Another year, another broken climate record. In 2022, an international team of scientists measured the hottest global ocean temperatures in human history.
This makes 2022 the seventh year in a row that ocean temperatures have reached new highs.
The record is based on two international timelines of ocean heat data dating back to the 1950s: one conducted by government researchers in the United States and the other by government researchers in China.
Both data sets show that ocean waters up to 2,000 meters (about 6,600 feet) deep are now absorbing 10 zettajoules (ZJ) more heat than they were in 2021. That’s one hundred times more energy than the global electricity bill every year.
Having what is called a high specific heat capacity, wWater is exceptionally efficient at absorbing huge amounts of thermal energy without rapidly increasing in temperature. In addition, the oceans contain a lot of water. But storing 10 ZJ in an ocean bank is not without consequences.
On Earth, the world’s oceans absorb 90% of the excess heat in our atmosphere, and like a sponge absorbs water, the effect fundamentally changes the density, dynamics and structure of the sea.
Today, the salinity contrast of the oceans has reached an all-time high. In the Pacific Ocean and the eastern Indian Ocean, scientists say seawater is getting cooler. But in the mid-latitude Atlantic Ocean, the Mediterranean Sea, and the western Indian Ocean, seawater becomes much saltier.
“Salty areas are getting saltier and cool areas are getting cooler, and so there is a continuous increase in the intensity of the hydrological cycle,” says climatologist Lijing Cheng of the Chinese Academy of Sciences.
In simple terms, this means that the layers of water in the ocean no longer mix as they used to, disrupting the natural circulation of heat, carbon and oxygen from the atmosphere above.
In 2022, for example, the heat content in the upper 2000 meters of the Pacific Ocean reached a record high “by far”, according to the researchers, “which confirms observed extreme events, such as intense heat waves and deoxygenation, and poses a substantial risk to marine life in this region.”
A reduction in mixing most likely triggered an event known as a “Blob”; a large, persistent pool of warm water in the Pacific Northwest that began circulating in 2013, devastating birds and sea life for years to come.
In 2022, the heat content of the oceans in this region reached its third highest level on record, which means we probably haven’t seen the last of the Blob.
It’s not just marine life that’s suffering either.
The ocean and atmosphere are closely linked, which means that warmer or saltier waters could strongly influence global weather patterns and sea level rise.
If warmer waters and saltier waters become too stratified in the ocean, there is a risk that the ocean will no longer be able to absorb as much carbon as before. Greenhouse gases would concentrate in the atmosphere, causing serious effects on the climate.
Earth’s salty water bodies have been called “the greatest ally against climate change” because they serve as a bulletproof vest against the worst blows of the climate. But there’s only so many hits the ocean can take before it falls, too.
Despite warning after warning, very little action was taken to curb the continued rise in greenhouse gas emissions, which meant that the oceans continued to absorb our worsening pollution.
Since the 1980s, researchers have found a three- to four-fold increase in the rate of ocean warming. In 2022, the level of stratification measured in ocean waters was among the seven best on record.
“Until we reach net zero emissions, this warming will continue and we will continue to break ocean heat content records, as we have done this year,” says climatologist Michael Mann of the University of Pennsylvania. .
“A better knowledge and understanding of the oceans is the basis of actions to combat climate change.”
An extreme climate is our reality and our future. The extreme is up to us.
The study was published in Advances in atmospheric science.