The installation of structures to protect against coastal threats, called shoreline hardening, is a common practice worldwide, with many coastal cities having 50% or more of their shores protected against floods and erosion. Despite increasing evidence of negative ecosystem effects, shoreline hardening is expected to continue as growing coastal populations scramble to address rising seas and severe storms. For this episode of BioScience Talks, we spoke with Dr. Rachel Gittman of Northeastern University. Gittman and her colleagues recently conducted a meta-analysis of 54 existing studies on shoreline hardening. The results, described in the journal BioScience, highlight a stark impact to biodiversity but also point to approaches that may mitigate the harm.