Upper ocean temperatures break records for sixth year, disrupting marine ecosystems

(CN) — Ocean temperatures across the globe rose for the sixth straight year.

According to research published Tuesday in the journal Advances in Atmospheric Sciences, scientists at 14 institutes around the world found that 2021 broke the record for heat accumulated in the upper ocean. The upper ocean absorbs 20 to 30% of human carbon dioxide emissions.

“The ocean heat content is relentlessly increasing, globally, and this is a primary indicator of human-induced climate change,” said paper author Kevin Trenberth, a distinguished scholar at the National Center for Atmospheric Research.

Trenberth said in an interview the impacts of the rising ocean temperatures could have serious ramifications throughout the planet. He noted that the increasing temperatures allow the atmosphere to leach more moisture. This increases the severity of wildfires and droughts in areas already at risk, while increasing the strength of storms, hurricanes and floods in other areas.

The threat to marine life and ecosystems is also severe. Trenberth said rising temperatures in the upper ocean can exacerbate ocean stratification where the different levels of the ocean do not mix as well, thus inhibiting the exchange of vital oxygen and nutrients between the depths and the shallows. Trenberth further noted the impacts of marine heat waves on populations of fish, whales, seals and other marine species.

The 23 researchers used two international datasets from the Institute of Atmospheric Physics and National Centers for Environmental Information, which help scientist analyze the ocean heat content back to the 1950s. According to a statement accompanying the report, they found that in the last year, the upper layer of the ocean — about 6,560 feet — absorbed 14 more Zettajoules than in 2020. This is equal to 145 times the electricity generated globally in 2020. All energy humans use across the world in a single year is about half a Zettajoule.

Trenberth said the research shows climate change is “keeping apace.” He said measures like the United Nations’ climate summit in Glasgow and international agreements including the Paris Climate Accords have failed to mitigate the accumulating ocean heat.

Going forward, Trenberth said more research would be done on expanding climate models, which he said have not been perfected. He and other researchers want to improve their understanding of warming’s effects on the ocean depths. He said this would allow researchers to “forecast out a week, a month, a year, ten years” and more, lending further accuracy to climate change trajectories.

“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,” said paper author Michael Mann, professor of atmospheric science at Pennsylvania State University, in a statement. “Better awareness and understanding of the oceans are a basis for the actions to combat climate change.”