THE INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE FOURTH ASSESSMENT REPORT (1) LARGELY overlooked the impacts of climate change on marine ecosystems (2). In their Review (“The impact of climate change on the world’s marine ecosystems,” 18 June, p. 1523), O. HoeghGuldberg and J. F. Bruno redress this gap by synthesizing recent literature. In so doing, they made the disparities in research among ocean systems apparent. Specifi cally, there are no studies of climate change impacts to sandy beach ecosystems. Rather than any oversight by Hoegh-Guldberg and Bruno or previous authors (3), we believe that the omission of beaches from this and other assessments of anthropogenic impacts reflects a relative lack of appreciation of beaches as ecosystems. This paucity of beach studies (4, 5) is alarming, not only because beaches comprise ~70% of open-ocean coasts and have high socioeconomic and ecosystem value, but also because their position at the land-sea margin renders them highly vulnerable to climate change (5, 6). Beaches are at risk of signifi cant habitat loss and ecological impacts from warming, acidification, and erosion caused by sea-level rise and increased storms. Where landward retreat of beaches is restricted by development or topography, beach habitat may disappear. When engineering interventions seek to mitigate beach erosion, negative ecological consequences may be severe but are only beginning to be understood (6, 7). The inadequacy of information
on ecological impacts of climate change on this vulnerable and challenged coastal ecosystem must be addressed.