New research finds that the amount of heat soaked up by the Earth’s oceans reached a record high for the sixth year in a row in 2022 — a show of the dire need to address the climate crisis to protect life as it is currently known on Earth.
Research published in Advances in Atmospheric Sciences on Wednesday shows that ocean heat content hit its hottest point in the historical record last year, with other indicators of the climate crisis, like ocean salinity and ocean stratification, also reaching record levels. Ocean heat hit such highs despite a La Niña event, which generally has a cooling effect, demonstrating the ability of the climate crisis to drastically disrupt global temperature cycles.
Climate change caused by human activity is the driving force behind many of these dangerous shifts, which threaten to destroy a wide variety of natural systems in and out of the world’s oceans. These changes are, in turn, an indicator of the stark upward trend of global warming.
“These cycles have been profoundly altered due to the emission of greenhouse gasses and other anthropogenic substances by human activities, driving pervasive changes in Earth’s climate system,” the authors wrote.
The study analyzed data from the top 2,000 meters of the Earth’s oceans, which gained about 14 zetta joules, or 14,000,000,000,000,000,000,000 joules, of heat last year. This is equal to about 145 times the world’s electricity generation in 2021.
The oceans’ heat is one of the most effective indicators of the climate crisis. Atmospheric temperatures tend to fluctuate year by year, while still showing an overall upward trend; research by the EU has found that last year was the world’s fifth-warmest year for global surface air temperatures, for instance. Ocean heat, on the other hand, has been steadily rising annually, as oceans absorb over 90 percent of excess warming caused by the relentless burning of fossil fuels and other warming actions across the globe.
This research could help explain why some of last year’s climate disasters, like Category 4 Hurricane Ian and devastating flooding in Pakistan, were so strong, as the ocean has literally been fueling these disasters.
“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,” said study co-author Kevin Trenberth. “This contributes to changes in the hydrologic cycle and emphasizes the interactive role that oceans play.”
The fact that oceans are warming so rapidly is an alarming indicator of the pace of global warming. “Oceans contain an enormous amount of water, and compared to other substances, it takes a lot of heat to change the temperature of water,” former Scripps Institution of Oceanography researcher Linda Rasmussen told The Washington Post. “The fact that we’re seeing such clear increases in ocean heat content, extending over decades now, shows that there is a significant change underway.”
Because ocean temperatures and conditions affect so many different systems, rising ocean heat comes with a variety of devastating consequences. Ocean habitats are being destroyed, killing biodiversity, while ice at the Earth’s poles is melting, even further accelerating warming. Along with this water flowing off of historic glaciers and ice caps into the sea, the absorbed heat is also causing oceans to physically expand, causing sea level rise that threatens to wipe out ecosystems and cities across the globe.
The study findings issue a strong mandate for global powers to act on the climate crisis, the authors said.
“The oceans are absorbing most of the heating from human carbon emissions,” said co-author Michael Mann. “Until we reach net zero emissions, that heating will continue, and we’ll 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.”