Increased marine heat waves, a major impact of climate change in the Mediterranean

Presented at the GHRSST XXIII international science team meeting, 27 June-1 July 2022, online and in-person (Barcelona). #GHRSST23

Short abstract

Mediterranean Sea has suffered an accelerated warming in the most recent 40 years. This warming has brought higher temperatures especially in the extended summer season in the Western Mediterranean (WMED), not only higher extremes but also persistent high values. Alongside, an increase has also be seen in the frequency and intensity of marine heat waves. From the analysis of satellite sea surface temperature (SST) data from GHRSST Level 4 AVHRR_OI Global Blended Sea Surface Temperature Analysis (GDS2) database main characteristics and specially trends of marine heatwaves have been analysed in the Western Mediterranean.

Marine heatwaves’ characteristics and trends for the whole WMED and subregions, previously defined by the authors in a former publication, have been studied. A global positive/increasing trend has been found for the occurrence, duration and intensity of marine heatwaves in the WMED, but relevant regional differences arise. Northern and central areas of the WMED show the highest increase of duration and intensities while the Alboran Sea area shows the lowest values in all analysed magnitudes. The area between the Gulfs of Lion and Genoa stands out as a hotspot in the for marine heat waves occurrence in the region. Differences appear not only from a regional point of view but also between seasons with clearly higher trend values for the extended summer season.