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How much carbon does the ocean absorb? – World Economic Forum

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  • The oceans play a critical role in capturing CO2 from the atmosphere.
  • Around 25% of all CO2 emissions are absorbed by the ocean, making it one of the world’s largest ‘carbon sinks’.
  • However, new evidence suggests this figure could be even higher.

The oceans cover over 70% of the Earth’s surface and play a crucial role in taking up CO2 from the atmosphere.

Estimates suggest that around a quarter of CO2 emissions that human activity generates each year is absorbed by the oceans.

However, in our recent Nature Communications paper, we show that the ocean carbon “sink” could be even larger.

We find that the very surface of the ocean tends to be markedly cooler than the water at a few metres depth, resulting in a substantially larger net uptake than previously thought.

Our findings have implications for our accounting of the CO2 we are emitting – namely, where does the large fraction of CO2 that is taken up each year by “natural” sinks actually go?

Each year, the Earth’s surface takes up billions of tonnes of CO2 from the atmosphere. These natural carbon sinks – oceans, plants and soils – help to buffer the continued emissions from human activity.

The ocean absorbs CO2 from the atmosphere because, as the atmospheric concentration increases, more is dissolved in the surface water. This water may then mix down, or sink as it is cooled, into the deep sea where the absorbed CO2 can stay locked up for hundreds of years as it slowly moves through the deep interior ocean and back to the atmosphere.

But the oceans have not always been a carbon sink.

Before the industrial era, the ocean was actually a net source of CO2. However, the increasing atmospheric CO2 concentrations, driven by human-caused emissions are forcing the ocean to now absorb this gas.

While the ability of the ocean to capture and store carbon has helped to slow the accumulation of atmospheric CO2 – and, hence, the pace of global warming – it has come at a cost. Increasing CO2 in the ocean alters the chemistry of seawater – an effect known as ocean acidification – which has negative impacts on marine life.

New observations

Each year, the global carbon budget is assessed to track how well, or not, humanity is achieving any reductions in greenhouse gas emissions.

This assessment involves calculating sources and sinks of CO2 across the world and determining the change in atmospheric CO2 concentrations.

Estimating the ocean sink is clearly needed to complete this assessment, but its importance has a knock-on impact for other parts of the overall budget.

The huge variations in land cover, vegetation, terrain and their year-to-year variations mean that it is currently very difficult to measure the total global land sink accurately. Solving this issue is complex and complicated. However, it can be estimated indirectly.

Scientists can calculate the total human-caused emissions and observe how much of this CO2 stays in the atmosphere. The remainder must have been absorbed by either the land or the ocean. So a good estimate of the ocean sink also enables calculation of how much is being taken up by the vegetation on land. Put simply, the CO2 that goes missing that doesn’t go into the ocean, must go into the land.

Nonetheless, quantifying the carbon absorbed by the vast oceans – whilst they are less variable when compared to the land – is still a complex problem. It requires measurements and observations from a range of sources including ships, buoys and even satellites.

Thankfully, satellite measurements are now becoming much easier to access as European and international agreements have made these widely available to scientists.

Such satellites have many uses, including ocean weather forecasting, so they are well maintained. The situation is a little different for measuring how much CO2 seawater contains, as these measurements are collected by researchers and then voluntarily collated into the Surface Ocean CO2 Atlas (SOCAT).

These – along with the other observations – form a critical part of our ability to determine the oceanic sink. Each year more than a million new measurements are added to SOCAT; a herculean effort involving scientists throughout the world.

Oceanographers and chemists working together

While previous estimates put the ocean sink at around 2bn tonnes of CO2 per year, we find that it could be 0.8-0.9bn tonnes larger. Over the whole 27-year study period of 1992-2018, this means the global oceans have taken up 67bn tonnes of CO2 rather than 43bn.

This advance in knowledge resulted from us working closely with specialists in sea temperature, physical oceanography and satellites. They explained that satellite sensors measure the temperature at the very surface of the ocean and that vertical changes in temperature occur near the surface.

This means that the temperature at the very surface of the water – its “skin” – is slightly cooler than the water below. This is because the ocean is heated by the sun and must get rid of this heat by evaporation and radiation from its skin. We realised that this meant that the CO2 in the water will also change near the surface, as the solubility of CO2 in the water is highly temperature dependent.

Though the temperature difference is usually quite small, it is systematically in one direction over most of the world’s oceans, resulting in a larger amount of CO2 entering the water.

These temperature characteristics are well studied in oceanography and they teach this theory on undergraduate degree programmes, but no one had clarified its full impact on carbon.

Ironically, this issue had been partly highlighted by marine carbon researchers and published in the journal Nature in 1992, but all of this information had since been ignored.

Our earlier work focused just on 2010 – and now on 1992-2018 – and brings all of this cross-disciplinary knowledge together. Our new study shows that the results are consistent with an independent method for calculating how much carbon has entered the ocean.

Implications of a larger ocean carbon sink

A larger ocean sink could imply that CO2 emissions are larger than currently thought or that the land sink is smaller than we currently think.

The sink seems to be increasing with time, especially in the last 20 years, and we believe this is because atmospheric CO2 has continued to rise rapidly, dissolving more every year into the surface waters.

You can see this in the charts below, which show the ocean-atmosphere exchange of CO2 over the study period for the whole world (top) and the northern and southern hemispheres (bottom). The coloured lines show different estimates, while the thick black line shows the average.

Following convention, the uptake of CO2 into the ocean is shown as negative, so descending lines indicate that the ocean is absorbing more CO2.

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Charts show atmosphere-ocean CO2 exchange for a) the globe, and b) for northern and southern hemispheres for 1992-2018.

Image: Carbon Brief

Our findings may also mean that the exchanges of carbon between the ocean and land – including those from large rivers like the Amazon, and that we currently consider to be relatively similar from year to year – are in fact more variable.

The answer will be difficult to determine, but is likely to need a cross-disciplinary approach involving modelling, satellite and ship-based scientists. Accounting for these new results will also likely involve some revision to the way in which we quantify global carbon budgets.

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Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

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More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.

That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.

“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”

The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.

Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.

Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.

Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.

Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.

Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.

“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”

The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.

North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.

Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”

Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.

Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.

For Dello, the “fingerprints of climate change” were clear.

“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”

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Follow AP’s climate coverage at https://apnews.com/hub/climate

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Follow Seth Borenstein on Twitter at @borenbears

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Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

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‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it “Big Sam.”

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didn’t die alone.

“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”

“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”

“It contains about 100 to 300 bones per square metre,” she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.

“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.

“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.

“It’s pretty exciting.”

This report by The Canadian Press was first published Sept. 25, 2024.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

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