The changing Arctic Ocean

The Arctic Ocean is becoming more like the Atlantic and Pacific, studies say

"In many respects, the Arctic Ocean now looks like a new ocean."

Arctic Today,

23 July, 2020

A new Arctic Ocean is emerging with more algae blooms, bigger waves and more similarities to the Atlantic and Pacific oceans, according to a series of recently released studies.

Blame — or credit — should go at least in part to the loss of sea ice and in the seas peripheral to the Arctic Ocean and the increase in heat that those peripheral seas are sending north, the separate studies say.

“In many respects, the Arctic Ocean now looks like a new ocean,” Igor Polyakov, an oceanographer with the University of Alaska Fairbanks and a lead author of one of the studies, said in a statement released by the university.

Polyakov’s study, published in the journal Frontiers in Marine Science, analyzes 37 years of data that track the “borealization” of the Arctic Ocean. But borealization means different things on the European side than on the American-Asian said, said the study, a collaborative effort between scientists at UAF, the Finnish Meteorological Institute and other institutions from the United States, Canada, Norway, Sweden and Russia.

The study identified temperature, chemical and biological changes in the Arctic Ocean that are being driven by the connected subarctic waters.

On the European side of the Arctic, where warmer Atlantic waters are flowing in from the Barents and Kara seas, there is more mixing of saltwater with freshwater, the study found. The mixing is enhancing biological productivity. In contrast, the American-Asian side of the Arctic, which is influenced by the Bering and Chukchi seas, is getting more freshwater from ice melt and river outflow, the study found. That freshwater lies atop heavier saltwater, reducing the mixing and potentially reducing future productivity, the study said.

The Atlantification of the European Arctic and the Pacification of the American-Asian Arctic are expected to continue into the future, Polyakov said. “Within several decades we will see probably increasing regional contrasts in the Arctic, as the current climate models suggest,” said by email.

A collapsed block of ice-rich permafrost along Drew Point, Alaska, at the edge of the Beaufort Sea. Increased wave action combined with permafrost thaw is likely to severely erode some Arctic coastlines. (USGS)

Another study, conducted by scientists at Stanford University and published in the journal Science, tracks found that primary production (the creation of energy, mostly through photosynthesis, that forms the base of food chains), increased by 57 percent between 1998 and 2018 in the Arctic Ocean.

The study identifies an ongoing regime shift, with thickening amounts of photosynthesizing algae creating much more net biological production.

The Stanford scientists in the past have examined the link between sea ice retreat and increased phytoplankton-driven production in the Arctic  Ocean. That work has included tracking of phytoplankton blooms beneath the ice in the Chukchi Sea and the relationship of ice retreat to phytoplankton blooms in the Bering Sea.

Now, the Arctic Ocean’s phytoplankton boom is no longer simply a product of more sunlight penetrating through the thinned ice or open waters, the study found. While loss of ice was the big driver of phytoplankton biomass increase during the first decade of the study period, a new factor became dominant in the second decade of the period; inflow of nutrients from the adjoining seas and oceans.

“We knew the Arctic had increased production in the last few years, but it seemed possible the system was just recycling the same store of nutrients,” Kate Lewis, the lead author, said in a statement released by Stanford. “Our study shows that’s not the case. Phytoplankton are absorbing more carbon year after year as new nutrients come into this ocean. That was unexpected, and it has big ecological impacts.”

Whether the ecological impacts of that increased productivity is a good or bad depends on the species, said co-author Kevin Arrigo, the head of Stanford’s Ocean Biogeochemistry Lab.

“There’s going to be winners and losers,” Arrigo said in the university’s statement. “A more productive arctic means more food for lots of animals. But many animals that have adapted to live in a polar environment are finding life more difficult as the sea ice retreats.”

One possible benefit would be increased absorption of atmospheric carbon, but the Arctic is too small to offset much of the world’s greenhouse-gas load and “it’s not something we’re going to be able to rely on to help us out of our climate problem,” Arrigo said in the statement.

Another change coming to the Arctic Ocean is a dramatic increase in wave action, according to a study by scientists from Environment and Climate Change Canada.

If current rates of carbon emissions continue, the biggest Arctic Ocean waves in areas close to shore can be expected to double or triple in height by the end of the century compared to conditions measured in the 1979-to-2005 period, according to the study, published in the journal JGR Oceans.

This would set up Arctic coastal residents for some potentially dire consequences. A particularly hotspot is likely to be the Beaufort Sea coast, already eroding dramatically because of greater wave action in increasingly open waters combined with the thaw of permafrost that previously helped hold shore bluffs intact. Storm events that used to have a 1-in-20 probability in the 1979-2005 period will become likely to occur every two to five years after 2080, according to the study.

“It increases the risk of flooding and erosion. It increases drastically almost everywhere,” lead author Mercè Casas-Prat said in a statement released by the American Geophysical Union. “This can have a direct impact to the communities that live close to the shoreline.”

Offshore, the biggest waves can up to 6 meters higher than levels seen from 1979 to 2005, the study said. The increasing influences of the Atlantic Ocean on the Arctic Ocean will be driving a lot of new wave action, and ocean waves will extend even to areas near the North Pole if current emissions levels are sustained, the study said.

Carbon-Saturated Oceans Headed Toward Tipping Point That Could Unleash Mass Extinction Event

'Completely Terrifying': Study Warns Carbon-Saturated Oceans Headed Toward Tipping Point That Could Unleash Mass Extinction Event

"Once we're over the threshold...you're dealing with how the Earth works, and it goes on its own ride."

by Julia Conley, staff writer

Common Dreams,

9 July, 2019

The continuous accumulation of carbon dioxide in the planet's oceans—which shows no sign of stopping due to humanity's relentless consumption of fossil fuels—is likely to trigger a chemical reaction in Earth's carbon cycle similar to those which happened just before mass extinction events, according to a new study.

MIT geophysics professor Daniel Rothman released new data on Monday showing that carbon levels today could be fast approaching a tipping point threshold that could trigger extreme ocean acidification similar to the kind that contributed to the Permian–Triassic mass extinction that occurred about 250 million years ago.

Rothman's new research comes two years after he predicted that a mass extinction event could take place at the end of this century. Since 2017, he has been working to understand how life on Earth might be wiped out due to increased carbon in the oceans.

"If we push the Earth system too far, then it takes over and determines its own response—past that point there will be little we can do about it."

—Timothy Lenton, University of Exeter

Rothman created a model in which he simulated adding carbon dioxide to oceans, finding that when the gas was added to an already-stable marine environment, only temporary acidification occurred.

When he continuously pumped carbon into the oceans, however, as humans have been doing at greater and greater levels since the late 18th century, the ocean model eventually reached a threshold which triggered what MIT called "a cascade of chemical feedbacks," or "excitation," causing extreme acidification and worsening the warming effects of the originally-added carbon.

Over the past 540 million years, these chemical feedbacks have occurred at various times, Rothman noted.

But the most significant occurances took place around the time of four out of the five mass extinction events—and today's oceans are absorbing carbon far more quickly than they did before the Permian–Triassic extinction, in which 90 percent of life on Earth died out.

The planet may now be "at the precipice of excitation," Rothman told MIT News.

On social media, one critic called the study's implications about life on Earth "completely terrifying."

The study, which was completed with support from NASA and the National Science Foundation, also notes that even though humans have only been pumping carbon into the oceans for hundreds of years rather than the thousands of years it took for volcanic eruptions and other events to bring about other extinctions, the result will likely be the same.

"Once we're over the threshold, how we got there may not matter," Rothman told MIT News. "Once you get over it, you're dealing with how the Earth works, and it goes on its own ride."

Other scientists said the study, which will be published this week in the Proceedings of the National Academy of Sciences, represents a clear call for immediate action to drastically reduce the amount of carbon that is being pumped into the world's oceans. Climate action groups and grassroots movements have long called on governments to impose a moratorium on fossil fuel drilling, which pumps about a billion metric tons of carbon into the atmosphere every year.

"We already know that our CO2-emitting actions will have consequences for many millennia," says Timothy Lenton, a professor of climate change and earth systems science at the University of Exeter. "This study suggests those consequences could be much more dramatic than previously expected."

"If we push the Earth system too far," Lenton added, "then it takes over and determines its own response—past that point there will be little we can do about it."

Scientific paper shows ocean temperature changes around NZ in last 30 years

Scientists confirm warming seas around New Zealand

NZ Herald,

25 January, 2019

The water in the New Zealand region is significantly warmer than it was 30 years ago, and all indications are the warming trend will continue, said a NIWA scientist.

Oceanographer Dr Phil Sutton is the lead author on a scientific paper published today, that analyses ocean temperature changes around New Zealand for the last 36 years.

He said the strongest warming near NZ has occurred off the Wairarapa Coast, and the weakest along the northeast coast between North and East Capes.

The increased warmth isn't only at the surface – around New Zealand the increased warmth penetrates in places to 200m deep while in the Tasman Sea it reaches down to at least 850m.

"Since 1981 we are talking of warming of about 0.1 to 0.3ᵒC per decade. That may not sound like a huge amount but slightly stronger warming of about 0.4ᵒC per decade off the east coast of Tasmania has resulted in significant changes to ecosystems which has led to concerns of similar impacts in New Zealand," Sutton said.

The results have been published in the New Zealand Journal of Marine and Freshwater Research.

Sutton and co-author Dr Melissa Bowen, of Auckland University, analysed three data sets and applied mathematical equations to determine if the changes were statistically significant.

The longest data set is daily satellite measurements of sea surface temperatures which began in 1981.

The second set is derived from ship-based measurements of the ocean down to 850m depth along two transects, or lines, from Sydney to Wellington which began in 1991, and Auckland to Suva which started in 1987.

The final data set was information from floats used in the Argo programme, an international network of floats in the world's oceans that measure temperature, salinity and currents in the top 2000m of the oceans.

The reporting on the NZ Herald is so bad it does not even privide a reference to this

Ocean temperature change around New Zealand over the last 36 years

Oceans Have Retained Far More Heat Than Previously Believed

'We Have Less Time Than We Thought': Alarming New Study Shows Oceans Have Retained Far More Heat Than Previously Believed

"The planet warmed more than we thought. It was hidden from us just because we didn't sample it right. But it was there. It was in the ocean already."

Commondreams,

31 October, 2018

Offering a stark warning that humanity may have even less time to drastically cut carbon emissions than the United Nations suggested in its latest alarming report on the climate crisis, new research (pdf) published in the journal Nature on Wednesday shows that Earth's oceans have retained 60 percent more heat each year over the past 25 years than scientists previously believed.

"We thought that we got away with not a lot of warming in both the ocean and the atmosphere for the amount of CO2 that we emitted. But we were wrong," Laure Resplandy, a geoscientist at Princeton University who led the new study, toldthe Washington Post. "The planet warmed more than we thought. It was hidden from us just because we didn't sample it right. But it was there. It was in the ocean already."

The U.N.'s Intergovernmental Panel on Climate Change argued in its report released earlier this month that humanity must cut carbon emissions in half by 2030 in order to avert climate catastrophe by 2040—but that timeframe was based on previous and possibly conservative estimates of global warming.

As the Post's Chris Mooney and Brady Dennis noted, "higher-than-expected amount of heat in the oceans means more heat is being retained within Earth's climate system each year, rather than escaping into space."

"In essence," they added, "more heat in the oceans signals that global warming is more advanced than scientists thought."

In a statement on Wednesday, Sierra Club executive director Michael Brune argued that the new research "confirms that we have even less time to move beyond dirty fossil fuels like coal, oil, and fracked gas to an economy powered by 100 percent clean, renewable energy."

"The world's oceans are the canaries in the coal mine when it comes to the climate crisis. The writing has been on the wall for years," Brune said. "This global crisis demands nothing less than swift and meaningful action by every world leader to ensure a safe and healthy future for all. The Trump administration's continued ignorance and lack of action is wholly unacceptable, and together with our allies across the country, we will work toward a brighter, healthier, and safer future for all."

Startling new research finds large buildup of heat in the oceans, suggesting a faster rate of global warming

The findings mean the world might have less time to curb carbon emissions.

The world’s oceans have been soaking up far more excess heat in recent decades than scientists realized, suggesting that Earth could be set to warm even faster than predicted in the years ahead, according to new research published Wednesday.

Over the past quarter-century, Earth’s oceans have retained 60 percent more heat each year than scientists previously had thought, said Laure Resplandy, a geoscientist at Princeton University who led the startling study published Wednesday in the journal Nature. The difference represents an enormous amount of additional energy, originating from the sun and trapped by Earth’s atmosphere — the yearly amount representing more than eight times the world’s annual energy consumption.

In the scientific realm, the new findings help resolve long-running doubts about the rate of the warming of the oceans before 2007, when reliable measurements from devices called “Argo floats” were put to use worldwide. Before that, differing types of temperature records — and an overall lack of them — contributed to murkiness about how quickly the oceans were heating up.

The higher-than-expected amount of heat in the oceans means more heat is being retained within Earth’s climate system each year, rather than escaping into space. In essence, more heat in the oceans signals that global warming is more advanced than scientists thought.

“We thought that we got away with not a lot of warming in both the ocean and the atmosphere for the amount of CO2 that we emitted,” said Resplandy, who published the work with experts from the Scripps Institution of Oceanography and several other institutions in the United States, China, France and Germany. “But we were wrong. The planet warmed more than we thought. It was hidden from us just because we didn’t sample it right. But it was there. It was in the ocean already.”

Wednesday’s study also could have important policy implications. If ocean temperatures are rising more rapidly than previously calculated, that could leave nations even less time to dramatically cut the world’s emissions of carbon dioxide, in the hope of limiting global warming to the ambitious goal of 1.5 degrees Celsius (2.7 degrees Fahrenheit) above preindustrial levels by the end of this century.

The world already has warmed one degree Celsius (1.8 degrees Fahrenheit) since the late 19th century. Scientists backed by the United Nations reported this month that with warming projected to steadily increase, the world faces a daunting challenge in trying to limit that warming to only another half-degree Celsius. The group found that it would take “unprecedented” action by leaders across the globe over the coming decade to even have a shot at that goal.

Meanwhile, the Trump administration has continued to roll back regulations aimed at reducing carbon emissions from vehicles, coal plants and other sources and has said it intends to withdraw from the Paris climate accord. In one instance, the administration relied on an assumption that the planet will warm a disastrous seven degrees Fahrenheit, or about four degrees Celsius, by the end of the century in arguing that a proposal to ease vehicle fuel-efficiency standards would have only minor climate impacts.

The new research underscores the potential consequences of global inaction. Rapidly warming oceans mean that seas will rise faster and that more heat will be delivered to critical locations that already are facing the effects of a warming climate, such as coral reefs in the tropics and the ice sheets of Greenland and Antarctica.

“In case the larger estimate of ocean heat uptake turns out to be true, adaptation to — and mitigation of — our changing climate would become more urgent,” said Pieter Tans, who is the leader of the Carbon Cycle Greenhouse Gases Group at the National Oceanic and Atmospheric Administration and was not involved in the study.

The oceans absorb more than 90 percent of the excess energy trapped within the world’s atmosphere.

The new research does not measure the ocean’s temperature directly. Rather, it measures the volume of gases, specifically oxygen and carbon dioxide, that have escaped the ocean in recent decades and headed into the atmosphere as it heats up. The method offered scientists a reliable indicator of ocean temperature change because it reflects a fundamental behavior of a liquid when heated.

“When the ocean warms, it loses some gas to the atmosphere,” Resplandy said. “That’s an analogy that I make all the time: If you leave your Coke in the sun, it will lose the gas.”

This approach allowed researchers to recheck the contested history of ocean temperatures in a different and novel way. In doing so, they came up with a higher number for how much warming the oceans have experienced over time.

“I feel like this is a triumph of Earth-system science. That we could get confirmation from atmospheric gases of ocean heat content is extraordinary,” said Joellen Russell, a professor and oceanographer at the University of Arizona. “You’ve got the A team here on this paper.”

But Russell said the findings are hardly as uplifting.

The report “does have implications for climate sensitivity, meaning, how warm does a certain amount of CO2 make us?” Russell said, adding that the world could have a smaller “carbon budget” than once thought. That budget refers to the amount of carbon dioxide humans can emit while still being able to keep warming below dangerous levels.

The scientists calculated that because of the increased heat already stored in the ocean, the maximum emissions that the world can produce while still avoiding a warming of two degrees Celsius (3.6 Fahrenheit) would have to be reduced by 25 percent. That represents a very significant shrinkage of an already very narrow carbon “budget.”

The U.N. panel of climate scientists said recently that global carbon emissions must be cut in half by 2030 if the world hopes to remain beneath 1.5 Celsius of warming. But Resplandy said that the evidence of faster-warming oceans “shifts the probability, making it harder to stay below the 1.5-degree temperature target."

Understanding what is happening with Earth’s oceans is critical, because they, far more than the atmosphere, are the mirror of ongoing climate change.

According to a major climate report released last year by the U.S. government, the world’s oceans have absorbed about 93 percent of the excess heat caused by greenhouse gases since the mid-20th century. Scientists have found that ocean heat has increased at all depths since the 1960s, while surface waters also have warmed. The federal climate report projected a global increase in average sea surface temperatures of as much as nearly five degrees Fahrenheit by 2100 if emissions continue unabated, with even higher levels of warming in some U.S. coastal regions.

The world’s oceans also absorb more than a quarter of the carbon dioxide emitted annually from human activities — an effect making them more acidic and threatening fragile ecosystems, federal researchers say. “The rate of acidification is unparalleled in at least the past 66 million years,” the government climate report stated.

Paul Durack, a research scientist at the Lawrence Livermore National Laboratory in California, said Wednesday’s study offers “a really interesting new insight” and is “quite alarming.”

The warming found in the study is “more than twice the rates of long-term warming estimates from the 1960s and ’70s to the present,” Durack said, adding that if these rates are validated by further studies, “it means the rate of warming and the sensitivity of the Earth’s system to greenhouse gases is at the upper end.” He said that if scientists have underestimated the amount of heat taken up by the oceans, “it will mean we need to go back to the drawing board” on the aggressiveness of mitigation actions the world needs to take promptly to limit future warming.

Beyond the long-term implications of warmer oceans, Russell added that in the short term, even small changes in ocean temperatures can affect weather in specific places. For instance, scientists have said warmer oceans off the coast of New England have contributed to more-intense winter storms.

“We’re only just now discovering how important ocean warming is to our daily lives, to our daily weather,” she said.

Could the Hot Pacific Blob Become Permanent

How Arctic Sea Ice Loss Could Make the Hot Pacific Blob Permanent 

Robertscribbler,

21 June, 2018

From the North Pacific to the tropics, loss of sea ice will result in a vastly heated Pacific Ocean in which events like the recent Hot Blob become far more common. Those were the conclusions of a new model study conducted by Wang, Deser, Sun and Tomas and recently published in Geophysical Research Letters.

(Understanding how sea ice loss in the Arctic can result in large-scale Pacific warming.)

An ocean heating event called the Blob resulted in mass loss of sea life during the period of 2013-2014. It was associated with a towering high pressure ridge in which the upper level winds ran far to the north and into the Arctic. Beneath the ridge, temperatures both at the land and ocean surface grew to be much warmer than normal.

Though viewed as a fluke by some, many began to draw connections between the powerful ridge feature, the related Pacific warming, and sea ice loss in the Arctic. Now, a new scientific study using climate models has produced some rather telling findings. First, the study found that Arctic sea ice loss results in large scale Pacific Ocean warming within just 10-20 years of widespread Arctic Ocean ice reductions. 

Second, the study models indicated that warming occurred first and strongest in the North Pacific, but then rapidly translated toward the Equator.

(Sea surface temperatures across the North Pacific were much warmer than normal during the hot Blob event of 2013-2014. A new model study finds that sea ice loss will make such extreme events common.)

The reason for this change in planetary and Pacific Ocean energy balance is scientifically described as a teleconnection. In very basic terms, loss of sea ice at the Arctic Ocean surface produces changes in local wind patterns that ripple through the global atmosphere. After a rather short period of time, wind patterns in the upper levels of the atmosphere and at the surface in the Pacific Ocean become involved.

Winds are often the vehicle by which energy is transferred throughout the atmosphere and at the surface. So a change in winds, from the top of the atmosphere to the bottom, can swiftly translate to a change in surface temperatures.

(A new model study shows radical changes in Pacific sea surface temperatures in response to Arctic Ocean sea ice loss.)

Looking at the study, it appears more likely now that the Northern Pacific Hot Blob of 2013-2014 was not a fluke, but instead an early knock-on effect of Arctic sea ice loss. A kind of event that will tend to become commonplace as the Arctic Ocean ice continues to melt. And that eventually, sooner rather than later, the heat build-up in the North Pacific will translate south to the Equator. First warming the Eastern Pacific in a more persistent El Nino type pattern and then spreading west (see image above).

As with the Blob, everything from the health of sea life to the intensity of extreme weather would be substantially impacted by such large scale changes. In other words, it looks like large scale losses of Arctic sea ice are enough to affect a broad and disruptive change in the global climate regime.

Models used to estimate past ocean temperatures might be based on a flawed assumption

Scientists Just Found a Serious Flaw in Ocean Temperature Calculations

Oh no.

Science Alert,

17 October, 2017

Models used to estimate past ocean temperatures might be based on a flawed assumption, according to new research.

If true, it would mean our ancient seas were far cooler than previously calculated, and our planet's current warming trend is even more extraordinary than we thought.

A team of scientists from some of Europe's leading research institutes has taken a critical look at a chemical process that has served as a proxy for determining the temperatures of oceans millions of years in the past.

Even the most solid of scientific models rests on fairly well-reasoned assumptions.

In this case, the method for calculating temperature was based on the thought that temperatures were preserved perfectly inside tiny marine organisms called foraminifera.

Specifically, the exact ratio of oxygen-18 to oxygen-16 in the calcite of the organisms' exoskeletons varies with the isotope concentrations in the environment – a factor that was determined by things like acidity and salinity – and the water's temperature.

So if we determine the differences in the oxygen isotopes in fossils, we have a record of the temperatures as they were when they lived a little over 100 million years ago.

This tells us the temperature of the deeper parts of the ocean at the tropics were about 15 degrees Celsius warmer than today.

Yet it turns out things might not be quite so straightforward.

"What appeared to be perfectly preserved fossils are in fact not," says Sylvain Bernard, a mineralogist from the French National Center for Scientific Research.

Evidence now suggests the ratio of oxygen-18 to oxygen-16 in the buried marine life might not be quite as stable as thought.

To test how the chemistry of the calcite in the foraminifera's shells might continue to change over time, the researchers placed a sample of the organisms in artificial sea water that contained just isotopes of oxygen-18.

They then cranked the temperature to simulate the heat generated by being buried beneath a pile of sediment and used a device called a nanoscale secondary ion mass spectrometer (or NanoSIMS) to analyse changes in the calcite's oxygen ratios.

Sure enough, the equilibrium shifted, changing the ratios.

"This means that the paleotemperature estimates made up to now are incorrect," says Bernard.

Taken at face value, it implies the waters probably weren't all that much warmer than today. The discovery also helps resolve a paradox that has hinted at an inconsistency in the most favoured models.

Using the oxygen isotope method, ocean temperatures in the tropics during the warm Cretaceous period weren't all that different to the surface temperatures at the poles.

Unfortunately other models on climate and ocean currents don't gel with this shallow gradient, hinting at a problem

In addition, analysing magnesium isotopes in the foraminifera fossils instead of oxygen suggests the sea surface temperatures at higher latitudes were also colder than estimated.

For all of the changes our planet has experienced over the past 100 million years, our oceans have remained pretty stable as far as temperature goes. Cast in that light, today's rapid global warming trend is even more dramatic than we'd thought.

The next step for researchers is to go back to the drawing board on existing data and see exactly what difference the changes make to historical records.

"To revisit the ocean's paleotemperatures now, we need to carefully quantify this re-equilibration, which has been overlooked for too long," says geochemist Anders Meibom from the Swiss Federal Institute of Technology in Lausanne.

"For that, we have to work on other types of marine organisms so that we clearly understand what took place in the sediment over geological time."

We truly are living in an extraordinary period of our planet's history.

This research was published in Nature Communications.