According to the European Space Agency (ESA), the seas around the UK and Ireland have experienced notable and significant rises in marine heat. In certain regions, water temperatures have exceeded the average for this time of year by as much as 3 to 4 degrees Celsius, as analysed by ESA in conjunction with the Met Office.
Off the east coast of the UK, spanning from Durham to Aberdeen, and also off the north-west coast of Ireland, the sea is particularly warm. The Met Office suggests that human-induced climate change is partially responsible for this phenomenon. However, there are other factors, both natural and man-made, that contribute to the escalating temperatures and are not yet fully understood.
The occurrence of warm seas around the UK coincides with a broader trend of rising air and ocean surface temperatures worldwide, which have exhibited a notable spike in recent months. According to the Met Office’s historical data dating back to 1850, global sea surface temperatures for both April and May have reached unprecedented levels, establishing new records. This indicates a significant and concerning warming trend on a global scale.
In May, the ocean temperature, on average, was 0.85 degrees Celsius higher than the normal conditions for that month, as reported by the US National Ocean and Atmospheric Administration. This rise in ocean temperatures has coincided with a series of extreme heat events observed worldwide. These unusually high temperatures have played a role in exacerbating and fueling devastating wildfires, such as the record-breaking ones in Canada. The impact of these fires caused smoke to spread as far as New York and other cities in North America.
Scientists caution that such intense heat can have devastating effects on marine life, potentially resulting in large-scale fish and other sea creature mortality. Moreover, marine heatwaves, characterised by prolonged periods of abnormally high sea surface temperatures, are linked to the amplification of extreme weather events. Storm systems, fueled by the increased energy from warmer waters, can become more intense and persist for longer durations.
While the current high temperatures may be temporary, it is important to note that the 1.5 degrees Celsius threshold refers to average temperatures over a 20 or 30-year period. However, experts anticipate that more temperature records will be broken in the coming months due to the expected warming of the Pacific Ocean as a result of an El Niño event.
El Niño is a powerful climate fluctuation that occurs globally. The El Niño Southern Oscillation is entering its warm phase, during which warm waters rise to the surface off the coast of South America and spread across the ocean, significantly contributing to heat transfer into the atmosphere. This process can lead to further warming effects and potentially impact weather patterns and temperatures across various regions of the world.
El Niño is known to cause cooling in the Atlantic Ocean, so there is a chance the natural phenomenon could aid in reducing the abnormally high water temperatures surrounding the UK and other parts of Europe. However, due to the record-high temperatures, larger and more severe storms are more likely to occur in the area.
Besides global warming, one factor causing the temperature increase could be the effects of a reduction in pollution from shipping. Regulations reducing the sulphur content of fuel burned by ships were brought in by the International Maritime Organization (IMO) in 2020. This significantly reduces the amount of aerosol particles released into the atmosphere, the IMO said. But aerosols that pollute the air can also help reflect heat back into space, so removing them may have caused more heat to enter the waters.
The impacts of the exceptional temperatures in the North Atlantic are already taking shape. The eastern tropical Atlantic is the main spawning ground for North Atlantic hurricanes and the Met Office says an Atlantic tropical storm looks likely to form east of the Caribbean by the middle of this week.
The Met Office says it can be expected the hot weather will continue. There is a 45% chance, which is significantly higher than usual, that the UK will have what it describes as a “hot summer.”
