All official European Union website addresses are in the europa.eu domain.
See all EU institutions and bodiesDo something for our planet, print this page only if needed. Even a small action can make an enormous difference when millions of people do it!
The total duration of marine heatwaves index represents the number of days in a year within prolonged periods of exceptionally high sea temperature values, defined as a period of at least 5 consecutive days with an SST above the 90th percentile and computed over an 11-day window centred on the same calendar day for a reference period. Variants of the index can adopt other heatwave definitions and different percentiles as thresholds to identify extreme conditions depending on the specific application. If daily data are not available, it is also reasonable to calculate the index using monthly data.
Index factsheet (ETC/CCA Technical Paper): Duration of marine heatwaves
The index is mainly relevant for the management of marine ecosystems and fisheries. However, the rather complex definition of the index can make its interpretation difficult.
As a consequence of mean ocean surface temperature warming, marine heatwaves have become more frequent globally and in European seas over the past century, leading to a considerable increase in the total duration of marine heatwaves, especially in the Mediterranean Sea. Marine heatwaves are projected to further increase in frequency, magnitude and duration. Under a high-emissions scenario (representative concentration pathway (RCP)8.5), the duration of marine heatwaves is projected to increase at least 20-fold along the European coastline; the increase is expected to be much smaller under a low-emissions scenario (IPCC, 2018: Extremes, Abrupt Changes and Managing Risks).
Chapters of the Europe's changing climate hazards report
For references, please go to https://www.eea.europa.eu/publications/europes-changing-climate-hazards-1/open-ocean/open-ocean-marine-heatwave or scan the QR code.
PDF generated on 07 Oct 2024, 05:37 AM
Engineered by: EEA Web Team
Software updated on 26 September 2023 08:13 from version 23.8.18
Software version: EEA Plone KGS 23.9.14
Document Actions
Share with others