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A recently published research has analyzed more than 100,000 seawater samples worldwide and found that oceans absorb about 31% of carbon emissions from humans. It's "a huge ocean service," says a co-author in Seattle.
Richard Feely spent several years of his career at sea dumping packages of plastic tubes and drawing seawater from the depths of the sea while exploring the effects of carbon emissions on the world's oceans.
Feely, principal investigator at the Pacific Marine Environmental Laboratory of the NOAA (Ocean and Atmospheric Environment Administration) in Seattle, sampled the waters of the Antarctic, crossed Tahiti and overcame "huge" storms aboard ships ocean class research.
Most days on these scientific cruises, which last more than a month, there is no other boat in sight.
"You see a whale or birds on the occasion," he said. "It's a big ocean."
It is a painful and tedious job.
But the data collected by Feely and other scientists around the world now tell us just how much carbon that humans have shed in the ocean and what that could mean for our future.
Research published Thursday in the peer-reviewed journal Science analyzed more than 100,000 seawater samples collected worldwide from 1994 to 2007 and collected from almost every corner and every depth of the ocean.
The analysis revealed that the oceans absorb about 31% of the carbon that humans release into the world. As a reminder, the weight of carbon that seeps into the ocean each year, on average for the study period, equates to about 2.6 billion Volkswagen Beetle cars, Feely said.
It's "a huge ocean service," said Feely, co-author of the study. "This significantly reduces the overall temperature."
But this thermal protection has a cost. The ocean has continued to acidify and changes in its chemistry are already affecting the ecosystems of the Pacific Northwest. The addition of carbon lowers the pH of the seawater, making it more corrosive. Research by Feely and other researchers has revealed that carbon uptake in the world's oceans has kept pace with global CO2 emissions into the atmosphere.
"The amount of carbon in the ocean, this rate increases, because the amount of CO2 we emit into the atmosphere always increases," Feely said.
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For scientists, the results of the Science study were less a revelation than an affirmation. Thousands of physical measurements painstakingly collected for 13 years in almost every stretch of the ocean corresponded to what they already knew.
"The oceans have recently absorbed carbon dioxide exactly as we thought expected," said Curtis Deutsch, an associate professor of oceanography at the University of Washington, who did not participate in the research.
"The results are not really surprising, but they are extremely important to confirm that we really understand the system and how it works."
Scientists have long relied on climate models to predict our future of warming. In the ocean, models take into account factors such as circulation, biological processes and the chemistry of carbon dioxide and water.
"These models have all proven to be accurate and this is a fundamental step in the scientific process: you have to check predictions based on the basic principles of ocean circulation," said Deutsch.
These circulation models are extremely important and scientists are watching the changes on a large scale, he said.
The Atlantic Ocean, for example, accounts for about half of the Pacific Ocean, but research shows that the Atlantic absorbs almost as much carbon. This is because ocean circulation in the Atlantic discharges deeper waters than in the Pacific, which means that the effects of man-made carbon emissions can be detected more than a kilometer below the surface of the ocean. the ocean.
If ocean circulation slowed, some scientists speculated that the ocean could not absorb as much carbon. This could intensify global warming as additional carbon would remain in the atmosphere and not be absorbed by the ocean.
The data analyzed in the Science paper suggest a slowdown in traffic, Deutsch added, but as the study duration exceeds only 13 years, the cause is unclear and could to be natural and benign.
"We think this is more consistent with natural variability than with long-term changes right now," said Feely. "It remains to be seen."
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The Pacific Northwest may be particularly sensitive to increased carbon in the ocean.
"Here in the Pacific Northwest, ocean acidification is more intense than in other areas," says Jan Newton, a UW oceanographer who jointly runs the Washington Ocean Acidification Center. .
The waters of the Pacific Northwest – teeming with breathing lives that emit carbon dioxide – naturally contain more dissolved carbon than other seas, Newton said.
In the summer, along the Washington coast, upwelling, an oceanic model that is surfacing, presents waters rich in nutrients and CO2 and low oxygen, Newton said. Meanwhile, in the Strait of Puget, the tidal mix brings deep, carbon-rich water.
Humans are adding carbon to waters that are already naturally more corrosive.
"It may be noticeable," Newton said. "We are starting to see some of these effects faster than other places in the world."
Ocean acidification has already hindered the shellfish sector. A more acidified ocean can prevent oysters and other crustaceans from forming.
Research by UW has shown that CO2-rich water can affect the ability of some salmon to treat odors, which is essential for fish to avoid predators.
Newton added that the more corrosive waters reduced the success of krill breeding.
"Some organisms will be resilient and adapt, but it's a general stress" to have more carbon in the water, Newton said. "At some point, it becomes a limit and it's the part that, to a certain extent, is impossible to know. And that's the part we really need to take into account. "
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