The ocean is the hottest it has ever been recorded by humans, not only at the surface temperature but also for the upper 2,000 meters, according to a new study co-authored by John Abraham, a mechanical engineering professor in the School of Engineering at the University of St. Thomas in Minnesota. The study, published in Advances in Atmospheric Sciences, found that ocean warming in 2024 led to new record high temperatures.
From 2023 to 2024, the global upper 2000 meter ocean heat content increase is 16 zettajoules (1021 Joules), ~140 times the world’s total electricity generation in 2023.
“To know what is happening to the climate, the answer is in the ocean,” Abraham said.
A team of 54 scientists from seven countries, led by Professor Lijing Cheng with the Institute of Atmospheric Physics at the Chinese Academy of Sciences, measured the ocean temperatures across various points for a year and the temperatures have steadily increased year over year. The measurements from the three international teams who collaborated on this project were consistent – the ocean is warming, and 2024 was a record.
“The broken records in the ocean have become a broken record,” Abraham said.
Why is the ocean so important?
The ocean is a critical part of the Earth’s climate – most of the excess heat from global warming is stored in the ocean (90%) and the ocean covers 70% of the Earth’s surface. Because of this, the ocean dictates weather patterns by transferring heat and moisture into the atmosphere. The ocean also controls how fast climate change happens.
The ocean surface temperature is also setting records. The surface temperature refers to temperatures just at the surface, where the ocean waters and atmosphere commute. Surface temperatures are important because they dictate how fast heat and moisture (humidity) can transfer from the ocean to the air and thus affect weather. The rise in surface temperatures since the late 1950s has been staggering.
Regional differences in temperatures
The changes are not uniform; regional variations can be substantial. The Atlantic is warming along with the Mediterranean Sea, and across the mid-latitude Southern Ocean. While parts of the Northern Pacific Ocean have warmed very rapidly, other areas (the tropical region) have not, mostly due to the La Nina/El Nino cycle in that area. The heat has even accumulated near both the North and South Poles.
A warmer ocean affects marine life and result in huge damage in many ways.
For example, over the past 12 months, a staggering 138 countries have recorded their hottest temperatures ever. Droughts, heat waves, floods, and wildfires have impacted Africa, Southern Asia, the Philippines, Brazil, Europe, the USA, Chile, and the Great Barrier Reef, as just but a few examples. Since 1980 for example, climate disasters have cost the USA nearly $3 trillion.
