Rapid sea heating could be evidence of ‘hidden climate risks’

A study published last week has shone a light on an alarming increase in marine temperatures across the world, as experts warn this year’s El Niño weather event will be hotter than normal. 

Research by a team led by Dr. Karina Von Schuckman, a specialist in ocean climate monitoring at Mercator Ocean International in Toulouse, France and member of the European Academy of Science, has identified a recent, rapid increase in sea temperatures. 

Over the past month, oceanic thermometers broke records, with North America’s East Coast averaging at 13.8C higher than the 1981-2011 average during March 2023. If sustained at these levels, the risk to ecosystems is significant, but the real worry is the impact of a stronger-than-usual El Niño as predicted by meteorologists. 

The annual weather event – translated into English from Spanish as ‘The Boy’ – is the warm phase of the El Niño–Southern Oscillation (ENSO) and refers to a band of warm water that develops in the central and east-central equatorial Pacific Ocean.

It is associated with high air pressure in the western ocean, low in the east, and works in cycles lasting approximately four years. Reports suggest that if this system does develop this year, it could mean 2023 beats 2016 to become the hottest since records began. In the past 15 years alone, Earth’s accumulated heat has increased by 50%, and the majority of this been stored in the ocean, leading to mass loss of life, extinction of species, and catastrophic ecosystem events, such as mass bleaching of coral at the Great Barrier Reef. 

Currently, it remains a mystery why recent weeks have seen such a significant spike in oceanic temperatures. However, one theory is particularly alarming – a reduction in levels of sulphur in shipping fuel, designed to try and protect marine life, has left cleaner seas, which are more susceptible to warming from direct sunlight.

If this is true, it would be a significant example of how complex the task of trying to tackle the climate crisis is. While ‘tipping points’ usually refer to the natural chain reactions, it has long been hypothesised that some of the damage humans have caused the world is actually masking the danger posed by other climate issues. You can read the full study here.

Image: Joseph Barrientos

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