Map showing sea surface temperature anomalies on the 18th June 2023 compared to the average temperatures between 1985 and 2005. Areas of the North Sea off the coast of the northeast UK, the Atlantic Ocean off the northwest coast of Ireland and parts of the Baltic Sea were experiencing an extreme marine heatwave, with temperatures more than 5 degrees Celsius higher than average for the time of year. This warming is thought to be driven by the El Nino weather phenomenon and human-induced climate change. Marine heatwaves have harmful impacts on the marine ecosystem and threaten marine biodiversity. Data from the EU Copernicus Marine Service Information.