The ocean surrounding the Antarctic continent is experiencing one of the fastest warming rates. Credit: Chao Ban.
Sea surface temperatures and deeper water temperatures have reached record new highs in 2024 highlighting further concerns about global warming.
A new study has found that ocean warming in 2024 has led to new record high temperatures. 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 metres.
Professor Lijing Cheng with the Institute of Atmospheric Physics at the Chinese Academy of Sciences, said: “The broken records in the ocean have become a broken record.”
Cheng led a team of 54 scientists from seven countries and discussed how a hotter ocean affects our lives on land and what this means for our future.
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 our weather patterns by transferring heat and moisture into the atmosphere.
The ocean also controls how fast climate change happens.
Co-author Professor John Abraham at the University of St Thomas, said: “To know what is happening to the climate, the answer is in the ocean.”
The ocean warming patterns are not uniform; regional variations can be substantial. Credit: Cheng et al.
Consistent
Results from three international teams who collaborated on this project were consistent – the ocean is warming, and 2024 was a record. The central message is that the values have been increasing year after year after year.
From 2023 to 2024, the global upper 2,000m ocean heat content increase is 16 zettajoules (1021 Joules), ~140 times the world’s total electricity generation in 2023.
Professor Michael Mann from University of Pennsylvania, said: “OHC has increased steadily by 15~20 ZJ over the past five years despite the La Niña and El Niño cycles.”
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.
Why does this matter?
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.
Another member of the team, Dr Kevin Trenberth, a senior scientist at National Center for Atmospheric Research, USA, said: “The main way the ocean continues to influence the climate is through accompanying increases in water vapor in the atmosphere that leads to the damaging increases in extremes in the hydrological cycle.
“Water vapour is also a powerful greenhouse gas and increased heating leads to drying and risk of drought and wildfire.
“But it also fuels storms of all sorts and leads to risk of flooding; that includes hurricanes and typhoons.”
For example, over the past 12 months, a staggering 104 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.
The heat in the ocean is the best measurement for monitoring the changing climate.
Co-author Dr Karina von Schuckmann, of Mercator Ocean International, said: “The ocean is our sentinel for planetary warming, acting as the major sink of surplus heat accumulating in Earth climate system as a result of anthropogenic emissions.”
If there continues to be a failure to take action to slow climate change, the disruption, unprecedented change and its implications, costs and loss and damages will continue to increase.
The study is published in Advances in Atmospheric Sciences.
