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News Article | December 14, 2016
Site: www.eurekalert.org

CORVALLIS, Ore. - A sound in the Mariana Trench notable for its complexity and wide frequency range likely represents the discovery of a new baleen whale call, according to the Oregon State University researchers who recorded and analyzed it. Scientists at OSU's Hatfield Marine Science Center named it the "Western Pacific Biotwang." Lasting between 2.5 and 3.5 seconds, the five-part call includes deep moans at frequencies as low as 38 hertz and a metallic finale that pushes as high as 8,000 hertz. "It's very distinct, with all these crazy parts," said Sharon Nieukirk, senior faculty research assistant in marine bioacoustics at Oregon State. "The low-frequency moaning part is typical of baleen whales, and it's that kind of twangy sound that makes it really unique. We don't find many new baleen whale calls." Recorded via passive acoustic ocean gliders, which are instruments that can travel autonomously for months at a time and dive up to 1,000 meters, the Western Pacific Biotwang most closely resembles the so-called "Star Wars" sound produced by dwarf minke whales on the Great Barrier Reef off the northeast coast of Australia, researchers say. The Mariana Trench, the deepest known part of the Earth's oceans, lies between Japan to the north and Australia to the south and features depths in excess of 36,000 feet. Minke whales are baleen whales - meaning they feed by using baleen plates in their mouths to filter krill and small fish from seawater - and live in most oceans. They produce a collection of regionally specific calls, which in addition to the Star Wars call include "boings" in the North Pacific and low-frequency pulse trains in the Atlantic. "We don't really know that much about minke whale distribution at low latitudes," said Nieukirk, lead author on the study whose results were recently published in the Journal of the Acoustical Society of America. "The species is the smallest of the baleen whales, doesn't spend much time at the surface, has an inconspicuous blow, and often lives in areas where high seas make sighting difficult. But they call frequently, making them good candidates for acoustic studies." Nieukirk said the Western Pacific Biotwang has enough similarities to the Star Wars call - complex structure, frequency sweep and metallic conclusion - that it's reasonable to think a minke whale is responsible for it. But scientists can't yet be sure, and many other questions remain. For example, baleen whale calls are often related to mating and heard mainly during the winter, yet the Western Pacific Biotwang was recorded throughout the year. "If it's a mating call, why are we getting it year round? That's a mystery," said Nieukirk, part of the team at the Cooperative Institute for Marine Resources Studies, a partnership between OSU and the NOAA Pacific Marine Environmental Laboratory. "We need to determine how often the call occurs in summer versus winter, and how widely this call is really distributed." The call is tricky to find when combing through recorded sound data, Nieukirk explains, because of its huge frequency range. Typically acoustic scientists zero in on narrower frequency ranges when analyzing ocean recordings, and in this case that would mean not detecting portions of the Western Pacific Biotwang. "Now that we've published these data, we hope researchers can identify this call in past and future data, and ultimately we should be able to pin down the source of the sound," Nieukirk said. "More data are needed, including genetic, acoustic and visual identification of the source, to confirm the species and gain insight into how this sound is being used. Our hope is to mount an expedition to go out and do acoustic localization, find the animals, get biopsy samples and find out exactly what's making the sound. It really is an amazing, weird sound, and good science will explain it."


Scientists at OSU's Hatfield Marine Science Center named it the "Western Pacific Biotwang." Lasting between 2.5 and 3.5 seconds, the five-part call includes deep moans at frequencies as low as 38 hertz and a metallic finale that pushes as high as 8,000 hertz. "It's very distinct, with all these crazy parts," said Sharon Nieukirk, senior faculty research assistant in marine bioacoustics at Oregon State. "The low-frequency moaning part is typical of baleen whales, and it's that kind of twangy sound that makes it really unique. We don't find many new baleen whale calls." Recorded via passive acoustic ocean gliders, which are instruments that can travel autonomously for months at a time and dive up to 1,000 meters, the Western Pacific Biotwang most closely resembles the so-called "Star Wars" sound produced by dwarf minke whales on the Great Barrier Reef off the northeast coast of Australia, researchers say. The Mariana Trench, the deepest known part of the Earth's oceans, lies between Japan to the north and Australia to the south and features depths in excess of 36,000 feet. Minke whales are baleen whales - meaning they feed by using baleen plates in their mouths to filter krill and small fish from seawater - and live in most oceans. They produce a collection of regionally specific calls, which in addition to the Star Wars call include "boings" in the North Pacific and low-frequency pulse trains in the Atlantic. "We don't really know that much about minke whale distribution at low latitudes," said Nieukirk, lead author on the study whose results were recently published in the Journal of the Acoustical Society of America. "The species is the smallest of the baleen whales, doesn't spend much time at the surface, has an inconspicuous blow, and often lives in areas where high seas make sighting difficult. But they call frequently, making them good candidates for acoustic studies." Nieukirk said the Western Pacific Biotwang has enough similarities to the Star Wars call - complex structure, frequency sweep and metallic conclusion - that it's reasonable to think a minke whale is responsible for it. But scientists can't yet be sure, and many other questions remain. For example, baleen whale calls are often related to mating and heard mainly during the winter, yet the Western Pacific Biotwang was recorded throughout the year. "If it's a mating call, why are we getting it year round? That's a mystery," said Nieukirk, part of the team at the Cooperative Institute for Marine Resources Studies, a partnership between OSU and the NOAA Pacific Marine Environmental Laboratory. "We need to determine how often the call occurs in summer versus winter, and how widely this call is really distributed." The call is tricky to find when combing through recorded sound data, Nieukirk explains, because of its huge frequency range. Typically acoustic scientists zero in on narrower frequency ranges when analyzing ocean recordings, and in this case that would mean not detecting portions of the Western Pacific Biotwang. "Now that we've published these data, we hope researchers can identify this call in past and future data, and ultimately we should be able to pin down the source of the sound," Nieukirk said. "More data are needed, including genetic, acoustic and visual identification of the source, to confirm the species and gain insight into how this sound is being used. Our hope is to mount an expedition to go out and do acoustic localization, find the animals, get biopsy samples and find out exactly what's making the sound. It really is an amazing, weird sound, and good science will explain it." Explore further: Passive acoustic monitoring reveals clues to minke whale calling behavior and movements More information: Sharon L. Nieukirk et al, A complex baleen whale call recorded in the Mariana Trench Marine National Monument, The Journal of the Acoustical Society of America (2016). DOI: 10.1121/1.4962377


News Article | February 15, 2017
Site: www.nature.com

As the Arctic slipped into the half-darkness of autumn last year, it seemed to enter the Twilight Zone. In the span of a few months, all manner of strange things happened. The cap of sea ice covering the Arctic Ocean started to shrink when it should have been growing. Temperatures at the North Pole soared more than 20 °C above normal at times. And polar bears prowling the shorelines of Hudson Bay had a record number of run-ins with people while waiting for the water to freeze over. It was a stark illustration of just how quickly climate change is reshaping the far north. And if last autumn was bizarre, it's the summers that have really got scientists worried. As early as 2030, researchers say, the Arctic Ocean could lose essentially all of its ice during the warmest months of the year — a radical transformation that would upend Arctic ecosystems and disrupt many northern communities. Change will spill beyond the region, too. An increasingly blue Arctic Ocean could amplify warming trends and even scramble weather patterns around the globe. “It’s not just that we’re talking about polar bears or seals,” says Julienne Stroeve, a sea-ice researcher at University College London. “We all are ice-dependent species.” With the prospect of ice-free Arctic summers on the horizon, scientists are striving to understand how residents of the north will fare, which animals face the biggest risks and whether nations could save them by protecting small icy refuges. But as some researchers look even further into the future, they see reasons to preserve hope. If society ever manages to reverse the surge in greenhouse-gas concentrations — as some suspect it ultimately will — then the same physics that makes it easy for Arctic sea ice to melt rapidly may also allow it to regrow, says Stephanie Pfirman, a sea-ice researcher at Barnard College in New York City. She and other scientists say that it’s time to look beyond the Arctic’s decline and start thinking about what it would take to restore sea ice. That raises controversial questions about how quickly summer ice could return and whether it could regrow fast enough to spare Arctic species. Could nations even cool the climate quickly through geoengineering, to reverse the most drastic changes up north? Pfirman and her colleagues published a paper1 last year designed to kick-start a broader conversation about how countries might plan for the regrowth of ice, and whether they would welcome it. Only by considering all the possibilities for the far future can the world stay one step ahead of the ever-changing Arctic, say scientists. “We’ve committed to the Arctic of the next generation,” Pfirman says. “What comes next?” Pfirman remembers the first time she realized just how fast the Arctic was unravelling. It was September 2007, and she was preparing to give a talk. She went online to download the latest sea-ice maps and discovered something disturbing: the extent of Arctic ice had shrunk past the record minimum and was still dropping. “Oh, no! It’s happening,” she thought. Although Pfirman and others knew that Arctic sea ice was shrinking, they hadn’t expected to see such extreme ice losses until the middle of the twenty-first century. “It was a wake-up call that we had basically run out of time,” she says. In theory, there’s still a chance that the world could prevent the total loss of summer sea ice. Global climate models suggest that about 3 million square kilometres — roughly half of the minimum summer coverage in recent decades — could survive if countries fulfil their commitments to the newly ratified Paris climate agreement, which limits global warming to 2 °C above pre-industrial temperatures. But sea-ice researchers aren’t counting on that. Models have consistently underestimated ice losses in the past, causing scientists to worry that the declines in the next few decades will outpace projections2. And given the limited commitments that countries have made so far to address climate change, many researchers suspect the world will overshoot the 2 °C target, all but guaranteeing essentially ice-free summers (winter ice is projected to persist for much longer). In the best-case scenario, the Arctic is in for a 4–5 °C temperature rise, thanks to processes that amplify warming at high latitudes, says James Overland, an oceanographer at the US National Oceanic and Atmospheric Administration in Seattle, Washington. “We really don’t have any clue about how disruptive that’s going to be.” The Arctic’s 4 million residents — including 400,000 indigenous people — will feel the most direct effects of ice loss. Entire coastal communities, such as many in Alaska, will be forced to relocate as permafrost melts and shorelines crumble without sea ice to buffer them from violent storms, according to a 2013 report3 by the Brookings Institution in Washington DC. Residents in Greenland will find it hard to travel on sea ice, and reindeer herders in Siberia could struggle to feed their animals. At the same time, new economic opportunities will beckon as open water allows greater access to fishing grounds, oil and gas deposits, and other sources of revenue. People living at mid-latitudes may not be immune, either. Emerging research4 suggests that open water in the Arctic might have helped to amplify weather events, such as cold snaps in the United States, Europe and Asia in recent winters. Indeed, the impacts could reach around the globe. That’s because sea ice helps to cool the planet by reflecting sunlight and preventing the Arctic Ocean from absorbing heat. Keeping local air and water temperatures low, in turn, limits melting of the Greenland ice sheet and permafrost. With summer ice gone, Greenland’s glaciers could contribute more to sea-level rise, and permafrost could release its stores of greenhouse gases such as methane. Such is the vast influence of Arctic ice. “It is really the tail that wags the dog of global climate,” says Brenda Ekwurzel, director of climate science at the Union of Concerned Scientists in Cambridge, Massachusetts. But Arctic ecosystems will take the biggest hit. In 2007, for example, biologists in Alaska noticed something odd: vast numbers of walruses had clambered ashore on the coast of the Chukchi Sea. From above, it looked like the Woodstock music festival — with tusks — as thousands of plump pinnipeds crowded swathes of ice-free shoreline. Normally, walruses rest atop sea ice while foraging on the shallow sea floor. But that year, and almost every year since, sea-ice retreat made that impossible by late summer. Pacific walruses have adapted by hauling out on land, but scientists with the US Fish and Wildlife Service worry that their numbers will continue to decline. Here and across the region, the effects of Arctic thawing will ripple through ecosystems. In the ocean, photosynthetic plankton that thrive in open water will replace algae that grow on ice. Some models5 suggest that biological productivity in a seasonally ice-free Arctic could increase by up to 70% by 2100, which could boost revenue from Arctic fisheries even more. (To prevent a seafood gold rush, five Arctic nations have agreed to refrain from unregulated fishing in international waters for now.) Many whales already seem to be benefiting from the bounty of food, says Sue Moore, an Arctic mammal specialist at the Pacific Marine Environmental Laboratory. But the changing Arctic will pose a challenge for species whose life cycles are intimately linked to sea ice, such as walruses and Arctic seals — as well as polar bears, which don’t have much to eat on land. Research6 suggests that many will starve if the ice-free season gets too long in much of the Arctic. “Basically, you can write off most of the southern populations,” says Andrew Derocher, a biologist at the University of Alberta in Edmonton, Canada. Such findings spurred the US Fish and Wildlife Service to list polar bears as threatened in 2008. Ice-dependent ecosystems may survive for longest along the rugged north shores of Greenland and Canada, where models suggest that about half a million square kilometres of summer sea ice will linger after the rest of the Arctic opens up (see ‘Going, going …’). Wind patterns cause ice to pile up there, and the thickness of the ice — along with the high latitude — helps prevent it from melting. “The Siberian coastlines are the ice factory, and the Canadian Arctic Archipelago is the ice graveyard,” says Robert Newton, an oceanographer at Columbia University’s Lamont–Doherty Earth Observatory in Palisades, New York. Groups such as the wildlife charity WWF have proposed protecting this ‘last ice area’ as a World Heritage Site in the hope that it will serve as a life preserver for many Arctic species. Last December, Canada announced that it would at least consider setting the area aside for conservation, and indigenous groups have expressed interest in helping to manage it. (Before he left office, then-US president Barack Obama joined Canadian Prime Minister Justin Trudeau in pledging to protect 17% of the countries’ Arctic lands and 10% of marine areas by 2020.) But the last ice area has limitations as an Arctic Noah’s ark. Some species don’t live in the region, and those that do are there in only small numbers. Derocher estimates that there are less than 2,000 polar bears in that last ice area today — a fraction of the total Arctic population of roughly 25,000. How many bears will live there in the future depends on how the ecosystem evolves with warming. The area may also be more vulnerable than global climate models suggest. Bruno Tremblay, a sea-ice researcher at McGill University in Montreal, Canada, and David Huard, an independent climate consultant based in Quebec, Canada, studied the fate of the refuge with a high-resolution sea-ice and ocean model that better represented the narrow channels between the islands of the Canadian archipelago. In a report7 commissioned by the WWF, they found that ice might actually be able to sneak between the islands and flow south to latitudes where it would melt. According to the model, Tremblay says, “even the last ice area gets flushed out much more efficiently”. If the future of the Arctic seems dire, there is one source of optimism: summer sea ice will return whenever the planet cools down again. “It’s not this irreversible process,” Stroeve says. “You could bring it back even if you lose it all.” Unlike land-based ice sheets, which wax and wane over millennia and lag behind climate changes by similar spans, sea ice will regrow as soon as summer temperatures get cold enough. But identifying the exact threshold at which sea ice will return is tricky, says Dirk Notz, a sea-ice researcher at the Max Planck Institute for Meteorology in Hamburg, Germany. On the basis of model projections, researchers suggest that the threshold hovers around 450 parts per million (p.p.m.) — some 50 p.p.m. higher than today. But greenhouse-gas concentrations are not the only factor that affects ice regrowth; it also depends on how long the region has been ice-free in summer, which determines how much heat can build up in the Arctic Ocean. Notz and his colleagues studied the interplay between greenhouse gases and ocean temperature with a global climate model8. They increased CO from pre-industrial concentrations of 280 p.p.m. to 1,100 p.p.m. — a bit more than the 1,000 p.p.m. projected by 2100 if no major action is taken to curtail greenhouse-gas emissions. Then they left it at those levels for millennia. This obliterated both winter and summer sea ice, and allowed the ocean to warm up. The researchers then reduced CO concentrations to levels at which summer ice should have returned, but it did not regrow until the ocean had a chance to cool off, which took centuries. By contrast, if the Arctic experiences ice-free summers for a relatively short time before greenhouse gases drop, then models suggest ice would regrow much sooner. That could theoretically start to happen by the end of the century, assuming that nations take very aggressive steps to reduce carbon dioxide levels1, according to Newton, Pfirman and their colleagues. So even if society cannot forestall the loss of summer sea ice in coming decades, taking action to keep CO concentrations under control could still make it easier to regrow the ice cover later, Notz says. Given the stakes, some researchers have proposed global-scale geoengineering to cool the planet and, by extension, preserve or restore ice. Others argue that it might be possible to chill just the north, for instance by artificially whitening the Arctic Ocean with light-coloured floating particles to reflect sunlight. A study9 this year suggested installing wind-powered pumps to bring water to the surface in winter, where it would freeze, forming thicker ice. But many researchers hesitate to embrace geoengineering. And most agree that regional efforts would take tremendous effort and have limited benefits, given that Earth’s circulation systems could just bring more heat north to compensate. “It’s kind of like walking against a conveyor the wrong way,” Pfirman says. She and others agree that managing greenhouse gases — and local pollutants such as black carbon from shipping — is the only long-term solution. Returning to a world with summer sea ice could have big perks, such as restoring some of the climate services that the Arctic provides to the globe and stabilizing weather patterns. And in the region itself, restoring a white Arctic could offer relief to polar bears and other ice-dependent species, says Pfirman. These creatures might be able to weather a relatively short ice-free window, hunkered down in either the last ice area or other places set aside to preserve biodiversity. When the ice returned, they could spread out again to repopulate the Arctic. That has almost certainly happened during past climate changes. For instance, researchers think the Arctic may have experienced nearly ice-free summers during the last interglacial period, 130,000 years ago10. But, one thing is certain: getting back to a world with Arctic summer sea ice won’t be simple, politically or technically. Not everyone will embrace a return to an ice-covered Arctic, especially if it’s been blue for several generations. Companies and countries are already eyeing the opportunities for oil and gas exploration, mining, shipping, tourism and fishing in a region hungry for economic development. “In many communities, people are split,” Pfirman says. Some researchers also say that the idea of regrowing sea ice seems like wishful thinking, because it would require efforts well beyond what nations must do to meet the Paris agreement. Limiting warming to 2 °C will probably entail converting huge swathes of land into forest and using still-nascent technologies to suck billions of tonnes of CO out of the air. Lowering greenhouse-gas concentrations enough to regrow ice would demand even more. And if summer sea ice ever does come back, it’s hard to know how a remade Arctic would work, Derocher says. “There will be an ecosystem. It will function. It just may not look like the one we currently have.”


News Article | November 3, 2016
Site: www.csmonitor.com

Climate scientists have calculated just how fast humans' carbon emissions are melting Arctic sea ice in a new study. Just 75 miles in a fossil-fuel powered car equals one square foot of ice melted Arctic ice. No more watching videos at work: Facebook will now default to audio Sorry polar bears, the Arctic Ocean might be free of sea ice before 2050. According to new calculations, for every metric ton of carbon dioxide emitted, about three square meters (approximately 32.3 square feet) of Arctic summer sea ice disappears. And, with humans currently emitting about 35 to 40 million tons of CO2 each year, the future doesn't look very frozen. It's not hard to rack up those emissions. About 2,433 miles of driving – roughly the distance from Washington, DC to Las Vegas – or just one seat on a return flight from New York to London – on average produces a metric ton of CO2 emissions. Or, for those who aren't long-distance travelers, just over 75 miles of driving in a typical fossil-fuel powered car produces enough emissions to melt one square foot of ice. That's according to Dirk Notz, head of a research group at the Max Planck Institute for Meteorology in Germany that studies sea ice. Dr. Notz calculated the relationship between CO2 emissions and the loss of Arctic summer sea ice as lead author of a paper published Thursday in the journal Science. "Our study now provides individuals with the sense that their own individual actions make a difference," Notz tells The Christian Science Monitor in a phone interview. "If I decide to drive my car a little less or to buy a car that uses less fuel, for example, all these little actions will make a difference for sea ice." Technically, Notz has calculated when there will be less than 1 million square kilometers (386,000 square miles) of Arctic sea ice left in September, after summer melting, a measurement commonly used to define sea ice free conditions. Winter temperatures will continue to freeze parts of the Arctic Ocean. That 1 million square kilometers "seems like quite a lot of ice," says Walter Meier, a sea ice researcher at the NASA Goddard Space Flight Center who was not part of the study. "But in reality it's not that much." "The Arctic Ocean will be for all intents and purposes a blue Arctic Ocean" when that happens, he says. Dr. Meier says Notz's calculations oversimplify the relationship between carbon emissions and Arctic sea ice loss. "The climate system is, in reality, a lot more complex than that," he says in a phone interview with the Monitor. Kevin Trenberth of the the Climate Analysis Section at the National Center for Atmospheric Research, who also was not part of the research, agrees. "I think it's too simple because it doesn't deal with ocean transports and it doesn't deal with atmospheric transports," he says in a phone interview with the Monitor. Furthermore, Dr. Trenberth says, seasonal variations complicate trends so the calculated relationship between CO2 and sea ice loss could be off. Although he questions their methods, Trenberth agrees with the researchers that the Arctic will see an ice-free September. And, he says, it could be as soon as in the 2030s. What would a world with a blue Arctic look like? "We're changing ice that has been around for many years to, mostly, ice that forms every year," James Overland, an oceanographer at the NOAA Pacific Marine Environmental Laboratory who was not part of the study, tells the Monitor in a phone interview. In decades past, ice would build up and become thicker through the winter. While some of that ice would melt during the summer, most would remain to accumulate more ice year after year. Animals like polar bears and walruses use those thicker sheets of ice as a sort of home base when hunting. Thinner and more fragmented ice could destroy their lifestyles. And that's not just true for animals; a disrupted icy ecosystem could make it more difficult for native human populations to hunt and forage too. But loss of Arctic sea ice probably won't just have a local impact. "Arctic sea ice regulates the temperature of our planet by cooling the Atlantic and Pacific waters," David Barber, a sea ice and climate scientist at the University of Manitoba, who was not involved in the research, writes in an email to the Monitor. Some research has suggested that less Arctic ice could lead to a weakening of the jet stream, an atmospheric system that affects the global climate. This shift could be leading to more extreme weather events, like flooding, freezing, and even droughts, already. And on top of that, Arctic sea ice serves as a sort of refrigerator for the planet, Notz explains. When the summer sun rays hit the vast, bright ice, much of that energy is reflected back. But the dark waters of a blue ocean will absorb that heat, leading to even more warming and melting. Then, warmer, more wave-filled waters can eat away at other geological features, including glaciers, coastlines, and permafrost, in a spiral of changes. It is important to note, however, that melting Arctic sea ice will not directly raise sea levels. Like melting ice in a soda glass, the oceans won't spill over from ice that is already floating in water. But as ice on land, such as the Greenland ice sheet, melts as an indirect effect of the disappearing sea ice, that water will flow into the oceans and raise sea levels. The Paris climate agreement is set to go into effect Friday with the aim of meeting an ambitious goal: preventing global temperatures from rising 2 degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial levels. But, by Notz's calculations, Arctic summer sea ice will already be gone if temperatures reach that threshold. That sea ice could survive, however, if the more aggressive target of 1.5 degrees Celsius warming is attained. Further complicating things, the Arctic is heating up faster than the rest of the world, perhaps two or three times faster, Notz says. Trenberth points out that greenhouse gas emissions can also have a delayed effect. So even if humans suddenly stopped emitting carbon altogether, temperatures likely still would rise. And, he says, although scientists have been discussing ways to extract CO2 from the atmosphere, "this is an extremely difficult thing to really achieve." Looking at the sea ice loss in the Arctic is "a really stark indicator of climate change," Meier says. "We think of the Arctic as a cold place, but in a lot of ways it's relatively warm," he says. During the summer, many sections sit on the cusp of the freezing point. So, while the difference between 80 and 82 degrees Fahrenheit might not make a huge difference in Washington D.C., Meier explains, if you go from 31 to 33 degrees in the Arctic, it's the difference between ice skating and swimming. While this study doesn't really add new information for scientists, Meier says, with Arctic sea ice far from most people's everyday lives and carbon emissions, "it really helps people understand and visualize the impact."


News Article | November 3, 2016
Site: www.csmonitor.com

Climate scientists have calculated just how fast humans' carbon emissions are melting Arctic sea ice in a new study. Just 75 miles in a fossil-fuel powered car equals one square foot of ice melted Arctic ice. No more watching videos at work: Facebook will now default to audio Sorry polar bears, the Arctic Ocean might be free of sea ice before 2050. According to new calculations, for every metric ton of carbon dioxide emitted, about three square meters (approximately 32.3 square feet) of Arctic summer sea ice disappears. And, with humans currently emitting about 35 to 40 million tons of CO2 each year, the future doesn't look very frozen. It's not hard to rack up those emissions. About 2,433 miles of driving – roughly the distance from Washington, DC to Las Vegas – or just one seat on a return flight from New York to London – on average produces a metric ton of CO2 emissions. Or, for those who aren't long-distance travelers, just over 75 miles of driving in a typical fossil-fuel powered car produces enough emissions to melt one square foot of ice. That's according to Dirk Notz, head of a research group at the Max Planck Institute for Meteorology in Germany that studies sea ice. Dr. Notz calculated the relationship between CO2 emissions and the loss of Arctic summer sea ice as lead author of a paper published Thursday in the journal Science. "Our study now provides individuals with the sense that their own individual actions make a difference," Notz tells The Christian Science Monitor in a phone interview. "If I decide to drive my car a little less or to buy a car that uses less fuel, for example, all these little actions will make a difference for sea ice." Technically, Notz has calculated when there will be less than 1 million square kilometers (386,000 square miles) of Arctic sea ice left in September, after summer melting, a measurement commonly used to define sea ice free conditions. Winter temperatures will continue to freeze parts of the Arctic Ocean. That 1 million square kilometers "seems like quite a lot of ice," says Walter Meier, a sea ice researcher at the NASA Goddard Space Flight Center who was not part of the study. "But in reality it's not that much." "The Arctic Ocean will be for all intents and purposes a blue Arctic Ocean" when that happens, he says. Dr. Meier says Notz's calculations oversimplify the relationship between carbon emissions and Arctic sea ice loss. "The climate system is, in reality, a lot more complex than that," he says in a phone interview with the Monitor. Kevin Trenberth of the the Climate Analysis Section at the National Center for Atmospheric Research, who also was not part of the research, agrees. "I think it's too simple because it doesn't deal with ocean transports and it doesn't deal with atmospheric transports," he says in a phone interview with the Monitor. Furthermore, Dr. Trenberth says, seasonal variations complicate trends so the calculated relationship between CO2 and sea ice loss could be off. Although he questions their methods, Trenberth agrees with the researchers that the Arctic will see an ice-free September. And, he says, it could be as soon as in the 2030s. What would a world with a blue Arctic look like? "We're changing ice that has been around for many years to, mostly, ice that forms every year," James Overland, an oceanographer at the NOAA Pacific Marine Environmental Laboratory who was not part of the study, tells the Monitor in a phone interview. In decades past, ice would build up and become thicker through the winter. While some of that ice would melt during the summer, most would remain to accumulate more ice year after year. Animals like polar bears and walruses use those thicker sheets of ice as a sort of home base when hunting. Thinner and more fragmented ice could destroy their lifestyles. And that's not just true for animals; a disrupted icy ecosystem could make it more difficult for native human populations to hunt and forage too. But loss of Arctic sea ice probably won't just have a local impact. "Arctic sea ice regulates the temperature of our planet by cooling the Atlantic and Pacific waters," David Barber, a sea ice and climate scientist at the University of Manitoba, who was not involved in the research, writes in an email to the Monitor. Some research has suggested that less Arctic ice could lead to a weakening of the jet stream, an atmospheric system that affects the global climate. This shift could be leading to more extreme weather events, like flooding, freezing, and even droughts, already. And on top of that, Arctic sea ice serves as a sort of refrigerator for the planet, Notz explains. When the summer sun rays hit the vast, bright ice, much of that energy is reflected back. But the dark waters of a blue ocean will absorb that heat, leading to even more warming and melting. Then, warmer, more wave-filled waters can eat away at other geological features, including glaciers, coastlines, and permafrost, in a spiral of changes. It is important to note, however, that melting Arctic sea ice will not directly raise sea levels. Like melting ice in a soda glass, the oceans won't spill over from ice that is already floating in water. But as ice on land, such as the Greenland ice sheet, melts as an indirect effect of the disappearing sea ice, that water will flow into the oceans and raise sea levels. The Paris climate agreement is set to go into effect Friday with the aim of meeting an ambitious goal: preventing global temperatures from rising 2 degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial levels. But, by Notz's calculations, Arctic summer sea ice will already be gone if temperatures reach that threshold. That sea ice could survive, however, if the more aggressive target of 1.5 degrees Celsius warming is attained. Further complicating things, the Arctic is heating up faster than the rest of the world, perhaps two or three times faster, Notz says. Trenberth points out that greenhouse gas emissions can also have a delayed effect. So even if humans suddenly stopped emitting carbon altogether, temperatures likely still would rise. And, he says, although scientists have been discussing ways to extract CO2 from the atmosphere, "this is an extremely difficult thing to really achieve." Looking at the sea ice loss in the Arctic is "a really stark indicator of climate change," Meier says. "We think of the Arctic as a cold place, but in a lot of ways it's relatively warm," he says. During the summer, many sections sit on the cusp of the freezing point. So, while the difference between 80 and 82 degrees Fahrenheit might not make a huge difference in Washington D.C., Meier explains, if you go from 31 to 33 degrees in the Arctic, it's the difference between ice skating and swimming. While this study doesn't really add new information for scientists, Meier says, with Arctic sea ice far from most people's everyday lives and carbon emissions, "it really helps people understand and visualize the impact."


News Article | November 3, 2016
Site: www.csmonitor.com

Climate scientists have calculated just how fast humans' carbon emissions are melting Arctic sea ice in a new study. Just 75 miles in a fossil-fuel powered car equals one square foot of ice melted Arctic ice. No more watching videos at work: Facebook will now default to audio Sorry polar bears, the Arctic Ocean might be free of sea ice before 2050. According to new calculations, for every metric ton of carbon dioxide emitted, about three square meters (approximately 32.3 square feet) of Arctic summer sea ice disappears. And, with humans currently emitting about 35 to 40 million tons of CO2 each year, the future doesn't look very frozen. It's not hard to rack up those emissions. About 2,433 miles of driving – roughly the distance from Washington, DC to Las Vegas – or just one seat on a return flight from New York to London – on average produces a metric ton of CO2 emissions. Or, for those who aren't long-distance travelers, just over 75 miles of driving in a typical fossil-fuel powered car produces enough emissions to melt one square foot of ice. That's according to Dirk Notz, head of a research group at the Max Planck Institute for Meteorology in Germany that studies sea ice. Dr. Notz calculated the relationship between CO2 emissions and the loss of Arctic summer sea ice as lead author of a paper published Thursday in the journal Science. "Our study now provides individuals with the sense that their own individual actions make a difference," Notz tells The Christian Science Monitor in a phone interview. "If I decide to drive my car a little less or to buy a car that uses less fuel, for example, all these little actions will make a difference for sea ice." Technically, Notz has calculated when there will be less than 1 million square kilometers (386,000 square miles) of Arctic sea ice left in September, after summer melting, a measurement commonly used to define sea ice free conditions. Winter temperatures will continue to freeze parts of the Arctic Ocean. That 1 million square kilometers "seems like quite a lot of ice," says Walter Meier, a sea ice researcher at the NASA Goddard Space Flight Center who was not part of the study. "But in reality it's not that much." "The Arctic Ocean will be for all intents and purposes a blue Arctic Ocean" when that happens, he says. Dr. Meier says Notz's calculations oversimplify the relationship between carbon emissions and Arctic sea ice loss. "The climate system is, in reality, a lot more complex than that," he says in a phone interview with the Monitor. Kevin Trenberth of the the Climate Analysis Section at the National Center for Atmospheric Research, who also was not part of the research, agrees. "I think it's too simple because it doesn't deal with ocean transports and it doesn't deal with atmospheric transports," he says in a phone interview with the Monitor. Furthermore, Dr. Trenberth says, seasonal variations complicate trends so the calculated relationship between CO2 and sea ice loss could be off. Although he questions their methods, Trenberth agrees with the researchers that the Arctic will see an ice-free September. And, he says, it could be as soon as in the 2030s. What would a world with a blue Arctic look like? "We're changing ice that has been around for many years to, mostly, ice that forms every year," James Overland, an oceanographer at the NOAA Pacific Marine Environmental Laboratory who was not part of the study, tells the Monitor in a phone interview. In decades past, ice would build up and become thicker through the winter. While some of that ice would melt during the summer, most would remain to accumulate more ice year after year. Animals like polar bears and walruses use those thicker sheets of ice as a sort of home base when hunting. Thinner and more fragmented ice could destroy their lifestyles. And that's not just true for animals; a disrupted icy ecosystem could make it more difficult for native human populations to hunt and forage too. But loss of Arctic sea ice probably won't just have a local impact. "Arctic sea ice regulates the temperature of our planet by cooling the Atlantic and Pacific waters," David Barber, a sea ice and climate scientist at the University of Manitoba, who was not involved in the research, writes in an email to the Monitor. Some research has suggested that less Arctic ice could lead to a weakening of the jet stream, an atmospheric system that affects the global climate. This shift could be leading to more extreme weather events, like flooding, freezing, and even droughts, already. And on top of that, Arctic sea ice serves as a sort of refrigerator for the planet, Notz explains. When the summer sun rays hit the vast, bright ice, much of that energy is reflected back. But the dark waters of a blue ocean will absorb that heat, leading to even more warming and melting. Then, warmer, more wave-filled waters can eat away at other geological features, including glaciers, coastlines, and permafrost, in a spiral of changes. It is important to note, however, that melting Arctic sea ice will not directly raise sea levels. Like melting ice in a soda glass, the oceans won't spill over from ice that is already floating in water. But as ice on land, such as the Greenland ice sheet, melts as an indirect effect of the disappearing sea ice, that water will flow into the oceans and raise sea levels. The Paris climate agreement is set to go into effect Friday with the aim of meeting an ambitious goal: preventing global temperatures from rising 2 degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial levels. But, by Notz's calculations, Arctic summer sea ice will already be gone if temperatures reach that threshold. That sea ice could survive, however, if the more aggressive target of 1.5 degrees Celsius warming is attained. Further complicating things, the Arctic is heating up faster than the rest of the world, perhaps two or three times faster, Notz says. Trenberth points out that greenhouse gas emissions can also have a delayed effect. So even if humans suddenly stopped emitting carbon altogether, temperatures likely still would rise. And, he says, although scientists have been discussing ways to extract CO2 from the atmosphere, "this is an extremely difficult thing to really achieve." Looking at the sea ice loss in the Arctic is "a really stark indicator of climate change," Meier says. "We think of the Arctic as a cold place, but in a lot of ways it's relatively warm," he says. During the summer, many sections sit on the cusp of the freezing point. So, while the difference between 80 and 82 degrees Fahrenheit might not make a huge difference in Washington D.C., Meier explains, if you go from 31 to 33 degrees in the Arctic, it's the difference between ice skating and swimming. While this study doesn't really add new information for scientists, Meier says, with Arctic sea ice far from most people's everyday lives and carbon emissions, "it really helps people understand and visualize the impact."


News Article | November 3, 2016
Site: www.csmonitor.com

Climate scientists have calculated just how fast humans' carbon emissions are melting Arctic sea ice in a new study. Just 75 miles in a fossil-fuel powered car equals one square foot of ice melted Arctic ice. No more watching videos at work: Facebook will now default to audio Sorry polar bears, the Arctic Ocean might be free of sea ice before 2050. According to new calculations, for every metric ton of carbon dioxide emitted, about three square meters (approximately 32.3 square feet) of Arctic summer sea ice disappears. And, with humans currently emitting about 35 to 40 million tons of CO2 each year, the future doesn't look very frozen. It's not hard to rack up those emissions. About 2,433 miles of driving – roughly the distance from Washington, DC to Las Vegas – or just one seat on a return flight from New York to London – on average produces a metric ton of CO2 emissions. Or, for those who aren't long-distance travelers, just over 75 miles of driving in a typical fossil-fuel powered car produces enough emissions to melt one square foot of ice. That's according to Dirk Notz, head of a research group at the Max Planck Institute for Meteorology in Germany that studies sea ice. Dr. Notz calculated the relationship between CO2 emissions and the loss of Arctic summer sea ice as lead author of a paper published Thursday in the journal Science. "Our study now provides individuals with the sense that their own individual actions make a difference," Notz tells The Christian Science Monitor in a phone interview. "If I decide to drive my car a little less or to buy a car that uses less fuel, for example, all these little actions will make a difference for sea ice." Technically, Notz has calculated when there will be less than 1 million square kilometers (386,000 square miles) of Arctic sea ice left in September, after summer melting, a measurement commonly used to define sea ice free conditions. Winter temperatures will continue to freeze parts of the Arctic Ocean. That 1 million square kilometers "seems like quite a lot of ice," says Walter Meier, a sea ice researcher at the NASA Goddard Space Flight Center who was not part of the study. "But in reality it's not that much." "The Arctic Ocean will be for all intents and purposes a blue Arctic Ocean" when that happens, he says. Dr. Meier says Notz's calculations oversimplify the relationship between carbon emissions and Arctic sea ice loss. "The climate system is, in reality, a lot more complex than that," he says in a phone interview with the Monitor. Kevin Trenberth of the the Climate Analysis Section at the National Center for Atmospheric Research, who also was not part of the research, agrees. "I think it's too simple because it doesn't deal with ocean transports and it doesn't deal with atmospheric transports," he says in a phone interview with the Monitor. Furthermore, Dr. Trenberth says, seasonal variations complicate trends so the calculated relationship between CO2 and sea ice loss could be off. Although he questions their methods, Trenberth agrees with the researchers that the Arctic will see an ice-free September. And, he says, it could be as soon as in the 2030s. What would a world with a blue Arctic look like? "We're changing ice that has been around for many years to, mostly, ice that forms every year," James Overland, an oceanographer at the NOAA Pacific Marine Environmental Laboratory who was not part of the study, tells the Monitor in a phone interview. In decades past, ice would build up and become thicker through the winter. While some of that ice would melt during the summer, most would remain to accumulate more ice year after year. Animals like polar bears and walruses use those thicker sheets of ice as a sort of home base when hunting. Thinner and more fragmented ice could destroy their lifestyles. And that's not just true for animals; a disrupted icy ecosystem could make it more difficult for native human populations to hunt and forage too. But loss of Arctic sea ice probably won't just have a local impact. "Arctic sea ice regulates the temperature of our planet by cooling the Atlantic and Pacific waters," David Barber, a sea ice and climate scientist at the University of Manitoba, who was not involved in the research, writes in an email to the Monitor. Some research has suggested that less Arctic ice could lead to a weakening of the jet stream, an atmospheric system that affects the global climate. This shift could be leading to more extreme weather events, like flooding, freezing, and even droughts, already. And on top of that, Arctic sea ice serves as a sort of refrigerator for the planet, Notz explains. When the summer sun rays hit the vast, bright ice, much of that energy is reflected back. But the dark waters of a blue ocean will absorb that heat, leading to even more warming and melting. Then, warmer, more wave-filled waters can eat away at other geological features, including glaciers, coastlines, and permafrost, in a spiral of changes. It is important to note, however, that melting Arctic sea ice will not directly raise sea levels. Like melting ice in a soda glass, the oceans won't spill over from ice that is already floating in water. But as ice on land, such as the Greenland ice sheet, melts as an indirect effect of the disappearing sea ice, that water will flow into the oceans and raise sea levels. The Paris climate agreement is set to go into effect Friday with the aim of meeting an ambitious goal: preventing global temperatures from rising 2 degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial levels. But, by Notz's calculations, Arctic summer sea ice will already be gone if temperatures reach that threshold. That sea ice could survive, however, if the more aggressive target of 1.5 degrees Celsius warming is attained. Further complicating things, the Arctic is heating up faster than the rest of the world, perhaps two or three times faster, Notz says. Trenberth points out that greenhouse gas emissions can also have a delayed effect. So even if humans suddenly stopped emitting carbon altogether, temperatures likely still would rise. And, he says, although scientists have been discussing ways to extract CO2 from the atmosphere, "this is an extremely difficult thing to really achieve." Looking at the sea ice loss in the Arctic is "a really stark indicator of climate change," Meier says. "We think of the Arctic as a cold place, but in a lot of ways it's relatively warm," he says. During the summer, many sections sit on the cusp of the freezing point. So, while the difference between 80 and 82 degrees Fahrenheit might not make a huge difference in Washington D.C., Meier explains, if you go from 31 to 33 degrees in the Arctic, it's the difference between ice skating and swimming. While this study doesn't really add new information for scientists, Meier says, with Arctic sea ice far from most people's everyday lives and carbon emissions, "it really helps people understand and visualize the impact."


News Article | November 3, 2016
Site: www.csmonitor.com

Climate scientists have calculated just how fast humans' carbon emissions are melting Arctic sea ice in a new study. Just 75 miles in a fossil-fuel powered car equals one square foot of ice melted Arctic ice. No more watching videos at work: Facebook will now default to audio Sorry polar bears, the Arctic Ocean might be free of sea ice before 2050. According to new calculations, for every metric ton of carbon dioxide emitted, about three square meters (approximately 32.3 square feet) of Arctic summer sea ice disappears. And, with humans currently emitting about 35 to 40 million tons of CO2 each year, the future doesn't look very frozen. It's not hard to rack up those emissions. About 2,433 miles of driving – roughly the distance from Washington, DC to Las Vegas – or just one seat on a return flight from New York to London – on average produces a metric ton of CO2 emissions. Or, for those who aren't long-distance travelers, just over 75 miles of driving in a typical fossil-fuel powered car produces enough emissions to melt one square foot of ice. That's according to Dirk Notz, head of a research group at the Max Planck Institute for Meteorology in Germany that studies sea ice. Dr. Notz calculated the relationship between CO2 emissions and the loss of Arctic summer sea ice as lead author of a paper published Thursday in the journal Science. "Our study now provides individuals with the sense that their own individual actions make a difference," Notz tells The Christian Science Monitor in a phone interview. "If I decide to drive my car a little less or to buy a car that uses less fuel, for example, all these little actions will make a difference for sea ice." Technically, Notz has calculated when there will be less than 1 million square kilometers (386,000 square miles) of Arctic sea ice left in September, after summer melting, a measurement commonly used to define sea ice free conditions. Winter temperatures will continue to freeze parts of the Arctic Ocean. That 1 million square kilometers "seems like quite a lot of ice," says Walter Meier, a sea ice researcher at the NASA Goddard Space Flight Center who was not part of the study. "But in reality it's not that much." "The Arctic Ocean will be for all intents and purposes a blue Arctic Ocean" when that happens, he says. Dr. Meier says Notz's calculations oversimplify the relationship between carbon emissions and Arctic sea ice loss. "The climate system is, in reality, a lot more complex than that," he says in a phone interview with the Monitor. Kevin Trenberth of the the Climate Analysis Section at the National Center for Atmospheric Research, who also was not part of the research, agrees. "I think it's too simple because it doesn't deal with ocean transports and it doesn't deal with atmospheric transports," he says in a phone interview with the Monitor. Furthermore, Dr. Trenberth says, seasonal variations complicate trends so the calculated relationship between CO2 and sea ice loss could be off. Although he questions their methods, Trenberth agrees with the researchers that the Arctic will see an ice-free September. And, he says, it could be as soon as in the 2030s. What would a world with a blue Arctic look like? "We're changing ice that has been around for many years to, mostly, ice that forms every year," James Overland, an oceanographer at the NOAA Pacific Marine Environmental Laboratory who was not part of the study, tells the Monitor in a phone interview. In decades past, ice would build up and become thicker through the winter. While some of that ice would melt during the summer, most would remain to accumulate more ice year after year. Animals like polar bears and walruses use those thicker sheets of ice as a sort of home base when hunting. Thinner and more fragmented ice could destroy their lifestyles. And that's not just true for animals; a disrupted icy ecosystem could make it more difficult for native human populations to hunt and forage too. But loss of Arctic sea ice probably won't just have a local impact. "Arctic sea ice regulates the temperature of our planet by cooling the Atlantic and Pacific waters," David Barber, a sea ice and climate scientist at the University of Manitoba, who was not involved in the research, writes in an email to the Monitor. Some research has suggested that less Arctic ice could lead to a weakening of the jet stream, an atmospheric system that affects the global climate. This shift could be leading to more extreme weather events, like flooding, freezing, and even droughts, already. And on top of that, Arctic sea ice serves as a sort of refrigerator for the planet, Notz explains. When the summer sun rays hit the vast, bright ice, much of that energy is reflected back. But the dark waters of a blue ocean will absorb that heat, leading to even more warming and melting. Then, warmer, more wave-filled waters can eat away at other geological features, including glaciers, coastlines, and permafrost, in a spiral of changes. It is important to note, however, that melting Arctic sea ice will not directly raise sea levels. Like melting ice in a soda glass, the oceans won't spill over from ice that is already floating in water. But as ice on land, such as the Greenland ice sheet, melts as an indirect effect of the disappearing sea ice, that water will flow into the oceans and raise sea levels. The Paris climate agreement is set to go into effect Friday with the aim of meeting an ambitious goal: preventing global temperatures from rising 2 degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial levels. But, by Notz's calculations, Arctic summer sea ice will already be gone if temperatures reach that threshold. That sea ice could survive, however, if the more aggressive target of 1.5 degrees Celsius warming is attained. Further complicating things, the Arctic is heating up faster than the rest of the world, perhaps two or three times faster, Notz says. Trenberth points out that greenhouse gas emissions can also have a delayed effect. So even if humans suddenly stopped emitting carbon altogether, temperatures likely still would rise. And, he says, although scientists have been discussing ways to extract CO2 from the atmosphere, "this is an extremely difficult thing to really achieve." Looking at the sea ice loss in the Arctic is "a really stark indicator of climate change," Meier says. "We think of the Arctic as a cold place, but in a lot of ways it's relatively warm," he says. During the summer, many sections sit on the cusp of the freezing point. So, while the difference between 80 and 82 degrees Fahrenheit might not make a huge difference in Washington D.C., Meier explains, if you go from 31 to 33 degrees in the Arctic, it's the difference between ice skating and swimming. While this study doesn't really add new information for scientists, Meier says, with Arctic sea ice far from most people's everyday lives and carbon emissions, "it really helps people understand and visualize the impact."


News Article | November 3, 2016
Site: www.csmonitor.com

Climate scientists have calculated just how fast humans' carbon emissions are melting Arctic sea ice in a new study. Just 75 miles in a fossil-fuel powered car equals one square foot of ice melted Arctic ice. No more watching videos at work: Facebook will now default to audio Sorry polar bears, the Arctic Ocean might be free of sea ice before 2050. According to new calculations, for every metric ton of carbon dioxide emitted, about three square meters (approximately 32.3 square feet) of Arctic summer sea ice disappears. And, with humans currently emitting about 35 to 40 million tons of CO2 each year, the future doesn't look very frozen. It's not hard to rack up those emissions. About 2,433 miles of driving – roughly the distance from Washington, DC to Las Vegas – or just one seat on a return flight from New York to London – on average produces a metric ton of CO2 emissions. Or, for those who aren't long-distance travelers, just over 75 miles of driving in a typical fossil-fuel powered car produces enough emissions to melt one square foot of ice. That's according to Dirk Notz, head of a research group at the Max Planck Institute for Meteorology in Germany that studies sea ice. Dr. Notz calculated the relationship between CO2 emissions and the loss of Arctic summer sea ice as lead author of a paper published Thursday in the journal Science. "Our study now provides individuals with the sense that their own individual actions make a difference," Notz tells The Christian Science Monitor in a phone interview. "If I decide to drive my car a little less or to buy a car that uses less fuel, for example, all these little actions will make a difference for sea ice." Technically, Notz has calculated when there will be less than 1 million square kilometers (386,000 square miles) of Arctic sea ice left in September, after summer melting, a measurement commonly used to define sea ice free conditions. Winter temperatures will continue to freeze parts of the Arctic Ocean. That 1 million square kilometers "seems like quite a lot of ice," says Walter Meier, a sea ice researcher at the NASA Goddard Space Flight Center who was not part of the study. "But in reality it's not that much." "The Arctic Ocean will be for all intents and purposes a blue Arctic Ocean" when that happens, he says. Dr. Meier says Notz's calculations oversimplify the relationship between carbon emissions and Arctic sea ice loss. "The climate system is, in reality, a lot more complex than that," he says in a phone interview with the Monitor. Kevin Trenberth of the the Climate Analysis Section at the National Center for Atmospheric Research, who also was not part of the research, agrees. "I think it's too simple because it doesn't deal with ocean transports and it doesn't deal with atmospheric transports," he says in a phone interview with the Monitor. Furthermore, Dr. Trenberth says, seasonal variations complicate trends so the calculated relationship between CO2 and sea ice loss could be off. Although he questions their methods, Trenberth agrees with the researchers that the Arctic will see an ice-free September. And, he says, it could be as soon as in the 2030s. What would a world with a blue Arctic look like? "We're changing ice that has been around for many years to, mostly, ice that forms every year," James Overland, an oceanographer at the NOAA Pacific Marine Environmental Laboratory who was not part of the study, tells the Monitor in a phone interview. In decades past, ice would build up and become thicker through the winter. While some of that ice would melt during the summer, most would remain to accumulate more ice year after year. Animals like polar bears and walruses use those thicker sheets of ice as a sort of home base when hunting. Thinner and more fragmented ice could destroy their lifestyles. And that's not just true for animals; a disrupted icy ecosystem could make it more difficult for native human populations to hunt and forage too. But loss of Arctic sea ice probably won't just have a local impact. "Arctic sea ice regulates the temperature of our planet by cooling the Atlantic and Pacific waters," David Barber, a sea ice and climate scientist at the University of Manitoba, who was not involved in the research, writes in an email to the Monitor. Some research has suggested that less Arctic ice could lead to a weakening of the jet stream, an atmospheric system that affects the global climate. This shift could be leading to more extreme weather events, like flooding, freezing, and even droughts, already. And on top of that, Arctic sea ice serves as a sort of refrigerator for the planet, Notz explains. When the summer sun rays hit the vast, bright ice, much of that energy is reflected back. But the dark waters of a blue ocean will absorb that heat, leading to even more warming and melting. Then, warmer, more wave-filled waters can eat away at other geological features, including glaciers, coastlines, and permafrost, in a spiral of changes. It is important to note, however, that melting Arctic sea ice will not directly raise sea levels. Like melting ice in a soda glass, the oceans won't spill over from ice that is already floating in water. But as ice on land, such as the Greenland ice sheet, melts as an indirect effect of the disappearing sea ice, that water will flow into the oceans and raise sea levels. The Paris climate agreement is set to go into effect Friday with the aim of meeting an ambitious goal: preventing global temperatures from rising 2 degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial levels. But, by Notz's calculations, Arctic summer sea ice will already be gone if temperatures reach that threshold. That sea ice could survive, however, if the more aggressive target of 1.5 degrees Celsius warming is attained. Further complicating things, the Arctic is heating up faster than the rest of the world, perhaps two or three times faster, Notz says. Trenberth points out that greenhouse gas emissions can also have a delayed effect. So even if humans suddenly stopped emitting carbon altogether, temperatures likely still would rise. And, he says, although scientists have been discussing ways to extract CO2 from the atmosphere, "this is an extremely difficult thing to really achieve." Looking at the sea ice loss in the Arctic is "a really stark indicator of climate change," Meier says. "We think of the Arctic as a cold place, but in a lot of ways it's relatively warm," he says. During the summer, many sections sit on the cusp of the freezing point. So, while the difference between 80 and 82 degrees Fahrenheit might not make a huge difference in Washington D.C., Meier explains, if you go from 31 to 33 degrees in the Arctic, it's the difference between ice skating and swimming. While this study doesn't really add new information for scientists, Meier says, with Arctic sea ice far from most people's everyday lives and carbon emissions, "it really helps people understand and visualize the impact."


News Article | December 23, 2016
Site: www.washingtonpost.com

Last month, temperatures in the high Arctic spiked dramatically, some 36 degrees Fahrenheit above normal — a move that corresponded with record low levels of Arctic sea ice during a time of year when this ice is supposed to be expanding during the freezing polar night. And now this week, as you can see above, we’re seeing another huge burst of Arctic warmth. A buoy close to the North Pole just reported temperatures close to the freezing point of 32 degrees Fahrenheit (0 Celsius), which is 10s of degrees warmer than normal for this time of year. Although it isn’t clear yet, we could now be in for another period when sea ice either pauses its spread across the Arctic ocean, or reverses course entirely. But these bursts of Arctic warmth don’t stand alone — last month, extremely warm North Pole temperatures corresponded with extremely cold temperatures over Siberia. This week, meanwhile, there are large bursts of un-seasonally cold air over Alaska and Siberia once again. It is all looking rather consistent with an outlook that has been dubbed “Warm Arctic, Cold Continents” — a notion that remains scientifically contentious but, if accurate, is deeply consequential for how climate change could unfold in the Northern Hemisphere winter. The core idea here begins with the fact that the Arctic is warming up faster than the mid-latitudes and the equator, and losing its characteristic floating sea ice cover in the process. This also changes the Arctic atmosphere, the theory goes, and these changes interact with large scale atmospheric patterns that affect our weather (phenomena like the jet stream and the polar vortex). We won’t get into the details yet, but in essence, the result can be a kind of swapping of the cold air masses of the Arctic with the warm air masses to the south of them. The Arctic then gets hot (relatively), and the mid-latitudes — including sometimes, as during the infamous “polar vortex” event of 2013-2014, the United States — get cold. Here’s an animation, provided by Jason Box of the Geological Survey of Denmark and Greenland, of what this might look like. It shows that both during the November major Arctic warming event, and again this week, temperatures over the Arctic ocean spiked far above their average, while temperatures over some high or mid-latitude land surfaces in the Northern Hemisphere fell well below average (the Arctic is at the far right): The image, Box explained by email, “underscores the distinction between ocean and land and thus points to there being something to the pattern” of “Warm Arctic, Cold Continents.” He continued: In recent years, several scientists have come up with different versions or incarnations of the “Warm Arctic, Cold Continents” idea. One of the best known is Rutgers University climate scientist and Arctic specialist Jennifer Francis, who published a 2012 paper with Stephen Vavrus of the University of Wisconsin-Madison arguing that the “Arctic amplification” of global warming was leading to a more wavy and slower-moving jet stream, and this in turn was leading to extreme weather as different atmospheric patterns became stuck in place. Their paper highlighted not only changes in winter, but also throughout the year. “What I think we’ve been seeing this year has been totally consistent with the hypothesis that we’ve been working on,” Francis said in an interview of the recent Arctic drama. The jet stream is a global west-to-east flow (Francis often calls it a “river”) of air above our heads that carries with it weather we experience. But sometimes, the flow becomes quite elongated, looking much less like a tight loop around the planet and more like a series of slowly undulating waves. “What I think is happening is that it’s been very warm in the Arctic all year long and this has helped favor a very wavy jet stream, which is what we’ve been seeing,” she continued, “and that has helped to pump a lot of extra heat and moisture up into the Arctic.” But then what about the cold continents? Judah Cohen, the head of seasonal forecasting at Atmospheric and Environmental Research, said that this year in particular, low sea ice in the Arctic has led to a situation in which more snow falls over Siberia in the late fall, as Arctic moisture unlocked from the uncovered ocean gets pulled south over land and falls as snow. This doesn’t just make Siberia cold. Cohen believes it creates atmospheric reverberating effects that upset the polar vortex (the cold lower pressure region that normally hovers over the Arctic in winter), causing it to become elongated, migrate southward, and allowing for the swapping of Arctic cold and mid-latitude warmth. “This year, we had this unprecedented early polar votex weakening, polar vortex split, and that really kicked off this continental cooling we’ve seen this winter,” said Cohen. “It started across Eurasia but obviously in December it’s come over North America as well, and so far there’s no signs of that going away.” But as Cohen acknowledges, “the community is definitely polarized” over the validity of these ideas. “People are saying that [they] feel very strongly that any kind of cold that we’re seeing in the winter is just a product of natural variability, and there’s no forcing of it from the Arctic, let’s say. But I mean, I think every time you get a cold winter, that argument gets harder and harder to make.” Another early theorist of the “Warm Arctic, Cold Continents” concept is James Overland, a researcher with the Pacific Marine Environmental Laboratory of the National Oceanic and Atmospheric Administration, who co-authored a paper on the topic in 2011, just after a record-breaking snowy Washington, D.C. winter in 2010. It concluded: “There are a lot of people in both camps,” Overland now says of the debate over these ideas. “It’s fairly evenly matched.” But as he continues, referring to the present moment, “I think there’s a strong case to be made that we’re seeing the first real strong example of the loss of sea ice north of Alaska helping to lock in the longwave pattern and the cold temperatures on the East Coast.” (Francis, Cohen, and Overland were all co-authors of a 2014 review paper that looked at the evidence for whether the warming Arctic was indeed causing extreme weather effects in the mid-latitudes.) If these ideas are correct, they’re hugely important — and not only because of the consequences for the weather we all experience in the mid-latitudes of the Northern Hemisphere. It’s also important because paradoxically, it could give momentum to climate change doubters, who will constantly be pointing to major snowstorms and cold temperatures where they live in order to cast doubt on the overall climate trend, even though it would be precisely that trend that is driving those select bouts of cold (even as the globe overall still shows a warming trend). Recently I checked in with one of the major skeptics of all of this — National Center for Atmospheric Research climate scientist Kevin Trenberth, who has debated Francis in the past, arguing that much of what she’s citing could be chalked up to natural climate variability and noting that climate change models don’t produce these effects. Trenberth didn’t deny that the fast-warming Arctic could have some ramifications outside of the Arctic. But he pointed out that the tropics of the Earth have a greater pull on weather overall and argued that processes happening in the Arctic winter aren’t that powerful, in the perspective of the globe as a whole. As he put it: In fact, in a sign of possible moderating of the debate, Francis said she agrees that “the tropics rule the world,” and the Arctic is acting as more of a modulator. “We’re saying that they do rule the world in a way but the Arctic can really change how their natural influence would typically happen. We’re seeing them intensify a pattern or maybe even reduce it.” For instance, if tropical weather causes a major excursion of the jet stream northward, Arctic warming can then exacerbate that, she said. So for now, these ideas aren’t accepted by all of the relevant scientists – but they definitely have a core group of supporters who are publishing, arguing, and citing recent events to advance their case. Scientists are gathering in Washington, D.C. in February to hash them out further – by which time, we’ll know more about just how much winter weather itself has given momentum to the conversation. “We continue to see this Arctic behaving so bizarrely, I think we’re in for a very interesting winter,” said Francis. President Obama bans oil drilling in large parts of the Arctic and Atlantic oceans The Energy Dept. helped start a revolution — and it doesn’t know who to hand it off to In the age of Trump, a climate change libel suit heads to trial The coming battle between economists and the Trump team over the true cost of climate change For more, you can sign up for our weekly newsletter here and follow us on Twitter here.

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