The seasonal rise and fall in sea level along the US Gulf coast has grown more pronounced since the 1990s compared with earlier decades, probably because of warmer summers and colder winters.

Thomas Wahl and his colleagues at the University of South Florida in St Petersburg compared sea-level measurements collected between 1900 and 2011 with atmospheric data for the Gulf of Mexico coastline. They found that typical differences in sea level between summer and winter have increased during the past two decades.

Higher summer sea levels could increase the chances of hurricane-related flooding, and even slight changes in both summer and winter sea levels may affect sensitive ecosystems, the authors say.

Geophys. Res. Lett. (2014)