The Great London [Search results for Arctic] 

For each ton of carbon dioxide (CO2) that any person on our planet emits, 3 m² of Arctic summer sea ice disappear. This is the finding of a new study that has been published in the journal Science this week by Dr. Dirk Notz, leader of Max Planck research group "Sea Ice in the Earth System" at the Max Planck Institute for Metorology (MPI-M) and by Prof. Julienne Stroeve from the National Snow and Ice Data Centre in Boulder, Colorado, and the University College London, UK. These numbers allow one for the first time to grasp the individual contribution to global climate change. The study also explains why climate models usually simulate a lower sensitivity - and concludes that the 2 °C global warming target will not allow Arctic summer sea ice to survive.

The rapid retreat of Arctic sea ice is one of the most direct indicators of the ongoing climate change on our planet. Over the past forty years, the ice cover in summer has shrunk by more than half, with climate model simulations predicting that the remaining half might be gone by mid century unless greenhouse gas emissions are reduced rapidly. However, a number of studies have indicated that climate models underestimate the loss of Arctic sea ice, which is why the models might not be the most suitable tools to quantify the future evolution of the ice cover.

To address this issue, a new study in the >journal Science now derives the future evolution of Arctic summer sea ice directly from the observational record. To do so, the authors examine the link between carbon-dioxide emissions and the area of Arctic summer sea ice, and find that both are linearly related. "The observed numbers are very simple", explains lead author Dirk Notz. "For each ton of carbon dioxide that a person emits anywhere on this planet, 3 m² of Arctic summer sea ice disappear." And his co-author Julienne Stroeve from adds: "So far, climate change has often felt like a rather abstract notion. Our results allow us to overcome this perception. For example, it is now straight-forward to calculate that the carbon dioxide emissions for each seat on a return flight from, say, London to San Francisco causes about 5 m² of Arctic sea ice to disappear."

The study also explains the linear relationship between carbon-dioxide emissions and sea-ice loss. "Put simply, for each ton of carbon dioxide emission, the climate warms a little bit. To compensate for this warming, the sea-ice edge moves northward to a region with less incoming solar radiation. This then causes the sea-ice area to shrink. Simple geometric reasons cause these processes to combine to the observed linearity", explains Notz.

Climate models also simulate the observed linear relationship between sea-ice area and CO2 emissions. However, they usually have a much lower sensitivity of the ice cover than has been observed. The Science study finds that this is most likely because the models underestimate the atmospheric warming in the Arctic that is induced by a given carbon-dioxide emission. "It seems that it's not primarily the sea-ice models that are responsible for the mismatch. The ice just melts too slow in the models because their Arctic warming is too weak", says Stroeve.

Regarding the future evolution of Arctic sea ice, the new study finds that the internationally agreed 2 °C global warming target is not sufficient to allow Arctic summer sea ice to survive. Given the observed sensitivity of the ice cover, the sea ice is gone throughout September once another 1000 gigatons of carbon dioxide have been emitted. This amount of emissions is usually taken as a rough estimate of the allowable emissions to reach the 2 °C global-warming target. Only for the much lower emissions that would allow one to keep global warming below 1.5 °C, as called for by the Paris agreement, Arctic summer sea ice has a realistic chance of long-term survival, the study concludes. 

Source: Max Planck Society [November 04, 2016]

Beneath the Aurora Borealis an oil tanker glides through the night past the Coast Guard ice breaker Amundsen and vanishes into the maze of shoals and straits of the Northwest Passage, navigating waters that for millennia were frozen over this time of year.

Warming has forced a retreat of the polar ice cap, opening up a sea route through the Canadian Arctic Archipelago and connecting the Atlantic and Pacific Oceans for several months of the year.

Commander Alain Lacerte is at the helm as the vessel navigates the Queen Maud Gulf, poring over charts that date from the 1950s and making course corrections with the help of GPS.

"Where it's white (on the chart), it means the area hasn't been surveyed," he explains -- leaning over a map that is mostly white. "Most of the far north hasn't been surveyed, so our maps are unreliable."

The crew constantly take radar and multi-beam sonar measurements and check their position.

"We don't want any shoals named after us," says the old sea dog from behind his spectacles.

Almost the size of the European Union, the Canadian Arctic seabed remains largely uncharted. The waters are also shallow and navigating unknown parts can be deadly -- even when the north is ice-free.

Today, taking this route cuts 7,000 kilometers (4,350 miles) off a trip from London to Tokyo, saving time and fuel.

'Never imagined this'

Since the 15th century there have been a dozen expeditions seeking a faster shipping route from Europe to Asia through the north.

The Norwegian explorer Roald Amundsen was the first to cross the Northwest Passage, on board the Gjoa, in an expedition that took three years, finishing in 1906.

Afterward interest in the waterway waned. An average of one ship per year attempted to make the crossing over the past century.

But thawing of the polar ice promises Arctic nations new opportunities to open ocean trade routes and offshore oil fields.

In the summer months the Amundsen is used by Canadian government scientists -- among them Roger Provost, a Canadian Ice Service meteorologist -- as well as a network of scientists led by the ArcticNet organization.

Provost looked with amazement from the wheelhouse at the lack of any ice cover around the coast guard ship.

"Anyone who still denies climate change is real has their head in the ground, they're blind," he said.

In 37 years of Arctic exploration, he said he "never imagined ever seeing this," pointing to satellite images showing a clear path through the Queen Maud Gulf and the M'Clintock Channel, where the Amundsen is headed.

Almost 112 years ago to the day, the explorer Amundsen got stuck in the pack ice here. And in 1979, Provost recalls, another Canadian Coast Guard ice-breaker had to cut short its inaugural journey, unable to push beyond this point through thick ice.

Over the past five years the number of cargo and cruise ships, tankers and others crossing the Passage climbed to 117.

In 2010, Canada imposed shipping regulations on seafarers going through the Passage, but the United States and the European Union do not recognize Canada's ownership of the waterway, considering it international waters.

'Completely disappear'

The ice cover has steadily retreated over the past decade, with this year set to be the hottest on record, according to the US National Oceanic and Atmospheric Administration.

The previous year saw average global temperatures rise one degree Celsius -- but by three degrees in the Arctic.

What most worries Provost is the loss of "multi-year ice," formed over centuries. "In a few years it will completely disappear," he forecast.

"It's a tragedy for all humanity what is happening."

Glaciologist Lauren Candlish said: "We're now in the transition phase, from having multi-year ice through the entire summer, to a seasonally ice free Arctic."

Poring over data on her computer in a nook of the ship the University of Manitoba researcher says: "It's a different Arctic now. Less predictable, with more fluctuations."

The last such melting occurred "before the last ice age," from AD 100,000 to AD 10,000, she noted.

Most aboard the ship doubt we are headed for an Arctic shipping boom predicted by many, as the weather remains unpredictable and harsh. But there is sure to be an increase, which raises concerns for the environment.

"When it was covered in ice, this ecosystem was not threatened," says Provost. The Arctic is a unique and diverse ecosystem that is home to whales, seals, polar bears, walruses and several bird species.

"A massive oil spill like the one in the Gulf of Mexico in 2010 must never happen in the Arctic," he said. "The consequences would be much more serious."

Author: Clement Sabourin | Source: AFP [October 20, 2015]

The build-up and subsequent release of warm, stagnant water from the deep Arctic Ocean and Nordic Seas played a role in ending the last Ice Age within the Arctic region, according to new research led by a UCL scientist.

The study, published today in Science, examined how the circulation of the ocean north of Iceland -- the combined Arctic Ocean and Nordic Seas, called the Arctic Mediterranean -- changed since the end of the last Ice Age (~20,000-30,000 years ago).

Today, the ocean is cooled by the atmosphere during winter, producing large volumes of dense water that sink and flush through the deep Arctic Mediterranean. However, in contrast to the vigorous circulation of today, the research found that during the last Ice Age, the deep Arctic Mediterranean became like a giant stagnant pond, with deep waters not being replenished for up to 10,000 years.

This is thought to have been caused by the thick and extensive layer of sea ice and fresh water that covered much of the Arctic Mediterranean during the Ice Age, preventing the atmosphere from cooling and densifying the underlying ocean.

Dr David Thornalley (UCL Geography) said: "As well as being stagnant, these deep waters were also warm. Sitting around at the bottom of the ocean, they slowly accumulated geothermal heat from the seafloor, until a critical point was reached when the ocean became unstable.

"Suddenly, the heat previously stored in the deep Arctic Mediterranean was released to the upper ocean. The timing of this event coincides with the occurrence of evidence for a massive release of meltwater into the Nordic Seas. We hypothesize that this input of melt water was caused by the release of deep ocean heat, which melted icebergs, sea-ice and surrounding marine-terminating ice sheets."

This study highlights the important impact that changes in ocean circulation can have on climate, due to the ocean's capacity to redistribute vast quantities of heat around the globe. For example, scientists are currently concerned that ongoing changes in ocean circulation may result in warmer subsurface water that will cause enhanced melting and retreat of certain ice sheets in Greenland and Antarctica.

Dr Thornalley added: "To help predict the role of the ocean in future climate change, it is useful to investigate how ocean circulation changed in the past and what the associated climate effects were."

In this study, researchers from UCL, Woods Hole Oceanographic Institute and other partner institutions analysed the composition of calcite shells of small single-celled organisms (called foraminifera) that are found in ocean floor sediment. The shells of these organisms record the chemistry of the deep ocean at the time they were living, enabling the researchers to reconstruct past changes in ocean circulation.

By measuring the radiocarbon content of these shells, the research team was able to determine how rapidly deep water was being formed in the Arctic Mediterranean. A number of different techniques were then used to constrain past temperature changes, including measuring the ratio of magnesium and calcium, and the arrangement of isotopes of carbon and oxygen within the calcite shells of the foraminifera, both of which vary according to the temperature of the water in which the foraminifera grew.

A warmer, deep Arctic Mediterranean during glacial times has been suggested in previous studies, too. As summarised by co-author Dr Henning Bauch (GEOMAR/Germany) "It is good to see that new, independent proxy data would give strong support now to these former hypotheses."

Source: University College London [August 13, 2015]

Arctic sea ice has reached its lowest winter point since satellite observations began in the late 1970s, raising concerns about faster ice melt and rising seas due to global warming, US officials said Thursday.

The maximum extent of sea ice observed was 5.6 million square miles (14.5 million square kilometers) on February 25, earlier than scientists had expected, said the report by the National Snow and Ice Data Center.

"It is also the lowest in the satellite record," the NSIDC said.

Below-average ice conditions were observed everywhere except in the Labrador Sea and Davis Strait.

The sea ice was about 425,000 square miles below the average from 1981 to 2010, a loss equal to more than twice the size of Sweden.

It was also 50,200 square miles below the previous lowest maximum that occurred in 2011.

Environmentalists said the report offered more evidence of worsening global warming, and urged action to curb the burning of fossil fuels that send greenhouse gases into the atmosphere.

"This is further evidence that global warming and its impacts have not stopped despite the inaccurate and misleading claims of climate change 'skeptics,'" said Bob Ward of the Grantham Research Institute on Climate Change and the Environment at the London School of Economics and Political Science.

"The gradual disappearance of ice is having profound consequences for people, animals and plants in the polar regions, as well as around the world, through sea level rise."

The World Wildlife Fund said the loss of sea ice means trouble for a vast web of life that depends on it, from polar bears to marine creatures.

"Today's chilling news from the Arctic should be a wakeup call for all of us," said Samantha Smith, leader of the WWF Global Climate and Energy Initiative.

"Climate change won't stop at the Arctic Circle. Unless we make dramatic cuts in polluting gases, we will end up with a climate that is unrecognizable, unpredictable and damaging for natural systems and people."

The NSIDC said much of the ice loss could be attributed to an unusually warm February in parts of Russia and Alaska, and that it was still possible that a late-season surge of ice growth could occur.

A detailed analysis of the winter sea ice from 2014 to 2015 is due to be released in early April.

Source: AFP [March 19, 2015]

The appearance of infectious diseases in new places and new hosts, such as West Nile virus and Ebola, is a predictable result of climate change, says a noted zoologist affiliated with the Harold W. Manter Laboratory of Parasitology at the University of Nebraska-Lincoln.

In an article published online today in conjunction with a special issue of the Philosophical Transactions of the Royal Society B, Daniel Brooks warns that humans can expect more such illnesses to emerge in the future, as climate change shifts habitats and brings wildlife, crops, livestock, and humans into contact with pathogens to which they are susceptible but to which they have never been exposed before.

"It's not that there's going to be one 'Andromeda Strain' that will wipe everybody out on the planet," Brooks said, referring to the 1971 science fiction film about a deadly pathogen. "There are going to be a lot of localized outbreaks putting pressure on medical and veterinary health systems. It will be the death of a thousand cuts."

Brooks and his co-author, Eric Hoberg, a zoologist with the U.S. National Parasite Collection of the USDA's Agricultural Research Service, have personally observed how climate change has affected very different ecosystems. During his career, Brooks has focused primarily on parasites in the tropics, while Hoberg has worked primarily in Arctic regions.

Each has observed the arrival of species that hadn't previously lived in that area and the departure of others, Brooks said.

"Over the last 30 years, the places we've been working have been heavily impacted by climate change," Brooks said in an interview last week. "Even though I was in the tropics and he was in the Arctic, we could see something was happening." Changes in habitat mean animals are exposed to new parasites and pathogens.

For example, Brooks said, after humans hunted capuchin and spider monkeys out of existence in some regions of Costa Rica, their parasites immediately switched to howler monkeys, where they persist today. Some lungworms in recent years have moved northward and shifted hosts from caribou to muskoxen in the Canadian Arctic.

But for more than 100 years, scientists have assumed parasites don't quickly jump from one species to another because of the way parasites and hosts co-evolve.

Brooks calls it the "parasite paradox." Over time, hosts and pathogens become more tightly adapted to one another. According to previous theories, this should make emerging diseases rare, because they have to wait for the right random mutation to occur.

However, such jumps happen more quickly than anticipated. Even pathogens that are highly adapted to one host are able to shift to new ones under the right circumstances.

Brooks and Hoberg call for a "fundamental conceptual shift" recognizing that pathogens retain ancestral genetic capabilities allowing them to acquire new hosts quickly.

"Even though a parasite might have a very specialized relationship with one particular host in one particular place, there are other hosts that may be as susceptible," Brooks said.

In fact, the new hosts are more susceptible to infection and get sicker from it, Brooks said, because they haven't yet developed resistance.

Though resistance can evolve fairly rapidly, this only changes the emergent pathogen from an acute to a chronic disease problem, Brooks adds.

"West Nile Virus is a good example - no longer an acute problem for humans or wildlife in North America, it nonetheless is hhere to stay," he said.

The answer, Brooks said, is for greater collaboration between the public and veterinary health communities and the "museum" community - the biologists who study and classify life forms and how they evolve.

In addition to treating human cases of an emerging disease and developing a vaccine for it, he said, scientists need to learn which non-human species carry the pathogen.

Knowing the geographic distribution and the behavior of the non-human reservoirs of the pathogen could lead to public health strategies based on reducing risk of infection by minimizing human contact with infected animals, much likethose that reduced the incidence of malaria and yellow fever by reducing human contact with mosquitos.

Museum scientists versed in understanding the evolutionary relationships among species could use this knowledge to anticipate the risk of the pathogen becoming established outside of its native range.

Brooks, who earned his bachelor's and master's degrees from the University of Nebraska-Lincoln, was a zoology professor at the University of Toronto for 30 years until he retired early in 2011 to devote more time to his study of emerging infectious disease. In addition to being a senior research fellow with UNL's Manter Laboratory, he is a visiting senior fellow at the Universidade Federal do Parana, Brazil, funded by the Ciencias sem Fronteiras (Sciences without Borders) of the Brazilian government, and a visiting scholar with Debrecen University in Hungary.

Brooks' and Hoberg's article, "Evolution in action: climate change, biodiversity dynamics and emerging infectious disease," is part of a Philosophical Transactions of the Royal Society B issue on "Climate change and vector-borne diseases of humans," edited by Paul Parham, a specialist in infectious disease epidemiology at Imperial College in London.

"We have to admit we're not winning the war against emerging diseases," Brooks said. "We're not anticipating them. We're not paying attention to their basic biology, where they might come from and the potential for new pathogens to be introduced."

Source: University of Nebraska-Lincoln [February 16, 2015]

Working closely with the U.S. Forest Service and the Sitka Tribe of Alaska, an international team of researchers funded by the National Science Foundation has begun to piece together an archaeological and historical narrative of how the crew of the wrecked 19th century Russian-American Company sailing ship Neva survived the harsh subarctic winter.

"The items left behind by survivors provide a unique snapshot-in-time for January 1813, and might help us to understand the adaptations that allowed them to await rescue in a frigid, unfamiliar environment for almost a month," said Dave McMahan of the Sitka Historical Society.

McMahan is the principal investigator for the NSF award, which was made by the Arctic Sciences Section in NSF's Division of Polar Programs.

The wreck of the frigate Neva, which occurred near the city of Sitka, has been surrounded by stories and legends for two centuries. Although survivors eventually were rescued and taken to Sitka, few accounts of their experience were collected or published. No official records relating to the wreck and its aftermath have been discovered.

The researchers are seeking to verify the wreck location and confirm the site of a survivor camp. They also hope that Tlingit oral history will add to the story and help to place the wreck in a broader context.

The NSF-funded work stems from a 2012 survey project by the U.S. Forest Service, the Alaska Office of History and Archaeology and the Sitka Historical Society. At that time, archaeologists discovered caches of Russian axes at a location they predicted to be the survivor camp.

The archaeological team--which includes members from Russia, the U.S. and Canada--believes articles they found over the past two years represent the everyday tools used by 26 shipwrecked members of the Neva's crew. Those crewmembers survived for almost a month in the winter of 1813 by foraging and gathering materials that washed ashore from the wreck.

In July, researchers discovered at the campsite a series of hearths with early 19th century artifacts such as gun flints, musket balls, pieces of modified sheet copper, iron and copper spikes, a Russian axe, and a fishhook fashioned from copper. Well-preserved food middens--or refuse heaps--will allow reconstruction of the foraging strategies the sailors used to survive.

Gun flints found at the site appeared to have been used by survivors to used start fires, by striking them against steel. Historical accounts credit a firearm used in this manner with helping save the crew from hypothermia. Physical evidence indicates the survivors tried to whittle down musket balls to fit a smaller caliber weapon, such as a flintlock--most likely the same firearm mentioned in the historical accounts. Some of the copper spikes recovered by archaeologists had been broken through shear stress, such as a wreck would produce. The researchers believe one copper or brass artifact is part of a set of a navigator's dividers, saved by a crewman as the ship violently broke apart over rocks.

The nature of the artifacts seems to strongly indicate that survivors of the shipwreck were active in ensuring their own survival. They modified wreckage in desperation, but with ingenuity.

"Collectively, the artifacts reflect improvisation in a survival situation, and do not include ceramics, glass and other materials that would be associated with a settlement," McMahan said.

Because the wreck occurred in an area of profound cultural significance to the Tlingit people of Sitka, the team did not search for--nor did it inadvertently discover--any graves of those who perished.

A famed vessel

Before its Arctic demise, the Neva was famous as one of two vessels that completed the first Russian circumnavigation of the globe from 1803-1807. The ship later fought in the 1804 Battle of Sitka, a pivotal engagement in the Russian struggle for control over what was then the Alaska territory. After 1808, the ship was in the exclusive service of the Russian-American Company, which Tsar Paul I chartered to establish new settlements in Russian America, primarily Alaska, and carry out a program of colonization.

The Neva came to grief after leaving the Siberian port of Okhotsk for Sitka in late August of 1812, McMahan said. During a grueling three-month voyage, those on board endured water shortages and sickness. Fierce storms damaged the ship's rigging. In mid-November the weakened sailors finally found shelter in Alaska's Prince William Sound and, after much debate, made a desperate attempt to reach Sitka.

In favorable weather, they almost reached their destination before wrecking off Kruzof Island. The wreck killed 32; another 15 had already died at sea. Of the 28 who made it to shore, 26 survived for almost a month before their rescue.

McMahan said the team hopes to continue the investigation next year with a smaller field effort at the camp. The terrestrial archaeology is only one component of research, which also includes underwater work and archival research, he said. Thick kelp that obscured the sea floor and interfered with sonar hampered an underwater survey this season. McMahan and Evguenia Anitchenko, the project's archival coordinator, conducted research in St. Petersburg last September, and plan to do the same later this year in London, where the Neva was built.

In an effort to put together the most complete story possible, McMahan is also encouraging anyone with information or oral history pertaining to the Neva to contact him through the Sitka Historical Society. "One goal of the research is to replace some of the myths and 'lore of the sea' with scientific findings," he said.

Longer-range plans for the project include a "virtual museum" with 3-D scans of artifacts, along with a short film that can be used in local educational curricula.

Source: National Science Foundation [September 10, 2015]

Trekking across the high Canadian Arctic almost 20 years ago, Howie Scher had an unexpected encounter that helped fix the course of his career.

An undergraduate on a research expedition over summer break, Scher was part of a scientific group traveling deep into the Arctic Circle to collect basalt cores for paleomagnetic analysis. But as focused as the team was on finding rocks with magnetic minerals that can help establish where on Earth they had formed, it was stony deposits that had once been very much alive that really caught the team's collective eye.

"We stumbled across a fossil bone bed there," Scher says. "We were pulling out vertebrate fossils--crocodilians, turtles, bony fish--and when we got home we showed them to a paleontologist who told us it was a warm water assemblage. That was a great experience as a freshman in college, and it got me very interested in climate--just seeing how it had been so different in the past than what my experience was near the North Pole, trudging through the snow."

Now an associate professor at the University of South Carolina, Scher has made a career of climate science. He is part of an international team that recently published a report pinpointing the genesis of one of the cornerstones of the Earth's current climate system, the Antarctic Circumpolar Current.

A constant eastward flow of ocean water in the Southern Ocean encircling Antarctica, the Antarctic Circumpolar Current is akin to the Gulf Stream, the current that moves water through the Atlantic Ocean from the tip of Florida, along the east coast of North America, and, by extension into the North Atlantic Current, to the shores of western and northern Europe. The Gulf Stream's transport of warm southern waters northward is why many European countries have more temperate climates than would be expected purely from their latitudes (relatively mild London, for example, lies more than 500 miles further north than Toronto).

But if the Atlantic Circumpolar Current is something like the Gulf Stream, there's a notable difference: it's even bigger.

"It's the largest ocean current today, and it's the only one that connects all the ocean basins," Scher says. "The Atlantic, Pacific and the Indian are huge oceans, but they're all bounded by continents; they have firm boundaries. The Southern Ocean, around Antarctica, is the only band of latitude where there's an ocean that goes continuously around the globe. Because of that, the winds that blow over the Southern Ocean are unimpeded by continental barriers.

"So the distance that the wind can blow over the ocean, which as oceanographers we call the 'fetch,' is infinite. And fetch is one of the things that determines how high the waves are, how much mixing goes on in the oceans, and ultimately what drives surface ocean currents. With infinite fetch, you can have a very strong ocean current, and because this particular band of ocean connects all of the world's oceans, it transports heat and salt and nutrients all around the world."

In a paper recently published in the journal Nature, Scher and his team make the case for just when this massive ocean current first started flowing. One straightforward obstacle in the distant past was the arrangement of continental masses. Antarctica and Australia were part of a single super-continent, Gondwana, and began to separate about 83 million years ago, so the Pacific and Indian Oceans couldn't have been in contact near the South Pole before then.

It was much later than the initial separation of Australia and Antarctica that deep ocean currents could flow between the two continents, though. Paleoceanographers have identified a transition, the opening of the Tasmanian gateway, a deep-water channel between Tasmania and Antarctica, as being a necessary part of any large-scale, sustained flow on the order of the Antarctic Circumpolar Current.

Using novel information about the separation of Antarctica and Australia, Scher and his team developed a tectonic model that showed that the Tasmanian gateway first developed at least 500 meters of depth some time between 35 and 32 million years ago.

From geochemical analyses of sediment core, however, they concluded that the channel opening to that depth wasn't enough to get the Antarctic Circumpolar Current flowing. The Pacific Ocean is in contact with much younger rock than the Indian Ocean, Scher says, which leads to a distinguishing concentration in each ocean of one isotope of neodymium that has a half-life longer than that of the solar system.

By measuring neodymium isotope compositions incorporated into fish teeth fossils in core samples, the team was able to establish that eastward current flow between the Pacific and Indian Oceans didn't begin until about 30 million years ago, some 2 to 5 million years after the Tasmanian gateway opened.

Taking both geophysical and geochemical data into account, they conclude that although the Tasmanian gateway was wide enough to accommodate a deep current, the gateway was located too far south to be in contact with the mid-latitude trade winds, which are the driving force for today's eastward-flowing Antarctic Circumpolar Current.

Instead, when the gateway first opened, water initially flowed westward, the opposite of that today, in keeping with the prevailing polar winds located at the more southern latitudes.

Only as both continents, and the gateway between the two, drifted northward on their tectonic plates over the next several million years did alignment with the trade winds come about. That reversed the current flow, to the east, and the Antarctic Circumpolar Current was born.

"It's the global mix-master of the oceans--that's a quote from Wally Broecker [of Columbia University's Lamont-Doherty Earth Observatory], and that's what it's been called by oceanographers for 50 years now," Scher says. "The Antarctic Circumpolar Current is the world's largest current today, it influences heat exchange and carbon exchange, and we really didn't know for how long it's been operating, which I call a major gap in our command of Earth history. It was a cool outcome."

Author: Steven Powell  | Source: University of South Carolina [August 25, 2015]

Research published in the American Geophysical Union's journal >Global Biogeochemical Cycles shows that recent rises in levels of methane in our atmosphere is being driven by biological sources, such as swamp gas, cow burps, or rice fields, rather than fossil fuel emissions.

Atmospheric methane is a major greenhouse gas that traps heat in our atmosphere, contributing to global warming. Its levels have been growing strongly since 2007, and in 2014 the growth rate of methane in the atmosphere was double that of previous years, largely driven by biological sources as opposed to fossil fuel emissions.

Conventional wisdom refuted

The study, led by researchers at Royal Holloway, University of London shows that methane emissions have been increasing, particularly in the tropics. Researchers discovered that biological sources, such as methane emissions from swamps, make up the majority of increase.

"Our results go against conventional thinking that the recent increase in atmospheric methane must be caused by increased emissions from natural gas, oil, and coal production. Our analysis of methane's isotopic composition clearly points to increased emissions from microbial sources, such as wetlands or agriculture" said lead author Euan Nisbet from Royal Holloway, University of London's Department of Earth Sciences.

Methane growth rate doubles

Professor Nisbet says "Atmospheric methane is one of the most potent greenhouses gases. Methane increased through most of the 20th century, driven largely by leaks from the gas and coal industries."

He continued, "At the beginning of this century it appeared that the amount of methane in the air was stabilising, but since 2007 the levels of methane have started growing again. The year 2014 was extreme, with the growth rate doubling, and large increases seen across the globe."

Tropics identified as key source

The research shows that in recent years, the increase in methane has been driven by sharp increases in the tropics, in response to changing weather patterns. It is possible that the natural processes that remove methane from the atmosphere have slowed down, but it is more likely that there's been an increase of methane emission instead, especially from the hot wet tropics.

Professor Nisbet and his team, together with the US The National Oceanic and Atmospheric Administration (NOAA), have been looking at measurements and samples of air taken from places like Alert in the Canadian Arctic; Ascension, a UK territory in the South Atlantic; Cape Point, South Africa.

International collaboration leads to new conclusions

The research has been carried out by an international team of atmospheric scientists, led by Euan Nisbet, from Royal Holloway, University of London. Ed Dlugokencky, from the NOAA, Martin Manning from Victoria University, Wellington, New Zealand and a team from the University of Colorado's Institute of Arctic and Alpine Research, led by Jim White, have been working with collaborators from the UK, France, Canada, and South Africa.

Source: University of Royal Holloway London [September 27, 2016]

The traditional diet of Greenland natives — the Inuit — is held up as an example of how high levels of omega-3 fatty acids can counterbalance the bad health effects of a high-fat diet, but a new study hints that what’s true for the Inuit may not be true for everyone else.

The study, which appears in the Sept. 18 issue of the journal Science, shows that the Inuit and their Siberian ancestors have special mutations in genes involved in fat metabolism. The mutations help them partly counteract the effects of a diet high in marine mammal fat, mostly from seals and whales that eat fish with high levels of omega-3 polyunsaturated fatty acids.

Those genetic mutations, found in nearly 100 percent of the Inuit, are found in a mere 2 percent of Europeans and 15 percent of Han Chinese, which means that these groups would synthesize omega-3 polyunsaturated fatty acids differently from the Inuit.

“The original focus on fish oil and omega-3s came from studies of Inuit. On their traditional diet, rich in fat from marine mammals, Inuit seemed quite healthy with a low incidence of cardiovascular disease, so fish oil must be protective,” said project leader Rasmus Nielsen, a UC Berkeley professor of integrative biology. “We’ve now found that they have unique genetic adaptations to this diet, so you cannot extrapolate from them to other populations. A diet that is healthy for the Inuit may not necessarily be good for the rest of us.”

These genetic mutations in the Inuit have more widespread effects. They lower “bad” LDL cholesterol and fasting insulin levels, presumably protecting against cardiovascular disease and diabetes. They also have a significant effect on height, because growth is in part regulated by a person’s fatty acid profile. The researchers found that the mutations causing shorter height in the Inuit are also associated with shorter height in Europeans.

“The mutations we found in the Inuit have profound physiological effects, changing the whole profile of fatty acids in the body, plus it reduces their height by 2 centimeters: nearly an inch,” said Ida Moltke, a University of Copenhagen associate professor of bioinformatics who is joint first author on the study. “Height is controlled by many genes, but this mutation has one of the strongest effects on height ever found by geneticists.”

Personalized diets

Nielsen noted that this is some of the clearest evidence to date that human populations are actually adapted to particular diets; that is, they differ in the way they physiologically respond to diets. Just as genome sequencing can lead to personalized medicine tailored to an individual’s specific set of genes, so too may a person’s genome dictate a personalized diet.

“People ask themselves whether they should be on a Stone Age diet, for example. The response may well depend on their genome,” Nielsen said.

Nielsen and his colleagues at UC Berkeley and in Greenland and Denmark came to their conclusions after analyzing the genomes of 191 Greenlanders with a low admixture of European genes (less than 5 percent) and comparing them to the genomes of 60 Europeans and 44 Han Chinese. They looked for mutations occurring in a large percentage of Inuit individuals but in few or no other groups, which indicates that the mutation spread throughout the Inuit because it was somehow useful to their survival while not essential in other groups.

One cluster of mutations — in genes that code for enzymes that desaturate carbon-carbon bonds in fatty acids — stood out strongly, said Anders Albrechtsen, an associate professor of bioinformatics at the University of Copenhagen and a joint project leader. Fatty acids are the fat in our diet, and occur in saturated, polyunsaturated and unsaturated forms, depending on whether the molecules’ carbon atoms are linked together with no, some or all double bonds. Saturated fats are considered bad because they raise levels of cholesterol in the blood and lower the “good” high-density lipoproteins (HDL), all of which leads to plaque formation and clogged arteries. Diets rich in polyunsaturated and unsaturated fats are linked to lower heart disease. Desaturase enzymes convert dietary fatty acids into fatty acids stored and metabolized by the body.

The mutations common in the Inuit, once known as Eskimos, decrease the production of both omega-3 and omega-6 polyunsaturated fatty acids, presumably to account for the high amount of these fatty acids coming from the diet. Changing production of one fatty acid affects all fatty acids, however, since they regulate one another in a complex way, Albrechtsen said.

Thus, while it’s not clear which specific gene or genes within the cluster is responsible for the alteration in fatty acid metabolism, he said that “when you change the genes that are involved in fatty acid synthesis, you change the whole conversation among fatty acids, and that has a lot of downstream effects.”

Adaptation to Ice Age living

The mutations seem to be at least 20,000 years old, and may have helped many groups of humans adapt to high-meat, high-fat, hunter-gatherer diets from large land and marine mammals high in certain types of omega-3 and omega-6 fatty acids, said Matteo Fumagalli, a researcher at University College London, who is joint first author of the study. They may have arisen among the original Siberians, who have lived in the Arctic for more than 20,000 years and arrived in Greenland when Inuit settled there about 1,000 years ago.

“We think it is a quite old selection that may have helped humans adapt to the environment during the last Ice Age, but the selection is far stronger in the Inuit than anywhere else,” said Fumagalli. “It’s fascinating that Greenlanders have a unique genetic makeup that lets them better use their traditional food sources.”

The researchers discovered another common mutation in a gene that is involved in the differentiation of brown, subcutaneous fat cells and brite fat cells, the latter of which generate heat. This may also have helped the Inuit adapt to a cold environment.

Author: Robert Sanders | Source: University of California, Berkeley [September 18, 2015]

Killer whales in European waters face extinction due to outlawed but long-lived pollutants that also threaten several species of dolphins, according a study published in the journal >Scientific Reports.

Toxic chemicals known by the acronym PCBs are poisoning these marine mammals, and in some cases severely impeding their ability to reproduce, researchers reported.

Becoming more concentrated as they move up the food chain, PCBs settle into the fatty tissue of top ocean predators.

The deadly compounds—used in manufacturing and construction and banned across the European Union in 1987—can also be passed on to orca and dolphin calves suckling their mothers' milk.

"Few coastal orca populations remain in western European waters," said lead author Paul Jepson of the Zoological Society of London, noting that those in the Mediterranean and North Sea have already disappeared.

"The ones that do persist are very small and suffering low or zero rates of reproduction."

A community of 36 orcas, or killer whales, off the coast of Portugal—observed by scientists for decades—has not produced any offspring in more than ten years, the study reported.

An even smaller grouping near Scotland "will go extinct," Jepson told journalists by phone.

The death of a female known as Lulu, whose carcass was discovered on the Scottish island of Tiree last week, reduced this pod from nine to eight.

As well as direct observation, biopsies of individuals in the wild have also shown that these orca populations are not reproducing.

When female killer whales give birth, they transfer about 90 percent of the PCBs accumulated in their bodies—sometimes over decades—to their calves, purging themselves but poisoning their offspring.

Recent biopsies, however, revealed that all the females have the same level of PCB toxins in their system as males, evidence that they had not produced calves in the preceding years.

The toxic effect of PCBs on marine mammals was known, but this is the first overview—based on tissue samples from more than 1,000 stranded and biopsied whales, dolphins and orcas—of the extent of the damage.

Climbing the food chain

PCBs were widely used in manufacturing electrical equipment, paints and flame retardants. Designed to withstand weathering, they were also added to sealants used in buildings.

Europe produced some 300,000 tonnes of the compound from 1954 to 1984, and 90 percent of it has yet to be destroyed or safely stored away.

PCBs—which do not dissolve in water—reach the ocean via several routes.

"It is leaching from landfills into rivers and estuaries, and eventually into the marine environment," Jepson explained.

Sediment dredging to a depth of ten metres (30 feet) along shipping lanes in industrial ports brings the deadly chemicals to the surface.

From there, they gradually climb the food chain, becoming more toxic along the way: from bottom-feeding mollusks to crabs to small fish to the bigger fish eaten by orcas, dolphins and porpoises.

Further north, a healthier population of several thousand orcas living in waters near Iceland and northern Norway provide additional evidence that PCBs are, in fact, causing the decline of their cousins to the south.

Whereas the southern killer whales eat large fish and mammals, such as seals, the Arctic orcas subsist almost exclusively on herring.

Because herring eat plankton, they are outside the food chain along which PCBs climb, explaining why the northern orcas have ten times less PCB in their fatty tissue.

Disposing of land-based PCBs—made to resist heat, chemical attack and degradation—is difficult, Jepson said.

"They were designed to last a very long time, so it is incredibly hard to destroy them."

Author: Marlowe Hood | Source: AFP [Janaury 14, 2016]

The arrival of intense cold similar to the one raged during the “Little Ice Age”, which froze the world during the XVII century and in the beginning of the XVIII century, is expected in the years 2030–2040.

These conclusions were presented by Prof. V. Zharkova (Northumbria University) during the National Astronomy Meeting in Llandudno in Wales by the international group of scientists, which also includes Dr Helen Popova of the Skobeltsyn Institute of Nuclear Physics and of the Faculty of Physics of the Lomonosov Moscow State University, professor Simon Shepherd of Bradford University (UK) and Dr Sergei Zharkov of Hull University (UK).

It is known, that the Sun has its own magnetic field, the amplitude and spatial configuration of which vary with time. The formation and decay of strong magnetic fields in the solar atmosphere results in the changes of electromagnetic radiation from the Sun, of the intensity of plasma flows coming from the Sun, and the number of sunspots on the Sun’s surface. The study of changes in the number of sunspots on the Sun’s surface has a cyclic structure vary in every 11 years that is also imposed on the Earth environment as the analysis of carbon-14, beryllium-10 and other isotopes in glaciers and in the trees showed.

There are several cycles with different periods and properties, while the 11-year cycle, the 90-year cycle are the best known of them. The 11-year cycle appears as a cyclical reduction in stains on the surface of the Sun every 11 years. Its 90-year variation is associated with periodic reduction in the number of spots in the 11-year cycle in the 50-25%. In 17th century though there was a prolonged of the solar activity called the Maunder minimum, which lasted roughly from 1645 to 1700. During this period, there were only about 50 sunspots instead of the usual 40-50 thousand sunspots. Analysis of solar radiation showed that its maxima and minima almost coincide with the maxima and minima in the number of spots.

In the current study published in 3 peer-reviewed papers the researchers analyzed a total background magnetic field from full disk magnetograms for three cycles of solar activity (21-23) by applying the so-called “principal component analysis”, which allows to reduce the data dimensionality and noise and to identify waves with the largest contribution to the observational data. This method can be compared with the decomposition of white light on the rainbow prism detecting the waves of different frequencies. As a result, the researchers developed a new method of analysis, which helped to uncover, that the magnetic waves in the Sun are generated in pairs, with the main pair covering 40% of variance of the data (Zharkova et al, 2012, MNRAS). The principal component pair is responsible for the variations of a dipole field of the Sun, which is changing its polarity from pole to pole during 11 year solar activity.

The magnetic waves travel from the opposite hemisphere to the Northern hemisphere (odd cycles) or to Southern hemisphere (even cycles), with the phase shift between the waves increasing with a cycle number. The waves interacts with each other in the hemisphere where they have maximum (Northern for odd cycles and Southern for even ones). These two components are assumed to originate in two different layers in the solar interior (inner and outer) with close, but not equal, frequencies and a variable phase shift (Popova et al, 2013, AnnGeo).

The scientists managed to derive the analytical formula, describing the evolution of these two waves and calculated the summary curve which was linked to the variations of sunspot numbers, the original proxy of solar activity, if one used the modulus of the summary curve (Shepherd et al, 2014, ApJ). By using this formula the scientists made first the prediction of magnetic activity in the cycle 24, which gave 97% accuracy in comparison with the principal components derived from the observations.

Inspired by this success, the authors extended the prediction of these two magnetic waves to the next two cycle 25 and 26 and discovered that the waves become fully separated into the opposite hemispheres in cycle 26 and thus have little chance of interacting and producing sunspot numbers. This will lead to a sharp decline in solar activity in years 2030 – 2040 comparable with the conditions existed previously during the Maunder minimum in the XVII century when there were only about 50-70 sunspots observed instead of the usual 40-50 thousand expected.

The new reduction of the solar activity will lead to reduction of the solar irradiance by 3W/m^2 according to Lean (1997). This resulted in significant cooling of Earth and very severe winters and cold summers. “Several studies have shown that the Maunder Minimum coincided with the coldest phase of global cooling, which was called “the Little Ice Age”. During this period there were very cold winters in Europe and North America. In the days of the Maunder minimum the water in the river Thames and the Danube River froze, the Moscow River was covered by ice every six months, snow lay on some plains year round and Greenland was covered by glaciers” – says Dr Helen Popova, who developed a unique physical-mathematical model of the evolution of the magnetic activity of the sun and used it to gain the patterns of occurrence of global minima of solar activity and gave them a physical interpretation.

If the similar reduction will be observed during the upcoming Maunder minimum this can lead to the similar cooling of the Earth atmosphere. According to Dr Helen Popova, if the existing theories about the impact of solar activity on the climate are true, then this minimum will lead to a significant cooling, similar to the one occurred during the Maunder minimum.

However, only the time will show soon enough (within the next 5-15 years) if this will happen.

“Given that our future minimum will last for at least three solar cycles, which is about 30 years, it is possible, that the lowering of the temperature will not be as deep as during the Maunder minimum. But we will have to examine it in detail. We keep in touch with climatologists from different countries. We plan to work in this direction”, — Dr Helen Popova said.

The notion that solar activity affects the climate, appeared long ago. It is known, for example, that a change in the total quantity of the electromagnetic radiation by only 1% can result in a noticeable change in the temperature distribution and air flow all over the Earth. Ultraviolet rays cause photochemical effect, which leads to the formation of ozone at the altitude of 30-40 km. The flow of ultraviolet rays increases sharply during chromospheric flares in the Sun. Ozone, which absorbs the sun’s rays well enough, is being heated and it affects the air currents in the lower layers of the atmosphere and, consequently, the weather. Powerful emission of corpuscles, which can reach the Earth’s surface, arise periodically during the high solar activity. They can move in complex trajectories, causing aurorae, geomagnetic storms and disturbances of radio communication.

By increasing the flow of particles in the lower atmospheric layers air flows of meridional direction enhance: warm currents from the south with even greater energy rush in the high latitudes and cold currents, carrying arctic air, penetrate deeper into the south. In addition, the solar activity affects the intensity of fluxes of galactic cosmic rays. The minimum activity streams become more intense, which also affects the chemical processes in the Earth’s atmosphere

The study of deuterium in the Antarctic showed that there were five global warmings and four Ice Ages for the past 400 thousand years. The increase in the volcanic activity comes after the Ice Age and it leads to the greenhouse gas emissions. The magnetic field of the Sun grows, what means that the flux of cosmic rays decreases, increasing the number of clouds and leading to the warming again. Next comes the reverse process, where the magnetic field of the Sun decreases, the intensity of cosmic ray rises, reducing the clouds and making the atmosphere cool again. This process comes with some delay.

Dr Helen Popova responds cautiously, while speaking about the human influence on climate.

“There is no strong evidence, that global warming is caused by human activity. The study of deuterium in the Antarctic showed that there were five global warmings and four Ice Ages for the past 400 thousand years. People first appeared on the Earth about 60 thousand years ago. However, even if human activities influence the climate, we can say, that the Sun with the new minimum gives humanity more time or a second chance to reduce their industrial emissions and to prepare, when the Sun will return to normal activity”, — Dr Helen Popova summarized.

Source: Lomonosov Moscow State University [July 17, 2015]