Over the last 20 years, there has been twice as much sea level rise on Italy’s Amalfi coast as on Spain’s Costa del Sol, a study shows. Researchers combined data from tide gauges and satellites with ice melt measurements to model sea level change across the Mediterranean basin since 1960. To their surprise, they found that sea level fell by about 9mm between 1960 and 1989, owing to increased atmospheric pressure over the basin. But since 1989, ocean warming and land ice melting have driven rapid sea level rise, reaching an average rate of 3.6mm a year in the Mediterranean basin over the last two decades. The rise has not been spread evenly, however. Their findings, which are published in JGR Oceans, show that the Adriatic, Aegean and Levantine seas have risen by 8cm over two decades, while the Cretan passage in the eastern Mediterranean has risen by half this amount. They suspect that this uneven pattern is due to changes in water density and circulation patterns in the Mediterranean. This has implications for coastal engineering. “Structures like sea walls are effective but expensive. Reliable estimates of local sea level rise will help planners make cost-effective decisions,” says Francisco Mir Calafat, from the National Oceanography Centre in Liverpool.