The length of ocean heat waves has tripled

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The study, a comprehensive assessment of the impact of the climate crisis on heat waves in the world's oceans, reveals profound changes that have occurred in recent decades. Warmer oceans absorb less and less of the carbon dioxide that raises temperatures.

Study leader Dr. Marta Marcos from the Mediterranean Institute for Advanced Studies in Mallorca said that heat waves in the Mediterranean are up to 5 degrees Celsius warmer than they were before the massive burning of fossil fuels.

In addition to destroying underwater ecosystems warmer ocean waters create ideal conditions for more powerful storms. One example was the intense rainfall that caused flooding in Libya in 2023 that killed 11,000 people.

The only solution is to reduce the burning of fossil fuels because over ninety percent of the additional heat captured by greenhouse gas emissions is stored in the oceans. If humanity stops warming the atmosphere it will stop warming the oceans too.

A very long heatwave occurred in the Pacific in 2014-2015 causing mass mortality of marine life. Another intense heatwave hit the Tasman Sea in 2015-2016. Also worth noting are the record sea temperatures around the UK and in the Mediterranean Sea in 2023. As early as 2019, scientists warned that ocean heatwaves were increasing rapidly and killing swaths of marine life.

Ocean heatwaves pose significant risks to society with individual events causing millions in losses to the fisheries aquaculture and tourism industries. The study published in the journal Proceedings of the National Academy of Sciences created a model of sea surface temperatures since 1940 that removed the warming caused by the climate crisis. They then compared it with actual measurements from the oceans to show how global warming has increased temperatures.

The analysis revealed that in the 1940s there were about 15 days of extreme heat per year on the ocean surface. This number has now jumped to a global average of almost 50 days per year. The Indian Ocean experiences extreme temperatures an incredible 80 days per year.

Seas in the tropics are already warm enough so any extra heat tends to prolong the duration of heatwaves. Dr Xiangbo Feng from the University of Reading who was part of the study team said that as global temperatures rise, heatwaves in the seas and oceans will become more common and severe. Human activities are fundamentally changing the oceans and urgent climate action is needed to protect the marine environment.

Source:Guardian