WaPo: By 2030, half the world’s oceans could be reeling from climate change, scientists say

by Chelsea Harvey, The Washington Post,March 7, 2017 

A diver checks the bleached coral at Heron Island on the Great Barrier Reef. (XL Catlin Seaview Survey/Agence France-Presse)

More than half the world’s oceans could suffer multiple symptoms of climate change over the next 15 years, including rising temperatures, acidification, lower oxygen levels and decreasing food supplies, new research suggests. By mid-century, without significant efforts to reduce warming, more than 80% could be ailing — and the fragile Arctic, already among the most rapidly warming parts of the planet, may be one of the regions most severely hit.

The study, published Tuesday in the journal Nature Communications uses computer models to examine how oceans would fare over the next century under a business-as-usual trajectory and a more moderate scenario in which the mitigation efforts promised under the Paris Agreement come into effect. In both scenarios, large swaths of the ocean will be altered by climate change.

Nearly all of the open sea is acidifying because of greenhouse gas emissions. But the researchers found that cutting greenhouse gas emissions could significantly delay future changes, giving marine organisms more time to migrate or adapt.

“Things that live in the ocean are used to regular variability in their environments,” said lead study author Stephanie Henson, a scientist at the National Oceanography Center at the University of Southampton in Britain. “It gets warm in the summer and it gets cold in the winter, and species survive that kind of range in temperature or other conditions perfectly well.”

But she noted a warming climate could eventually cause changes in the ocean that have never happened before — hotter temperatures, lower pH or less oxygen than have ever naturally occurred. When this happens, some organisms may no longer be able to tolerate the changed conditions and will be forced to migrate, evolve as a species or face possible extinction.

There’s a large degree of uncertainty in the scientific community about how organisms will react. But there’s evidence to suggest major challenges ahead. Mass coral bleaching events in the past few years have been largely attributed to unusually warm water temperatures. Large-scale coral death on the Great Barrier Reef last year is thought to be strongly linked to climate change.

“So we wanted to know when will climate change actually push the system outside the range of natural variability that organisms are used to,” Henson said.

The researchers focused on four specific climate-influenced “drivers,” of marine ecosystems: temperature, pH, oxygen levels and “primary production,” or how much food is available to a community.

Some parts of the ocean are already experiencing certain climate-driven changes beyond the limits of their natural conditions. The researchers note in the paper that 99% of the open ocean is experiencing a climate-driven change in pH, or ocean acidification. The subtropics and the Arctic are also experiencing sea surface temperatures beyond their natural ranges. And these changes will only continue to spread.

Under a business-as-usual climate scenario, the researchers found an alarming portion of the ocean will be affected by changes in multiple drivers at once. By 2030, they projected, 55% of the world’s oceans will experience changes in more than one of these factors — temperature and pH, most commonly — beyond the range of natural variability. By 2050, this number rises to 86%.

The researchers focused on areas where multiple changes are occurring at once. “We think that multiple different factors occurring at the same time probably have different responses in the marine environment than just one factor at a time,” Henson said. “So, for example, the combination of warming and ocean acidification may be even more detrimental than just one of those factors alone.”

The projections suggest climate mitigation can stall these effects — at least for a little while. Under the moderate climate scenario, the researchers found, 34% of the ocean will be affected by changes in multiple drivers, and 69% by 2050. In general, they concluded that climate mitigation can delay the onset of climate-influenced changes by about 20 years.

“Mitigation doesn’t stop the emergence of multiple different stressors in the ocean, but it does slow things down quite significantly,” Henson noted.

This delay could buy time for organisms to move or adapt to their surroundings, the researchers said. Fast-moving fish may be able to migrate to more hospitable waters, while organisms with speedy generation times, such as plankton, may be able to quickly evolve to their changing environments.

On the other hand, organisms in places with very stable environments and low natural variability in their conditions — the subtropics, for instance — may be especially vulnerable to future, climate-driven changes. Certain parts of the world are also likely to see more rapid changes than others. Their projections suggest that the Arctic will be a particular “hotspot” for changes in temperature, pH and oxygen content.

Scientists are still struggling to figure out which organisms are mostly likely to adapt or move — and which are most likely to die. But they do know there are bound to be winners and losers and that some changes to marine communities are likely to be long-lasting, if not permanent — long after greenhouse gas emissions have been curbed.

https://www.washingtonpost.com/news/energy-environment/wp/2017/03/07/by-2030-half-the-worlds-oceans-could-be-reeling-from-climate-change-scientists-say/

NYT: Our Deadened, Carbon-Soaked Seas

                  Credit Alec Doherty       

by Richard W. Spinrad and Ian Boyd, The New York Times, October 15, 2015

Ocean and coastal waters around the world are beginning to tell a disturbing story. The seas, like a sponge, are absorbing increasing amounts of carbon dioxide from the atmosphere, so much so that the chemical balance of our oceans and coastal waters is changing and a growing threat to marine ecosystems. Over the past 200 years, the world’s seas have absorbed more than 150 billion metric tons of carbon from human activities. Currently, that’s a worldwide average of 15 pounds per person a week, enough to fill a coal train long enough to encircle the equator 13 times every year.

 

We can’t see this massive amount of carbon dioxide that’s going into the ocean, but it dissolves in seawater as carbonic acid, changing the water’s chemistry at a rate faster than seen for millions of years. Known as ocean acidification, this process makes it difficult for shellfish, corals and other marine organisms to grow, reproduce and build their shells and skeletons.

About 10 years ago, ocean acidification nearly collapsed the annual $117 million West Coast shellfish industry, which supports more than 3,000 jobs. Ocean currents pushed acidified water into coastal areas, making it difficult for baby oysters to use their limited energy to build protective shells. In effect, the crop was nearly destroyed.

 

Pteropods, sometimes called sea butterflies, are a vital food source for Salmon and Herring. Left, a pteropod that has lived in normal waters in a laboratory for six days, and, on the right, a pteropod showing the effects of living in acidified water for the same time period. The white lines indicate shell dissolution, showing why ocean acidification is often called "osteoporosis of the sea." Credit National Oceanic and Atmospheric Administration 

Human health, too, is a major concern. In the laboratory, many harmful algal species produce more toxins and bloom faster in acidified waters. A similar response in the wild could harm people eating contaminated shellfish and sicken, even kill, fish and marine mammals such as sea lions.

 

Increasing acidity is hitting our waters along with other stressors. The ocean is warming; in many places the oxygen critical to marine life is decreasing; pollution from plastics and other materials is pervasive; and in general we overexploit the resources of the ocean. Each stressor is a problem, but all of them affecting the oceans at one time is cause for great concern. For both the developing and developed world, the implications for food security, economies at all levels, and vital goods and services are immense.

 

This year, the first nationwide study showing the vulnerability of the $1 billion U.S. shellfish industry to ocean acidification revealed a considerable list of at-risk areas. In addition to the Pacific Northwest, these areas include Long Island Sound, Narragansett Bay, Chesapeake Bay, the Gulf of Mexico, and areas off Maine and Massachusetts. Already at risk are Alaska’s fisheries, which account for nearly 60% of the United States commercial fish catch and support more than 100,000 jobs.

Ocean acidification is weakening coral structures in the Caribbean and in cold-water coral reefs found in the deep waters off Scotland and Norway. In the past three decades, the number of living corals covering the Great Barrier Reef has been cut in half, reducing critical habitat for fish and the resilience of the entire reef system. Dramatic change is also apparent in the Arctic, where the frigid waters can hold so much carbon dioxide that nearby shelled creatures can dissolve in the corrosive conditions, affecting food sources for indigenous people, fish, birds and marine mammals. Clear pictures of the magnitude of changes in such remote ocean regions are sparse. To better understand these and other hotspots, more regions must be studied.

 

We cannot yet predict exactly how ocean acidification will affect connections among the world’s many different marine organisms, but we do know the consequences will be profound. Research already points to the unnatural behavior of coral clownfish in an acidified environment. These fish wander farther from their natural protection, making them more vulnerable to predators. We have yet to learn how salmon and other commercially important fish will adapt as acidification erodes their food supply, especially since some of the most vulnerable species are the small, simple life forms that juvenile salmon and other fish depend on. There may be cascading impacts that we don’t yet fully understand. Acidification won’t make seawater dangerous for swimming, but it will upset the balance among the multitudes of microscopic life found in every drop of seawater. Such changes will almost certainly affect seafood supplies and the ocean’s ability to store pollutants, including future carbon emissions.

 

To understand where the challenges lie, we need better ocean-measuring capability, linked with improved modeling of marine ecological systems. Smart investments in monitoring and observing are critical to building resilience and hedging risks that can directly affect economies at all levels. There is urgency to such investments. The U.S. National Oceanic and Atmospheric Administration conducts round-the-clock monitoring of global CO2. The rate of increase has never been higher than during the past three years, accelerating the ocean acidification process.

 

Both the United States and Britain recognize that rising CO2 and the production of other greenhouse gases have widespread consequences and have called for strong action to reduce carbon emissions. We are pleased that representatives of our two nations help lead the pioneering Global Ocean Acidification Observing Network, a collaboration of scientists from 30 countries. This network is based on the premise that we can’t manage what we don’t measure. It’s designed to provide the basis for robust forecasting by integrating existing observations from unmanned vehicles, research vessels, volunteer observing ships and many more assets.

 

The new network will build on the success of the American and British teams that recently came in first and second in the Wendy Schmidt Ocean Health XPRIZE by developing affordable, accurate sensor technology. Such technology will help coastal countries around the world obtain the environmental information required to underpin sound policy and build community and global resilience. Already oyster hatcheries on the U.S. West Coast are working with scientists to monitor water quality and adapt to ocean acidification so baby oysters can survive. And while ocean acidification is a global concern, inroads are occurring at the local scale, encouraging control, for example, of nutrient pollution that can exacerbate acidification.

 

When it comes to the health of the sea, we are all stakeholders. The ocean is a harbinger of our own well-being and the resilience and economic viability of our planet. We ignore the risks of ocean acidification at our own peril, and that of future generations.

 

Richard W. Spinrad is the chief scientist of the U.S. National Oceanic and Atmospheric Administration. Ian Boyd is the chief scientific adviser to the British government’s Department of Environment, Food and Rural Affairs.       

http://www.nytimes.com/2015/10/16/opinion/our-deadened-carbon-soaked-seas.html

Chance to rescue the world’s oceans from climate change is drifting away

Acehnese fishers are among the quarter of the world’s population who live on the coast, and for whom climate-driven changes to the oceans would make life much harder. Hotli Simanjuntak/EPA/AAP Image

by Ove Hoegh-Guldberg, Director, Global Change Institute, The University of Queensland, The Conversation, July 2, 2105

Until recently, you might be forgiven for thinking that the oceans were a trivial component of Earth’s climate system, and that the consequences of change were minimal. After all, only 5% of papers published on climate change involve ocean systems. The Intergovernmental Panel on Climate Change (IPCC), which evaluates the peer-reviewed scientific literature, did not devote a regional chapter to the ocean until its most recent major report.

Yet the ocean system could not be more important: it regulates the global temperature and atmosphere, feeds 3 billion people, and largely determines our weather. The ocean also has lots of “inertia” – which means that getting the ocean to change takes a lot of energy, but once it begins to change, slowing it down becomes more or less impossible.

A paper published today in Science (on which I am one of the authors) has issued a warning that our window of opportunity to save the oceans from major changes is in danger of slamming shut, bringing with it the risk that we will encounter planetary-scale tipping points in the behaviour of the climate. Building on the IPCC’s extensive assessment last year of the effects of climate change on the oceans, my co-authors and I have compiled the latest evidence and projections about the ocean under rapid human-driven climate change.

The news is not good. Failure to act on climate change will see warmer and more stagnant oceans, with declining oxygen levels and productivity in some regions, and the removal or modification of ecosystems in other areas. Fisheries and national economies are in the cross hairs in many regions. Rising seas and intensifying storms, plus a loss of critical coastal features, will make life on the shores of a rapidly changing ocean dangerously different to today.

The risks currently being experienced across the planet. Most, if not all, are set to increase. Gattuso et al.

Click to enlarge

A lot hinges on whether we can meet the globally agreed 2 C “warming guardrail,” but there are fears that this is impossible within current economic strategies, and that even this target is unsafe.

It would be fine to state this if we had a safe alternative, but we don’t. Consequently, the bar for the end-of-year Paris climate summit is set much higher than many understand. As I’ll explain below, we need a global deal that reduces global emissions to zero over the next 20 years, or else we will see momentous changes.

Calls to action

Thankfully, world leaders are beginning to wake up to the challenge facing our oceans. US Secretary of State John Kerry and Prince Albert II of Monaco, are among those who have spoken out against what many see as impending chaos.

The latest is Pope Francis, who became the first pontiff to warn of ocean warming, acidification and sea-level rise, pointing out in his recent encyclical that “a quarter of the world’s population lives on the coast or nearby, and … the majority of our megacities are situated in coastal areas.”

For the first time, the Vatican is fighting for the ocean. Ove Hoegh-Guldberg, Global Change Institute, University of Queensland

Our research adds to the already mounting evidence that these leaders are right when they say we need to act decisively on fossil fuel emissions and other drivers of climate change.

One of the most stunning conclusions from the IPCC’s report is the statement that “the current rate and magnitude of ocean acidification are at least 10 times faster than any event within the last 65 million years.” Given that periods of rapid acidification over tens of thousands of years – slow by our current human-driven standard – resulted in mass extinction and ecological collapse, this alone should be reason to act.

In a few regions, such as the North Sea, temporary increases in fisheries production are being reported, as the ice retreats, seas warm, and productivity increases. But these benefits are few and far between, and are likely to disappear over time as the ocean warms and acidifies further.

Coral reefs perhaps provide the perfect parable for the Pope’s encyclical. Everyone appreciates their beauty and value, but few may be aware of the crucial role that they play in terms of protecting coastlines, and supporting fisheries and other industries. They generate hundreds of billions of dollars each year and support some 500 million mostly poor people worldwide. Our report highlights the extreme sensitivity of these ecosystems to ocean warming and acidification.

Climate-driven changes in the oceans pose risks to organisms, ecosystems, people and industry. Gattuso et al.

Click to enlarge

Work to do at the Paris summit

As we progress down the road to Paris, paved with skeletons of these important organisms, there is little doubt about the amount of work that needs to be done in Paris. Analysis of the world’s “carbon budget” (see here and here suggest that we can emit about another 500–800 billion tonnes (gigatonnes) of carbon dioxide before we push global temperatures beyond 2 C above the pre-industrial average. This gives us about 20 years before net global emissions have to fall to zero – a tall order indeed.

There is hope. The recent US–China climate deal is one reason to be optimistic that negotiations in Paris will be smoother than at the Copenhagen climate talks in 2009. But I wonder whether leaders are aware of the true scale of the work that needs to be done to avoid catastrophe. Perhaps the fact that China this week made clear the strength of its new climate commitments is evidence of this.

Yet here is a sobering calculation: imagine that the rest of the world falls into line with the US and Chinese climate targets. How much of the world’s budget would we burn?

The answer would be that the world had emitted 1,400 gigatonnes of CO₂, or 175–280% of our remaining budget, dragging average global warming to 3C and beyond (see the orange line on the graph below). This would be disastrous for us and our children, and many of the benefits of our oceans (coral reefs, fisheries, coastal living) would be transformed beyond recognition.

The relationship between cumulative carbon dioxide emissions and future average global temperatures. IPCC

Click to enlarge

An ethical response

Mention of “us and our children” brings us back to Pope Francis and the importance of not reducing everything to a dollar value. Yet even in pure economic terms, given that the IPCC calculates that keeping atmospheric CO₂ below about 450 parts per million (which would give us a good chance of staying within the 2 C guardrail) would cost just 0.06% of global consumption growth per year, one is left wondering why we are not jumping right in and solving this problem.

Pope Francis made an important observation:

In a word, businesses profit by calculating and paying only a fraction of the costs involved. Yet only when “the economic and social costs of using up shared environmental resources are recognized with transparency and fully borne by those who incur them, not by other peoples or future generations,” can those actions be considered ethical.

Once can only hope the leaders heading to Paris will heed his words and drive their efforts in a new direction.

https://theconversation.com/new-report-the-chance-to-rescue-the-worlds-oceans-from-climate-change-is-drifting-away-43257

"We're f'd!": ocean acidification

Dear Readers, I am going to introduce a sort of series. From time to time, I'm going to post various items that show just how screwed we really are.  The series takes its name from Dr. Jason Box's famous tweet:

http://www.salon.com/2014/08/06/climate_scientist_drops_the_f_bomb_after_startling_arctic_discovery/



http://www.epa.gov/climatechange/images/science/CalciumCarbonateMap-large.jpg

Increase in shellfish deaths causes 'full-scale panic' for B.C. industry

 

B.C.’s shellfish industry is struggling for survival as it deals with rising ocean temperature and acidification. Photograph by: Gerry Kahrmann, PROVINCE

by BY GLENDA LUYMES, THE PROVINCE, February 17, 2015

   

Despite insatiable demand, many are concerned B.C.’s once-thriving shellfish industry could be sinking.

“I’d say it’s full-scale panic mode (for scallop farmers),” said Rob Saunders, CEO of Qualicum Beach-based Island Scallops.

The company has seen its scallop death rates rise to nearly 95% since 2010, leading to millions of dollars in losses. Ocean acidification — a worldwide problem — is likely to blame.

Saunders said the company’s hatcheries, which produce scallop, oyster, prawn and sea urchin “seeds,” have also had trouble with increased deaths. In order to grow, the B.C. industry must double its seed production.

“Everyone is desperately trying to understand what’s going on and what can be done,” he said.

Other B.C. shellfish growers, like Denman Island oyster farmers Greg Wood and his wife Hollie, have found themselves “going year by year to see if we can make it.”

Wood blames oyster mortality rates on rising ocean temperatures, which cause more parasites and bacteria to grow.

“The problems are extreme,” he said. “We’re being attacked from all angles.”

The possibility of a coal mine a few kilometres from Baynes Sound, where 50% of B.C.’s shellfish are grown, is a major concern.

While each type of shellfish is different in its ability to tolerate changing ocean conditions, they all depend on a clean environment, said Roberta Stevenson, executive director of the B.C. Shellfish Grower’s Association.

“Ocean warming, urban run-off, acidification — it all has an impact,” she said.

Production on B.C.’s coast has dropped 12% since 2003, according to the association.

Red tape has also been a problem for the industry, which is regulated by Fisheries and Oceans Canada, but receives business licensing through the provincial Ministry of Agriculture and land-use licenses through the Ministry of Forests, Lands and Natural Resource Operations.

“We’d like to see some of the processes streamlined and have one agency that oversees all aquaculture,” said Stevenson.

One thing that is not a problem, however, is demand.

Considered a clean, sustainable industry by many, local shellfish farmers have more customers than they can satisfy.

Hollie Wood Oysters sells its oysters within 160 kilometres, supplying many Vancouver Island chefs, said Wood.

“People know us as a local brand, and we’ve really been able to work with the local food movement.”

Wood described shellfish farming like gardening: “We put the seeds out and then raise them. It’s like an ocean garden.” Shellfish don’t require feed and eat naturally-occurring phytoplankton. A critical component of a healthy marine environment, they essentially filter the ocean water.

But the industry has met with criticism for its impact on shorelines and beaches.

“We’ve done beach cleanups for about 10 years now, and each time we haul away three to five tonnes of debris, mostly plastics,” said Shelley McKeachie, co-chair of the Association of Denman Island Marine Stewards.

She recounts finding a beach covered in “snow” — tiny white Styrofoam pellets from the shellfish rafts — after a storm.

“The industry is riddled with environmental issues that haven’t been addressed,” said McKeachie, insisting her group’s opposition is not borne out of NIMBY-ism (the “Not in my Backyard” attitude), but rather from a concern for the beaches and water.

Those concerns may become irrelevant if the industry can’t stay afloat.

UBC marine biologist Dr. Curtis Suttle has been studying the “large mortality events” affecting B.C. farmed shellfish.

“We don’t have a great understanding of what is going on,” he said.

Ocean acidity is a likely factor, with intrusions of very acidic water from deep below the surface making it difficult for some species to form adequate shells.

“The problem is probably not just acidity by itself,” said Suttle. “Stressful conditions make the shellfish more susceptible to disease, and different water masses come in with different pathogens.”

Suttle and a fellow scientist from the University of Victoria have applied to the federal government for funding to put together an international team to examine the problem.

“We want to see if there are particular scallops that are more resistant,” he said. “We can’t change ocean circulation, but we hope there’s a way to have a sustainable shellfish industry here.”

For Saunders, it’s all about finding a scallop “survivor.”

“We’re hoping we can identify and breed something that is resistant. Something that could be the foundation for the industry again.”

http://www.theprovince.com/technology/Increase+shellfish+deaths+causes+full+scale+panic+industry/10817998/story.html

The biggest extinction ever known on Earth resulted from oceans turned acid by CO2, the main gas driving human-caused climate change today

by Tim Radford, Climate News Network, April 16, 2015

LONDON − Scientists have identified the lethal agency that caused the single most catastrophic event in the history of life on Earth. The mass extinction at the boundary of the Permian and Triassic eras 252 million years ago was caused by the acidification of the world’s oceans, as a consequence of an increase in atmospheric carbon dioxide.

The Permian Extinction – sometimes called “the Great Dying” – seemed to all but obliterate life in the oceans, and perhaps on land. More than 90% of all species disappeared, more than 80% of all genera, and more than 50% of all marine families were extinguished in one prolonged calamity.

All life on Earth today has descended from the few survivors of this far-off episode. Palaeontologists, geologists, climate scientists and astronomers have all speculated on the probable cause. The latest and most confident analysis is based on a new study of ancient marine sediments and delivers obvious parallels with processes that are – for different reasons − occurring again today.

Matthew Clarkson of the University of Edinburgh in Scotland (but now at the University of Otago in New Zealand) and colleagues report in the journal Science that they examined limestone from the United Arab Emirates and found, in the isotope ratios of the element boron, evidence of ocean acidity in carbonate rocks that were laid down as sediment at the bottom of the ocean 250 million years ago. A change in the isotope ratios, they calculated, would have indicated a significant shift in seawater chemistry.

Over the last 40 years, researchers have introduced a whole suite of plausible triggers for the Permian extinction, but at last one team had clear evidence of increased atmospheric carbon, probably from a prolonged and convulsive series of volcanic eruptions that gave rise to vast, ancient geological formations now known as the Siberian Traps.

“Scientists have long suspected that an ocean acidification event occurred during the greatest mass extinction of all time, but direct evidence has been lacking until now,” said Dr Clarkson. “This is a worrying finding, considering that we can already see an increase in ocean acidity today that is the result of human carbon emissions.”

There has been recent evidence that this present change in the pH of ocean waters (pH is a measure of its acidity) as a consequence of fossil fuel combustion in the last two centuries has already disturbed the behaviour of some fish species, threatened to affect oyster fisheries and coral reefs, and even to alter whole ocean ecosystems.

The changes in the Permian were not sudden: ecosystems already seriously under stress because of lack of oxygen or rising temperatures were then dramatically affected by discharges of carbon dioxide that were probably much greater than all the modern world’s existing fossil fuel reserves could deliver. As the oceans became more acidic, many species were extinguished forever: among them the trilobites.

The whole chain of events took 60,000 years. Humans have been burning fossil fuels for only 200 years, but, the researchers point out, in the Permian crisis, carbon was probably being released into the atmosphere at the rate of about 2.4 billion tons a year. Right now, humans are estimated to be releasing carbon from fossil fuels at the rate of 10 billion tons a year. 

Ocean sediment reveals that release of carbon stored deep in the sea is linked to the rise in atmospheric CO2 that caused the world to warm

by Tim Radford, Climate News Network, February 13, 2015

LONDON − Scientists believe they may have cracked the mystery of the end of the last ice age. The temperatures suddenly soared, and the glaciers went into retreat, because the deep southern ocean released huge quantities of carbon dioxide.

And the convincing answers have been delivered by analysis of the composition of calcium carbonate shells of ancient marine organisms.

The link between human burning of fossil fuels and the steady rise in atmospheric carbon dioxide levels was proposed more than a century ago and firmly established in the last 30 years.

But the ups and downs of planetary temperatures before the emergence of human civilisation are harder to explain. Fossil evidence suggests a link with carbon dioxide levels, but not necessarily a cause.

Bygone climates

Now paleoceanographer Miguel Martínez-Botí, from the University of Southampton, UK, and ocean and climate change researcher Gianluca Marino, from the Australian National University, report in Nature that they found their evidence in sediment cores – in effect, annual records of bygone climates – rich in the shells of tiny foraminifera called Globigerina bulloides.

This is a species that flourishes in conditions of high nutrients, acting as a kind of biological pump, gulping carbon from the atmosphere.

They found that high concentrations of carbon dioxide dissolved in surface waters of the southern Atlantic Ocean and the eastern equatorial Pacific coincided with rises in atmospheric CO2 at the end of the last ice age.

The implication is that these regions were the source of the carbon dioxide to the atmosphere.

At their coldest, during the ice ages, carbon dioxide levels fell to 185 parts per million. During the interglacials, when the world warmed and lions and hyenas roamed the plains of Europe, the carbon dioxide levels rose to 280 ppm.

Right now, thanks to human activity, CO2 levels are rising ominously towards 400 ppm.

The oceans are home to about 60 times more carbon than the atmosphere and can, it seems, surrender it rapidly.

“The magnitude and rapidity of the swings in atmospheric CO2 across the ice age cycles suggest that changes in ocean carbon storage are important drivers of natural atmospheric CO2 variations,” Dr Martínez-Botí says.

“Our findings support the theory that a series of processes operating in the southernmost sector of the Atlantic, Pacific and Indian oceans, a region known as the Southern Ocean, changed the amount of carbon in the deep sea.

Into the abyss

“While a reduction in communication between the deep sea and the atmosphere in this region potentially locks carbon away from the atmosphere into the abyss during ice ages, the opposite occurs during warm interglacial periods.”

To arrive at their conclusion, the scientists had to analyse subtle evidence from the isotopic composition of the carbonate shells, and then use mathematical techniques to reconstruct a story of a great, faraway sigh of carbon dioxide from the ocean to the atmosphere.

The finding, based on calculated probabilities, is incomplete as there may have been other forces also at play.

Gavin Foster, associate professor in isotope geochemistry at the University of Southampton, says: “While our results support a primary role for the Southern Ocean processes in these natural cycles, we don’t yet know the full story. Other processes operating in other parts of the ocean, such as the north Pacific, may have an additional role to play.” 

Carbon stored deep in Antarctic waters ended the last ice age

by Miguel Martinez-Boti, University of Southampton and Gianluca Marino, Australian National University, The Conversation, February 12, 2015

It’s well known that carbon in the atmosphere is causing global warming. What is less well known, outside of scientific circles at least, is the role oceans have to play in this. Our seas contain 60 times more carbon than the atmosphere, and they can release it at sufficiently rapid rates to cause dramatic changes in the climate. In fact, as we describe in research published in Nature, CO₂ released by the oceans brought about the end of the last ice age.

More than 50 million cubic kilometres of ice once covered North America and Scandinavia. It melted away between approximately 19,000 and 10,000 years ago, releasing enough water to raise the sea level by about 130 metres. This came after CO₂ concentrations increased by approximately 50%, from 180 to 280 parts per million between the last ice age and the current interglacial period. To explain such a pronounced increase, we have to look at the ocean.

Scientists have thought for a long time that the southern sectors of the Atlantic, Indian and Pacific Oceans, a region known as the Southern Ocean, may be key to explaining the increase in atmospheric CO₂.

Large volumes of deep water loaded with carbon come to the surface in this area. However, the low concentration of certain nutrients (for example iron) in surface waters limits the metabolism of planktonic organisms, which cannot fully consume all the carbon brought to the surface ocean, resulting in CO₂ being “outgassed” to the atmosphere.

We wanted to assess if the ocean contributed to the atmospheric CO₂ increase during the last deglaciation, so it made sense to look at areas that are important today for the ocean-atmosphere exchange of carbon: the Atlantic Sector of the Southern Ocean and the Eastern Equatorial Pacific, another area where deep, cold water rises to the surface.

But how can we then go back in time and check if these areas were a source of CO₂ in the atmosphere? The answer is buried a few thousand meters below the surface of the oceans.

Deep-sea drilling for sediment samples. William Crawford, IODP/TAMU, CC BY-NC-SA

Research vessels such as the Joides Resolution are capable of drilling the sea floor to recover long sequences of sediments in which the history of the oceans is recorded. The sediments contain, among other things, fossils of tiny organisms that once lived in the upper ocean, called foraminifera. These creatures build chalky shells, and the waters they live in influence their chemical composition.

After death, the shells sink to the bottom of the oceans, where they accumulate. We analysed the sediment cores and looked for the isotopic composition of the element boron present in shells that lived during particular times of interest. Boron tells us pH levels of the waters, which in turn tells us about carbon levels: a high concentration of CO₂ in the waters will make them more acidic (lower pH), and vice versa.

We found a link. When the glaciers of the last ice age were melting, and the atmospheric CO₂ was increasing, the surface waters of the Southern Ocean and the Eastern Equatorial Pacific were also more acidic. This signalled an increased concentration of CO₂ – much higher than those in the atmosphere.

This is the key finding of our research: the ocean was a source of CO₂ to the atmosphere during key intervals of the last deglaciation, which explains the large increase in CO₂ concentrations.

Where did this carbon come from?

It’s the next obvious question. Previous research has found that the last ice age saw much less carbon exchanged between ocean and atmosphere than we see today, mostly because the Southern Ocean was intensely stratified at the time and deep waters rarely made it to the surface. Nutrients and CO₂ were accumulating in the deep Southern Ocean, due to the decay of the organic matter that was being produced in the surface ocean and transported to the abyss.

Microscopic shells like this can reveal oceanic acidity. Mariana T. Horigome, Autonomous University of Barcelona, Author provided

During the deglaciation, the effective communication between deep and upper ocean was re-established, and this carbon “reservoir” was leaked to the atmosphere.

Since the beginning of the industrial revolution the oceans have absorbed an estimated 155 billion tonnes of carbon, about 30% of the total human emissions. The present atmospheric CO₂ concentrations, approximately 400 parts per million, have not been seen on Earth since the Pliocene, around 3 million years ago, and the rate of increase is unprecedented in the period of on-off glaciers we have had since.

Humanity is performing a large scale experiment with the Earth, and the consequences are already being seen in the form of increased atmospheric and oceanic temperatures, raising sea levels and ocean acidification, to name a few. How the oceanic uptake of CO₂ is going to operate in the future remains unknown, but studies like ours advance our understanding of how the ocean works to store and release carbon on timescales of millennia and that therefore are way beyond the reach of the instrumental record.


This article was originally published on The Conversation. Read the original article.

Irony Alert! Ken Cuccinelli’s New Business Will Not Survive Climate Change

by Joe Romm, Climate Progress, January 6, 2015

What’s the next step for a science-denying former politician? Launch a new business venture that will be utterly destroyed by human-caused climate in the coming decades. And if you wanted to pick a business venture that would be the most vulnerable to climate change, you could hardly do better then Ken Cuccinelli’s new oyster farm on super-low-lying Tangier Island, Virginia.

You remember Ken Cuccinelli. As Virginia Attorney General, he infamously launched a (losing) witch hunt against leading climatologist Dr. Michael Mann. Then, in the tight Virginia gubernatorial race of 2013, his climate science denial became a focus, and he lost to pro-science candidate Terry McAuliffe.

What did he do next? On Sunday, the Washington Post wrote a huge piece discussing “Ken Cuccinelli’s post-politics endeavor: oyster farming.” Amazingly, the Post managed to write a 1,600-word puff piece on this subject without ever mentioning climate change, the threat ocean acidification poses to oysters, or sea level rise.

“The outspoken conservative now seems focused on creating a new source of sustainable jobs for people on Tangier,” the Post’s story reads.

Tangier Island in the Chesapeake Bay

CREDIT: AP PHOTO/STEVE HELBER

Sadly, there are no sustainable jobs on Tangier. The Post notes that the island is home to about 700 residents, since “only 83 acres of the island high enough for human habitation,” but the Post has nothing whatsoever to say about the island’s inescapable future — even though for every other major news outlet, near-term inundation is the defining feature of the island.

In the Associated Press’s AP images, nearly half the photos that show up when you search for “Tangier Island” are titled simply, “Disappearing Island,” with captions noting how the island is “especially vulnerable to climate change.” Most other news articles on Tangier Island in recent years are about how rapidly it is losing land to the combination of subsidence and sea level rise. Case in point: the Virginian Pilot’s 2012 piece, titled “Residents of drowning Tangier Island look for lifeline.”

The Chesapeake Bay magazine’s piece, “That Sinking Feeling,” explains Tangier islands “will likely be inundated if sea level rises one meter (3.28 feet) or less,” which is the middle of current projections. They link to National Geographic’s interactive map at www.chesapeakeadaptation.org, which allows you to see the future of the doomed islands in the Bay. Business Insider had a piece in September headlined “The Twilight of Tangier: What It’s Like To Live On An Island That’s Disappearing Because Of Global Warming,” which notes the island is “only 4 feet or so above sea level at its highest point” and suggests it’ll be almost entirely submerged in 50 years.

Heck, even Fox News ran an extended AP story in 2013 that explains at length how “this island is disappearing,” and how global warming is accelerating the process: “Climate change is simply accelerating what they say will be increasing flooding along the bay and the foreseeable demise of Tangier.”

But hey, why should the Washington Post spoil a great human interest story about Ken Cuccinelli by mentioning that the island he’s putting his new business on is rapidly disappearing — and that the policies of climate denial and inaction by Cuccinelli and his buddies have sped up its death? No need to mention that in 2012, a Virginia lawmaker called sea level rise a “left wing term,” and removed it from a state report on coastal flooding.

The Post’s story seeks an uplifting spin, claiming that “for a figure who has seemed to attract controversy throughout his career in Virginia politics, Cuccinelli has found his way into an enterprise that isn’t the slightest bit controversial.” Not the slightest bit controversial? Certainly it is the slightest bit ironic.

The Post seems to have stumbled over the idea of “sustainable.” The fact is oyster farming is environmentally very sustainable and worthwhile, as the Post notes:

The Chesapeake Bay Foundation actively supports oyster farming. According to Tommy Leggett, an oyster restoration and fisheries scientist for the foundation, more oyster farming would mean a healthier bay.

“It’s a very sustainable and green business,” Leggett said, listing some of the environmental benefits of oyster farming. Oysters and their reefs provide a habitat for many other species, he said, and at certain water temperatures, adult oysters can filter up to 50 gallons of water per day.

I spoke to Leggett. He meant “environmentally sustainable.” He was speaking in terms of the environmental benefit to the Chesapeake, not whether the business itself was sustainable given climate change.

Ocean acidification driven by carbon pollution has already proven to be a major threat to the West Coast oyster industry, as was clear from the “The Great Oyster Crash” of 2007, in which “oyster seed (larvae) off the coast of Oregon and Washington began dying by the millions.” It turns out that rapidly acidifying coastal waters make it difficult for larvae by to build the shells needed for survival.

The Washington Post itself reported on this oyster crash and the growing threat from acidification in a July piece, “Marine industries at risk on both coasts as oceans acidify.” The Post noted:

On the East Coast, instead of upwelling, acidification is a result of nutrification — adding nutrients like agricultural waste, fertilizers and waste water treatment facilities. The Chesapeake Bay, which receives runoff from one of the most densely populated watersheds in the United States, is acidifying three times faster than the rest of the world’s oceans.

That July Post story explained that “the last time the oceans changed so dramatically, about 59 million years ago, during a geologic time known as the Paleocene-Eocene Thermal Maximum, the rate of change was 10 times slower than is occurring today.” Worth noting is that a 2010 Nature Geoscience study pointed out that the PETM saw a mass extinction of marine species occurred. As a leading climatologist pointed out that year, “when CO2 levels in the atmosphere reach about 500 parts per million, you put calcification out of business in the oceans.”

We’re currently at 400 ppm, rising at a rate of more than 2 ppm a year (a rate which itself is speeding up). The good news is that so far carbon-pollution-driven acidification does not appear to be harming the oyster industry in the Chesapeake Bay, according to Leggett who is also an oyster fisherman. But again, in a 1,600-word piece about a leading climate denier co-founding an oyster farm, you’d think it deserves at least a passing mention.

Bottom Line: It may be newsworthy that prominent climate science denier Ken Cuccinelli has started a new business venture on Tangier Island that is “environmentally sustainable.” But such a story certainly must discuss the fact that, while oyster farming is “environmentally sustainable,” our environmentally unsustainable climate policies — which are championed by Cuccinelli and his fellow deniers — make it unsustainable as a business enterprise. If acidification doesn’t devastate the industry in the next few decades, sea level rise will inevitably inundate the island.

http://thinkprogress.org/climate/2015/01/06/3608217/ken-cuccinelli-irony-alert/