocean or public access to the beach has encouraged development that makes way for tides, storm surge, and seasonal replenishment of sand and sediments on the shore. Moving forward, there are important opportunities to innovate the "how" of retreat, building from these past experiences.

Siders: How you manage retreat depends on what you want to achieve and the local context. Of course, retreat is about adapting to climate change and reducing risk exposure, but is the program meant to help people who survived the last disaster, people who will be at risk in the future, or people with the fewest resources to move on their own? Will the land be used to create one large wetland to absorb floodwaters or a series of small community gardens spread throughout town? Retreat isn't an end in itself. It's a way to achieve other goals.

What future research needs to be done to improve strategic retreat?

Siders: Retreat needs experimentation - creative solutions developed by practitioners and rigorously tested by scientists to learn what works and what doesn't. Retreat is already happening - sometimes strategically, sometimes not. To be more strategic, retreat needs to be included in much larger conversations, such as how we build affordable housing, deal with social justice, integrate green spaces in urban landscapes, and develop larger cities in a more sustainable fashion. Retreat can be a tool in working towards those goals, if it is part of the conversation.

Mach: The story of retreat as a climate response is just beginning. Retreat is compelling because it brings together so many aspects of how societies work, what individuals are trying to achieve, and what it takes to ensure preparedness and resilience in a changing climate. Retreat is an adaptive option at the intersect of changing disaster risk, market forces, societal investments, and community well-being. There are exciting opportunities to better combine these drivers in research. To support deployment, there are intriguing possibilities for integrating data-rich analytics in the participatory processes in which people are defining their goals, assessing their options, and learning through time as they take action.


Siders was previously an Environmental Fellow at the Harvard University Center for the Environment and is now an assistant professor at the Disaster Research Center, University of Delaware. Hino is a Ph.D. candidate in the Emmett Interdisciplinary Program in Environment and Resources (E-IPER) at Stanford University. Mach previously served as director of the Stanford Environment Assessment Facility at the Stanford Woods Institute for the Environment and a senior research scientist at Stanford's School of Earth, Energy & Environmental Sciences. She is now an associate professor at the University of Miami Rosenstiel School of Marine and Atmospheric Science and a faculty scholar at the UM Abess Center.

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