Overview

• In 2023 and 2024, the oceans experienced unusually intense and persistent marine heatwaves, with parts of the Atlantic in heatwave conditions for more than 300 days in 2023.
• The Baltic Sea is warming at more than three times the global average and the North Sea at about twice the global rate, according to the report’s 30‑year trend analysis.
• Germany’s BSH reported that temperatures in the southwestern Baltic, including German waters, were up to 1.5 C above the 1997–2021 summer average this year.
• Scientists warn that warmer seas are already fueling stronger evaporation that drives heavier rainfall and inland flooding, while sea‑level rise is increasing coastal inundation risks.
• Copernicus notes that ocean warming has accelerated since the 1960s and describes this as evidence of a dangerous Earth system imbalance; the EU‑funded service provides ocean analyses and forecasts.