The coastal waters surrounding Europe are heating at an alarming rate faster than the global climate as a whole, according to a new report by World Weather Attribution.
An international team of scientists assessed water temperatures across four key coastal regions this summer, confirming a widespread marine heatwave stretching from Ireland to the Mediterranean Sea with some areas reaching up to 6°C hotter than normal.
World Weather Attribution is an academic collaboration that conducts rapid studies to analyze the influence of human-driven climate change on extreme weather and environmental events. By combining real-time observational temperature readings with computer climate models, researchers can calculate how much warming can be directly attributed to human activity.
Regional ocean warming measurements
In most of the evaluated regions, ocean warming over the summer surpassed the global average temperature increase of 1.4°C. Water temperatures in the Celtic Sea ran around 1.2°C higher than average, while surface temperatures in the Mediterranean Sea rose by up to 3°C above normal levels.
The research team found that climate change is the primary driver of the surge in temperatures across European waters. According to the attribution analysis, climate change has directly caused about 2°C of warming in the Mediterranean, 1.4°C of warming in the Bay of Biscay and Iberian Peninsula, and 1.3°C in the Celtic region.
The Celtic Sea is the area of the Atlantic Ocean situated off the southern coast of Ireland, while the Bay of Biscay borders western France and northern Spain along the Iberian Peninsula. These coastal regions host critical fish stocks, marine trade routes, and coastal economies that depend on stable ocean conditions.
Human impact on marine ecosystems
Dr Claire Bergin, a researcher at Maynooth University in Ireland, noted that while higher water temperatures might seem appealing to tourists in cooler climates, the ecological consequences underwater are far more severe.
Dr Bergin said: "This has been a remarkable summer for heat across Europe, but the impacts on our coastal waters are not as well reported."
She added: "Our attribution analysis shows that human-induced climate change has directly added about 2°C of heat to the Mediterranean to date and over 1.3-1.4°C to Western European seas."
Dr Bergin cautioned: "While warmer waters for swimming may sound appealing to beachgoers in cooler countries like mine, the impacts on marine life beneath the surface is more serious. This has the potential to completely reshape ecosystems that coastal communities rely on for food and income, and drive damaging extreme weather on land too."
Maynooth University is a public research university located in County Kildare west of Dublin. The institution operates dedicated environmental research centers examining North Atlantic climate trends and marine environments.
Professor Thomas Frölicher from the University of Bern in Switzerland pointed to fossil fuel consumption as the primary cause of the rising temperatures.
Professor Frölicher said: "From the Atlantic waters off Ireland to the Mediterranean sea, Europe's seas are experiencing an alarming surge in temperatures. Our research shows clearly that this is being driven by climate change, in particular by the continued burning of fossil fuels. Every very extra tonne of carbon we emit pushes Europe's coastal temperatures and ecosystems into uncharted territory."
The University of Bern, established in 1834 in Switzerland, hosts the Oeschger Centre for Climate Change Research, which conducts scientific studies on ocean dynamics and greenhouse gas emissions.
Severe risks to biodiversity and communities
Scientists warned that extreme marine heatwaves create serious consequences both above and below the ocean surface. Professor John Bruno from the University of North Carolina at Chapel Hill stated that extreme heat is disrupting marine environments.
Professor Bruno said: "Extreme ocean heat leads to mass mortality events of habitat-building species like corals, sponges, and macroalgae, causing cascading impacts through entire marine ecosystems."
He added: "While the range of some species moves north, others simply cannot escape. As ocean temperatures continue to climb, we are rapidly approaching the absolute biological limits of adaptation for many species, threatening biodiversity, fisheries, and coastal food systems."
The University of North Carolina at Chapel Hill is a leading public research institution in the United States known for marine ecology and coastal conservation research.
Professor Friederike Otto from Imperial College London highlighted the economic strain facing European communities dependent on the ocean.
Professor Otto said: "Many people and industries depend on the sea not heating up as fast as it is. In our oceans and seas there can be very hard limits for adaptation. The longer we wait with transitioning away from fossil fuels, the higher the price. A price not paid by the rich."
Imperial College London is a public research university specializing in science and medicine that co-leads the World Weather Attribution initiative.
The Paris Agreement emission targets
The rapid heating of European waters highlights the targets established under the Paris Agreement, an international accord signed in 2015 to limit climate change.
According to details from the European Commission, the treaty aims to keep the increase in global average temperature well below 2°C (3.6°F) above pre-industrial levels and to pursue efforts to limit warming to 1.5°C (2.7°F). Previous research cited by the report warns that 25 per cent of the world could experience significantly drier conditions if warming exceeds 1.5°C.
The European Commission outlines four core goals under the agreement regarding emission reductions:
- A long-term goal of keeping the increase in global average temperature to well below 2°C above pre-industrial levels.
- To aim to limit the increase to 1.5°C, since this would significantly reduce risks and the impacts of climate change.
- Governments agreed on the need for global emissions to peak as soon as possible, recognising that this will take longer for developing countries.
- To undertake rapid reductions thereafter in accordance with the best available science.
