3rd Annual C4E Environmental Forum Ponders Managed Retreat vs. Coastal Defense

Elinor Adams and Erik Mesic of New York University debated whether managed retreat or coastal defense for flood protection is better for addressing sea level rise in New York City at the third annual Collaborative for the Earth Environmental Forum. Photos by John Griffin.

Understanding how to protect our natural world and the people in it in the face of a rapidly shifting climate is one of the most complex tasks modern science has ever undertaken. On April 3, Stony Brook's Collaborative for the Earth (C4E), the New York University (NYU) Debate Team and a distinguished panel of experts discussed whether humans can engineer their way out of a changing climate, or if it is time to step back from the shoreline.

"Today's environmental challenges don't belong to any one field or discipline, they are complex, interconnected and require interdisciplinary expertise, thinking and cooperation," said Kevin Reed, associate provost for climate and sustainability programming at Stony Brook. "That's exactly what C4E was designed for, to foster collaborations to take on problems that are larger or more complex than any one unit on campus or any one degree program."

Melissa Finucane, Stony Brook University's inaugural William and Jane Knapp Endowed Infinity Chair and an expert in applied climate change response planning, moderated the discussion.

"There are no easy answers to any of these complex challenges that climate change poses to communities and our natural resources," said Finucane. "But what we do know is that as we navigate the steep environmental and social transitions that are needed, we have to integrate a lot of different types of information, social, physical and natural science, as well as diverse views and values that stakeholders bring from their real-world experience. Whether we choose to retreat or adapt or defend our coastlines, there are multiple risks and benefits that we have to integrate and trade off as we chart a path forward."

Sara Hamideh, associate professor in the School of Marine and Atmospheric Sciences and Tyler Taba, director of Policy and Government Affairs at the Waterfront Alliance.

The student debate featured NYU's Elinor Adams and Erik Mesic discussing whether managed retreat or coastal defense for flood protection is better for addressing sea level rise in New York City. Adams argued managed retreat is more cost-effective and long-term, while Mesic emphasized coastal defense's immediate benefits and customization for vulnerable communities.

"New York relies on an underground public transport system, especially prone to flooding during hurricanes," said Adams, a pre-law student studying Environmental Justice and Philosophy at NYU Gallatin School of Individualized Study. "Some argue that the city's current subway opening protection measures can effectively prevent subways from flooding, but all 3,500 of them have to be sealed on time, or this flood reduction is moot. Simultaneous sealing and other facets of coastal defense represent policymaking trapped in self-denial."

Adams also cited the expense of investing in coastal defense. "The city is spending billions on flood infrastructure that they recognize is not a permanent solution," he said. "This infrastructure costs a lot of money, and it's not absolute."

Mesic, a business major at NYU Stern School of Business, presented the case for coastal defense, citing two fundamental reasons: project innovations and displacement. "The Mayor's Office for Climate and Economic Justice describes in a 2026 report that the neighborhood coastal flood protection project, a large-scale capital effort that mitigates coastal flood risk for an entire neighborhood, massively reduces cost and customization and is designed for each community's unique characteristics."

Alison Branco, director of the Climate Adaptation Program for The Nature Conservancy in New York, Sara Hamideh and Tyler Taba.

Mesic said that regardless of the area, the project reduces exposure to coastal storm surge and tidal flooding, prevents shoreline erosion and helps with interior drainage.

"The second argument is about displacement. Who gets displaced and why? In a managed retreat system, that will not be left up to the people who are displaced, but instead to politicians, business leaders and elite decision-makers whose homes won't be at stake at all. So even if some sources say that managed retreat is better, the displacement methods never will be because there's no system that alters existing power dynamics."

The panel of experts included Sara Hamideh, associate professor in the School of Marine and Atmospheric Sciences at Stony Brook University; Alison Branco, director of the Climate Adaptation Program for The Nature Conservancy in New York; and Tyler Taba, director of Policy and Government Affairs at the Waterfront Alliance.

Branco mentioned the time investment in implementing infrastructure defenses.

"Both speakers talked about permanence versus immediacy," said Branco. "None of these building-engineered defenses are fast. There's a big project happening in New York City right now and the timeline goes out to 2045. Sometimes you do have to build hard infrastructure to protect people and other infrastructure, but we need to use the time to have the hard conversations that people are avoiding. The long-term, like it or not, will have a lot more water."

Hamideh, the only academic researcher on the panel, said the very premise of the debate offered a false choice.

"The setup of this debate is 'Option A vs. Option B,' but I don't think that is the right question to ask," said Hamideh. "We should be asking 'what is the best combination of A, B, C, D, all the way to Z."

Hamideh said there are innovations that are going to be less costly compared to managed retreat and engineered defenses.

"There are so many innovations in the land use and property ward that we are not even talking about," she said. "So when we talk about these options, the reality is that what the actual communities are dealing with is not A versus B, they are thinking about many different considerations. To do justice to them, and as experts, we need to give them fair assessments of a combination of different options."

"I think there is an unrecognized cost of maintenance and operations of parks and green infrastructure assets that also isn't taken seriously by New York City," said Taba. "I think it's an issue across the country where we don't invest enough in our infrastructure."

Like his fellow panelists, Taba also addressed the issue of equity.

"We've touched on equity, but what's missing from the conversation is 'who's in the floodplain, who's at risk, and how did that happen?'" said Taba. "Some of it is by accident, but a lot of it is not. There have been policies that actually put people in the floodplain disproportionately through redlining and other forms that have made those places that were once-upon-a-time not so desirable. But saying that people need to relocate can help perpetuate the underinvestment that these same communities have long suffered."

"Technically we're debating which is more expensive," said Branco. "I think intuitively we all know that that's not sufficient, so I do think we're creeping toward a place where we're making a more holistic decision. Hopefully when we get to that point we'll do a better job finding the right combination of solutions."

"Over the past year, the collaborative for the Earth has continued to host a wide range of events," said Reed. "All of this is aimed at sparking thoughtful dialog around these topics. These efforts reflect core belief that real progress begins where open and sustained conversations, especially around difficult and nuanced topics. Today's forum is a wonderful example of that mission and action."

- Robert Emproto