Continuous ocean temperature records, rising stratification, and shifting patterns of water salinity provide a glimpse into what the future may hold in a climate that is constantly warming.
The health of the oceans can be used to gauge how well the world is doing, and based on the most recent oceanic observations from 24 scientists at 16 different institutions around the world, there is a need for help.
Continued historical record-breaking temperatures, historically high levels of ocean salinity contrast, and accelerated ocean stratification (the division of the water into layers) are the three main indicators of climate change.
To better prepare the public for an extreme climate future, scientists are being prompted by these indicators to address and forecast future aspects of climate change as soon as possible.
A new record of 0–2000 m ocean heat content (OHC) was set and recorded in 2022, adding about 10 Zetta joules (ZJ) more heat to the ocean than in 2021, according to recently published results. A Zetta joule (a unit used to measure “work” or “heat”) is a joule with 21 zeros after it.
On January 11th, 2023, the findings were released in Advances in Atmospheric Science. It summarizes two international datasets that examine observations of ocean heat content and their effects dating back to the 1950s.
These datasets come from the National Centers for Environmental Information (NCEI) of the National Oceanic and Atmospheric Administration (NOAA) and the Institute of Atmospheric Physics (IAP) at the Chinese Academy of Sciences (CAS).
Both IAP and NCEI data show a consistent message that upper 2000m ocean heat content hits a record high value in 2022.
Tim Boyer, Senior Researcher, National Centers for Environmental Information, National Oceanic and Atmospheric Administration
A 10 ZJ of heat is equivalent to 100 TWH of electricity produced globally in 2021, 325 TWH of electricity produced in China in 2021, and 634 TWH of electricity produced in the United States in 2021 (4381 TWH). For the past year, 10 ZJ of heat could have boiled 700 million 1.5 L kettles per second.
Global warming continues and is manifested in record ocean heat, and also in continued extremes of salinity. The latter highlight that salty areas get saltier, and fresh areas get fresher and so there is a continuing increase in intensity of the hydrological cycle.
Lijing Cheng, Study Lead Author and Researcher, Institute of Atmospheric Physics, Chinese Academy of Sciences
It is simple to understand that the serious effects of that much heat entering the oceans will occur much sooner than one might anticipate. Heat, carbon, and oxygen exchange between the ocean and the atmosphere above it can change as the oceans become more salinized and stratified as a result.
This factor can result in ocean deoxygenation, or the water losing oxygen. For humans and terrestrial ecosystems, in addition to marine life and ecosystems, deoxygenation is a nightmare in and of itself.
Reducing ocean diversity and displacing significant species can have a devastating impact on communities that depend on fishing and their economies, which can then affect how most people are able to interact with their environment.
The effects of a rapidly warming ocean are already being felt in some areas, and they are not what was anticipated.
Some places are experiencing more droughts, which lead to an increased risk of wildfires, and other places are experiencing massive floods from heavy rainfall, often supported by increased evaporation from warm oceans. This contributes to changes in the hydrologic cycle and emphasizes the interactive role that oceans play.
Kevin Trenberth, Study Third Author and Researcher, National Center for Atmospheric Research
The delicate balance between our oceans and the atmosphere is partly disrupted because rising water temperatures and salinities cause water to layer rather than mix.
John Abraham, study second author and a professor at the University of St. Thomas added, “In the future, the group will focus on understanding the changes of the earth’s major cycles and improve the future projections of earth's heat, water, and carbon changes. This is the basis for human[s] to prepare for the future changes and risks.”
Scientists will be able to plan ahead for higher temperatures, more severe weather, and all other effects that come with warming oceans and a disrupted hydrologic cycle if they continue to monitor these changes.
Michael Mann, a study author and a professor at the University of Pennsylvania, further stated, “The oceans are absorbing most of the heating from human carbon emissions. Until we reach net zero emissions, that heating will continue, and we will continue to break ocean heat content records, as we did this year. Better awareness and understanding of the oceans are a basis for the actions to combat climate change.”
Cheng, L., et al. (2022) Another Year of Record Heat for the Oceans. Advances in Atmospheric Science. doi:10.1007/s00376-023-2385-2.