Marine Heatwave Sweeps North Atlantic in Unprecedented Event

The US National Oceanic and Atmospheric Administration has classified the marine heatwave in the shallow seas around the UK and Ireland as a "Category 4" heatwave, which is rarely used outside of the tropics and means "extreme" heat. The heatwave is strongest in the northern North Sea, northwest of Ireland, and the Celtic Sea between Cornwall and southern Ireland, with surface water temperatures 4°C to 5°C above normal for mid-June. This could potentially harm fish and plankton populations, which are dependent on nutrients mixed up from the deep water into the surface layer. Climate change is already affecting these seas, and this extreme heatwave may be a sign of further changes to come.