Properly restored, coastal ecosystems can be self-sustaining. Infrastructure like sea walls, on the other hand, is expensive to construct and maintain, especially as ocean levels rise. Given enough space to creep inland, wetlands can adapt. “These systems can keep up pace with sea level rise, as long as they can migrate backwards,” said Emily Landis, global climate adaptation and resilience director at The Nature Conservancy, who wasn’t involved in the study. “That means they can still provide that essential adaptation, flood reduction benefit.”