NOAA Ship Fairweather Maps Aid Shipping Through Bering Straits

As Arctic ice recedes, countries are looking forward to faster, safer and more efficient sea routes across the top of the world. Responding to a request from the U.S. Navy, U.S. Coast Guard, Alaska Maritime Pilots and the commercial shipping industry, NOAA sent one of its premier surveying vessels, NOAA Ship Fairweather, to detect navigational dangers in critical Arctic waters that have not been charted for more than 50 years.

Fairweather, whose homeport is Ketchikan, Alaska, will spend July and August examining seafloor features, measuring ocean depths and supplying data for updating NOAA's nautical charts spanning 350 square nautical miles in the Bering Straits around Cape Prince of Wales. The data will also support scientific research on essential fish habitat and will establish new tidal datums in the region.
Just as the growing numbers of cars on the road cause traffic "chokepoints," more ships traversing northern passageways can choke maritime traffic. These maritime traffic snarls occur when nautical charts are outdated, ships do not have sufficient information for navigation or changing maritime conditions -- like sea level rise or movements of the seafloor -- are not tracked.
"We have seen a substantial increase in activity in the region and ships are operating with woefully outdated charts," said Sen. Lisa Murkowski of Alaska. "I have introduced legislation that authorizes a significant increase in funding for mapping the Arctic, and I am pleased to see NOAA beginning the process. While this is a good start, we still need more resources to adequately map this region."
"Commercial shippers aren't the only ones needing assurances of safety in new trade routes," notes Captain John Lowell, director of NOAA's Office of Coast Survey. "The additional potential for passenger cruises, commercial fishing and other economic activities add to pressures for adequate response to navigational risks."
The U.S. Exclusive Economic Zone includes 568,000 square nautical miles of U.S. Arctic waters. The majority of charted Arctic waters were surveyed with obsolete technology dating back to the 1800s. Most of the shoreline along Alaska's northern and western coasts has not been mapped since 1960, if ever, and confidence in the region's nautical charts is extremely low.
"In Alaska we are seeing the effects of climate change more rapidly than anywhere else in the U.S.," said Sen. Mark Begich of Alaska. "As Arctic sea ice recedes, economic activity in the region is going to expand dramatically. Alaskans rely on NOAA to help us make sure that things like oil and gas development and marine transportation are done safely and responsibly. The 21st century mapping technology the Ketchikan-based Fairweather brings to this important charting mission is a great example of what the federal government needs to do as activity in the Arctic grows."
About a third of U.S. Arctic waters are considered navigationally significant. Of that area, NOAA's Office of Coast Survey has identified 38,000 square nautical miles as survey priorities. NOAA estimates that it will take well more than 25 years to map the prioritized areas of the Arctic seafloor.
"President Thomas Jefferson ordered a survey of the East Coast in 1807, when our country was losing more ships to unsafe navigation than to war," explains Capt. David Neander, commanding officer of the Fairweather. "Today, we have better maps of the moon than of our own oceans. Our46-person crew is amassing ocean data that directly affects our economy and our ecosystems."
The vessel is equipped with the latest in hydrographic survey technology -- multi-beam survey systems; high-speed, high-resolution side-scan sonar; position and orientation systems; hydrographic survey launches; and an on-board data-processing server.
Fairweather is part of the NOAA fleet of ships and aircraft operated, managed and maintained by NOAA's Office of Marine and Aviation Operations, which includes commissioned officers of the NOAA Corps and civilian wage mariners.
Updated charts for commercial and recreational navigation are available on Coast Survey's Web site, http://www.nauticalcharts.noaa.gov/.

Sea Ice in the Arctic Not Recovering: Another Critical Minimum Forecast

A critical minimum for Arctic sea ice can again be expected for late summer 2010, according to researchers.

Scientists from the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association (AWI) in Bremerhaven and from KlimaCampus of the University of Hamburg have now published data in this context in the annual issue of Sea Ice Outlook. The online publication compares the forecasts on ice cover for September 2010 prepared by around a dozen international research institutes in a scientific "competition." The ice reaches its minimum area at this time every year.

The forecast developed by the team from KlimaCampus of the University of Hamburg, i.e. 4.7 million square kilometres (km²), is more negative than that submitted by the AWI researchers, who arrived at a figure of 5.2 million km². Nevertheless, neither of the two research groups anticipates that the record minimum of 4.3 million km² in 2007 will be reached.

Although Arctic ice currently has an area of ten million km², which is half a million km² smaller than in 2007, one cannot directly conclude a new record minimum in late summer. The present ice cover is comparable to that in June 2006, a year when more ice area remained in September than in 2007. The decisive factors for the situation in late summer, such as the ice thickness in the central Arctic and further development of the weather in summer, are not yet known, however.

There is no reason for an all-clear: scientists basically assume a long-term decrease in sea ice cover for the northern polar region in the summers of the coming decades. Even though the trend in terms of area points slightly upward (2007: 4.3 million km², 2008: 4.68 million km², 2009: 5.36 million km²), the Arctic ice area from 1980 to 1990 was constantly greater than seven million km².

The two teams of scientists prepared their forecasts using different methods. Prof. Rüdiger Gerdes and his team from the Alfred Wegener Institute in conjunction with the scientific companies OASys and FastOpt jointly developed a model based on observation data from oceanic drift buoys and satellite data on ice measurement and ice movement. In the course of the summer the submitted forecast will be repeated on a monthly basis taking into account up-to-date weather data. "Currently we calculate that with 80% probability the ice cover in September will be between 4.7 and 5.7 million km2. However, the forecast will be more and more precise," says Prof. Rüdiger Gerdes.

The forecast developed by the KlimaCampus team headed by Prof. Lars Kaleschke, on the other hand, compares the ice area on every day of the year 2010 to that on the respective day from 2009 to 2003 on the basis of satellite pictures. The number and size of the ice-free areas, so-called polynyas, are indicators for later ice development. These dark ocean areas store solar energy already in early summer and thus additionally reinforce further melting during the polar summer, in which the sun no longer disappears, up to September. Alfred Wegener Institute (2010, June 24). Sea ice in the Arctic not recovering: Another critical minimum forecast. ScienceDaily. Retrieved June 28, 2010, from http://www.sciencedaily.com/releases/2010/06/100624112306.htm

Scientists Call for a New Strategy for Polar Ocean Observation

In a report published in Science, a team of oceanographers, including MBL (Marine Biological Laboratory) Ecosystems Center director Hugh Ducklow, outline a polar ocean observation strategy they say will revolutionize scientists' understanding of marine ecosystem response to climate change. The approach, which calls for the use of a suite of automated technologies that complement traditional data collection, could serve as a model for marine ecosystems worldwide and help form the foundation for a comprehensive polar ocean observation system.

The complexity of marine food webs and the "chronic under-sampling" of the world's oceans present major constraints to predicting the future of and optimally managing and protecting marine resources. "We know more about Venus than we do about the Earth's oceans," says Ducklow. "We need an ocean observation system analogous to meteorological monitoring for weather forecasting, but it's harder to do in the ocean."

In polar oceans in particular, including the Western Antarctic Peninsula (WAP) where Ducklow and his colleagues conduct research as part of the NSF's Long-Term Ecological Research project at Palmer Station, high operation costs and harsh conditions restrict the coverage provided by research ships, where much of the data on this ecosystem is collected. To overcome these hurdles, oceanographers around the world have been developing technologies to complement traditional data collection by research ships. The coordinated use of these technologies will enable sustained observations throughout the year in the polar oceans and could form the foundation for a comprehensive observation strategy the team says.

In their report the scientists, led by Oscar Schofield of Rutgers University, describe a multi-platform approach to ocean observation, where data is collected by a host of automated sources including glider robots that measure ocean characteristics continuously for weeks at a time and tourist vessels, ferries, and other "ships of opportunity" outfitted with chemical and biological sensors. The authors also encourage the deployment of oceanographic instruments on animals such as elephant seals and penguins to provide information on animal behavior and oceanographic conditions. Recent tagging of Adélie penguins nesting near Palmer Station has helped scientists understand the link between nutrient upwelling and penguin foraging.

"We're looking for ways to use our existing capabilities to obtain data," says Ducklow. "Our goal is to make things cheaper and get a lot of them out there. This will help to narrow down uncertainty about the effects of warming on the polar oceans in the coming decades to century."

The team says the WAP is an ideal location for monitoring the impacts of rapid climate change on marine ecosystems and could serve as a model observation system for marine ecosystems worldwide. The rapid climate change in this region is driving large-scale changes in the food web, impacting everything from phytoplankton -- the foundation of the food web -- to Antarctic krill, to apex predators such as penguins, whales, and seals.

"The comprehensive deployment of these observational systems will revolutionize our understanding of how marine ecosystems are responding to climate change everywhere, not just in Antarctica," says Ducklow. "With current observation methods, the data you collect, whether it's from land or from a research vessel, is limited to access by people. Where we are only getting dozens of measurements a year from data collected by people, you could get hundreds or thousands each day with the use of automated technologies."

This paper stems from work done as part of the National Science Foundation Office of Polar Program's Long-Term Ecological Research (LTER) project at Palmer Station, Antarctica. Hugh Ducklow is the principal investigator of the Palmer LTER. Besides Ducklow and Schofield, the paper's co-authors are Douglas Martinson, Columbia University's Lamont-Doherty Earth Observatory; Michael Meredith, British Antarctic Survey; Mark Moline, California Polytechnic State University; and William Fraser, Polar Oceans Research Group, Sheridan, MT.

Marine Biological Laboratory (2010, June 21). Scientists call for a new strategy for polar ocean observation. ScienceDaily. Retrieved June 22, 2010, from http://www.sciencedaily.com/releases/2010/06/100617141006.htm

Rapid Changes for Arctic Flora and Fauna

Unique Arctic habitats for flora and fauna, including sea ice, tundra, lakes, and peatlands have been disappearing over recent decades, and some characteristic Arctic species have shown a decline. The changes in Arctic Biodiversity have global repercussions and are further creating challenges for people living in the Arctic.

Arctic Biodiversity -- affected by multiple stressors

The Arctic Biodiversity Trends 2010 Report, produced by some of the world's leading experts of Arctic ecosystems and biodiversity, is the Arctic Council's contribution to the United Nations International Year of Biodiversity in 2010 and will be a preliminary product under the Arctic Council project 'Arctic Biodiversity Assessment' (ABA).

In 2008, the United Nations Environment Program passed a resolution expressing 'extreme concern' over the impacts of climate change on Arctic indigenous peoples, other communities, and biodiversity. It highlighted the potentially significant consequences of changes in the Arctic. The Arctic Biodiversity Trends -- 2010: Selected Indicators of Change report indicates that some of those anticipated impacts on Arctic biodiversity are already occurring.

The report is based on twenty-two indicators and provides a snapshot of the trends being observed in Arctic biodiversity today. The polar bear is one of the most well-known species impacted by changes in the Arctic, but it is not the only one. The indicators show that the Arctic has changed dramatically during recent decades and that unique Arctic habitats for flora and fauna are disappearing. Furthermore, some species of importance to Arctic people or species of global attention are declining.

The report presents a broad spectrum of changes in the Arctic ecosystems and biodiversity.

• Polar bears are highly specialized for and dependent on sea ice for their habitat. Therefore they are particularly sensitive and vulnerable to the documented significant reductions in sea ice cover in parts of the Arctic and to the thinning of multi-year ice in the polar basin. Status and trends for many populations are not available, but research on some populations demonstrates that they have decreased over the past several decades, and population and habitat modelling have projected substantial future declines in the distribution and abundance of polar bears.
• The vegetation comprising tundra ecosystems -- various species of grasses, sedges, mosses, and lichens -- are, in some places, being replaced by species typical of more southern locations, such as evergreen shrubs.
• Trees are beginning to encroach on the tundra at its southern margin and some models project that by 2100 the tree line will have advanced north by as much as 500 km, resulting in a loss of 51% of tundra habitat.
• In recent years, on average, the southern limit of permafrost in northern peatlands has retreated by 39 km and by as much as 200 km in some parts of Arctic. Peatlands are significant for the floristic diversity of the Arctic because their species comprise 20-30% of the Arctic and sub-Arctic flora. Moreover, many bird species with conservation priority are strongly associated with tundra and mire habitats.
• Cold water coral reefs, coral gardens, and sponge aggregations provide a habitat for a variety of fish and invertebrates and thus represent biodiversity hotspots in the Arctic seas. These habitats are vulnerable to fisheries and other human activities such as oil and gas exploration.

Depending on the magnitude of these and other changes, certain ecosystems may no longer be considered 'Arctic'. The result may be that many of the species thriving in the Arctic today are not able to survive there in the future.

A key finding in the Report is that climate change is emerging as the most far-reaching and significant stressor on Arctic biodiversity, though contaminants, habitat change, industrial development, and unsustainable harvest levels continue to have impacts.

The importance of Arctic ecosystems for biodiversity is immense and therefore a more thorough examination of the state of affairs is needed. Thus, leading Arctic scientists are currently engaged in making a full and comprehensive Arctic Biodiversity Assessment, which is expected to be completed in 2013.

International Polar Year - Oslo Science Conference (2010, June 14). Rapid changes for Arctic flora and fauna. ScienceDaily. Retrieved June 15, 2010, from http://www.sciencedaily.com/releases/2010/06/100609094134.htm

Arctic Ice at Low Point Compared to Recent Geologic History

Less ice covers the Arctic today than at any time in recent geologic history. That's the conclusion of an international group of researchers, who have compiled the first comprehensive history of Arctic ice.
For decades, scientists have strived to collect sediment cores from the difficult-to-access Arctic Ocean floor, to discover what the Arctic was like in the past. Their most recent goal: to bring a long-term perspective to the ice loss we see today.
Now, in an upcoming issue of Quarternary Science Reviews, a team led by Ohio State University has re-examined the data from past and ongoing studies -- nearly 300 in all -- and combined them to form a big-picture view of the pole's climate history stretching back millions of years.
"The ice loss that we see today -- the ice loss that started in the early 20th Century and sped up during the last 30 years -- appears to be unmatched over at least the last few thousand years," said Leonid Polyak, a research scientist at Byrd Polar Research Center at Ohio State University. Polyak is lead author of the paper and a preceding report that he and his coauthors prepared for the U.S. Climate Change Science Program.
Satellites can provide detailed measures of how much ice is covering the pole right now, but sediment cores are like fossils of the ocean's history, he explained.
"Sediment cores are essentially a record of sediments that settled at the sea floor, layer by layer, and they record the conditions of the ocean system during the time they settled. When we look carefully at various chemical and biological components of the sediment, and how the sediment is distributed -- then, with certain skills and luck, we can reconstruct the conditions at the time the sediment was deposited."
For example, scientists can search for a biochemical marker that is tied to certain species of algae that live only in ice. If that marker is present in the sediment, then that location was likely covered in ice at the time. Scientists call such markers "proxies" for the thing they actually want to measure -- in this case, the geographic extent of the ice in the past.
While knowing the loss of surface area of the ice is important, Polyak says that this work can't yet reveal an even more important fact: how the total volume of ice -- thickness as well as surface area -- has changed over time.
"Underneath the surface, the ice can be thick or thin. The newest satellite techniques and field observations allow us to see that the volume of ice is shrinking much faster than its area today. The picture is very troubling. We are losing ice very fast," he said.
"Maybe sometime down the road we'll develop proxies for the ice thickness. Right now, just looking at ice extent is very difficult."
To review and combine the data from hundreds of studies, he and his cohorts had to combine information on many different proxies as well as modern observations. They searched for patterns in the proxy data that fit together like pieces of a puzzle.
Their conclusion: the current extent of Arctic ice is at its lowest point for at least the last few thousand years.
As scientists pull more sediment cores from the Arctic, Polyak and his collaborators want to understand more details of the past ice extent and to push this knowledge further back in time.
During the summer of 2011, they hope to draw cores from beneath the Chukchi Sea, just north of the Bering Strait between Alaska and Siberia. The currents emanating from the northern Pacific Ocean bring heat that may play an important role in melting the ice across the Arctic, so Polyak expects that the history of this location will prove very important. He hopes to drill cores that date back thousands of years at the Chukchi Sea margin, providing a detailed history of interaction between oceanic currents and ice.
"Later on in this cruise, when we venture into the more central Arctic Ocean, we will aim at harvesting cores that go back even farther," he said. "If we could go as far back as a million years, that would be perfect."
Polyak's coauthors on the report hailed from Penn State University, University of Colorado, University of Massachusetts, the U.S. Geological Survey, Old Dominion University, the Geological Survey of Canada, University of Copenhagen, the Cooperative Institute for Research in Environmental Sciences, Stockholm University, McGill University, James Madison University, and the British Antarctic Survey.
This research was funded by the US Geological Survey and the National Science Foundation.

Winds from Siberia Reduce Arctic Sea Ice Cover, Norwegian Researchers Find

The ice cover in the Arctic has decreased dramatically in recent years. Norwegian researchers have discovered that changes in air circulation patterns create winds that push away the ice.

n recent years, satellite images have shown large variations in the ice cover around the North Pole. The images have also shown that the ice cover in the Arctic has diminished considerably over the past 30 years, with the most drastic reductions occurring in recent years.

Many experts believe that it is now only a matter of decades before climate change results in a totally ice-free Arctic during parts of the year. For instance, the UN Intergovernmental Panel on Climate Change (IPCC) projects that this may occur by the end of this century.

How much of the change in ice cover is caused by dramatic changes in the climate, and how much is the result of other factors? And what is causing the ice cover in the Arctic to disappear even faster than the climate models project?

The Arctic climate paradox

A few years ago, US researchers discovered what they termed the "Arctic climate paradox." Since 1980, the researchers had been observing a decrease in ice cover. They explained this through a slow process of climate change combined with fluctuations in patterns of atmospheric pressure and air currents over the Arctic. It was believed that the positive phase of the Arctic Oscillation (AO) was a major cause of the receding ice cover.

The AO is normally influenced by three pressure systems located over the Azores, Iceland and the Northern Pacific Ocean. Since 2000 the AO has been in a negative phase. As a result, researchers predicted that the pace of reduction in the ice cover would slow down.

Instead it accelerated.

Unknown factor

"The US researchers argued that the ice was responding to something else, another factor that nobody had considered," explains Asgeir Sorteberg, Associate Professor at the Geophysical Institute at the University of Bergen. He has been investigating this phenomenon along with his colleagues in the project entitled the Norwegian Component of the Ecosystem Studies of Sub-Arctic Seas (NESSAS).

When the Norwegian researchers began their work, they noticed in particular a dramatic change in the weather pattern in the Arctic beginning about the year 2000. The change corresponded to the point in time when the reduction of ice cover in the Arctic began to accelerate.

The researchers began to analyze the circulation patterns over the Arctic.

"We found that these patterns can explain in large part why the ice cover decreased so much more rapidly after 2000. Wind patterns depend on the position of major high-pressure and low-pressure systems. We discovered that months with very little ice cover and high temperatures corresponded with crucial variations in the wind patterns," explains Mr Sorteberg.

"Up until 2000, the Arctic Oscillation (AO) had the greatest impact on the winter ice cover in the Arctic. But the change around 2000 meant that more of the weather and wind over the Arctic after that year was determined by high-pressure and low-pressure systems in northern Russia. In other words, the AO, which was usually so crucial, played a much less important role."

Ice is pushed away

"We have now managed to document what has occurred in connection with this change," says Mr Sorteberg.

The changed wind direction pushes large ice masses away from the Arctic and down along the eastern coast of Greenland. At the same time, less ice forms when the winds over the Arctic are determined by the pressure systems in northern Russia rather than those over the North Atlantic and the Pacific Ocean, as is normally the case.

The conclusion from this research is that we should be cautious about using the extent of the ice cover as an indicator of the ice's climatic "state of health."

The extent of the ice cover is highly dependent on the wind direction, and short-term changes in the ice cover give very little indication of whether climate change is occurring in the Arctic.

"The dramatic changes in the extent of Arctic sea ice in recent years have mainly been caused by atmospheric circulation patterns that have tended to reduce ice cover, combined with a slow process of climate change. Variations in the circulation patterns are part of the natural fluctuations in the weather. In certain periods these fluctuations will reinforce human-made changes, while at other times they will mask them," says Mr Sorteberg.

Climate change leads to thinner ice

Mr Sorteberg believes we should be cautious about interpreting the dramatic decrease in Arctic ice cover in the past decade as an indication that the Arctic will be ice free in 10 to 20 years.

However, he emphasizes that he and his colleagues do not reject the assertion that climate change is affecting Arctic ice cover or that the IPCC is wrong when it states that the Arctic may be nearly ice free in summer towards the end of this century.

"There is no doubt that the Arctic sea ice has become thinner in recent years. The thickness of the sea ice is a much better indicator than the extent of the ice cover if we want to study how climate change may affect the ice in the Arctic," says Mr Sorteberg.

Research Council of Norway (2010, April 28). Winds from Siberia reduce Arctic sea ice cover, Norwegian researchers find. ScienceDaily. Retrieved April 29, 2010, from http://www.sciencedaily.com­ /releases/2010/04/100427111449.htm

Massive Arctic Ice Cap Is Shrinking, Study Shows; Rate Accelerating Since 1985

Close to 50 years of data show the Devon Island ice cap, one of the largest ice masses in the Canadian High Arctic, is thinning and shrinking.

A paper published in the March edition of Arctic, the journal of the University of Calgary's Arctic Institute of North America, reports that between 1961 and 1985, the ice cap grew in some years and shrank in others, resulting in an overall loss of mass. But that changed 1985 when scientists began to see a steady decline in ice volume and area each year.
"We've been seeing more mass loss since 1985," says Sarah Boon, lead author on the paper and a Geography Professor at the University of Lethbridge. The reason for the change? Warmer summers.
The High Arctic is essentially a desert with low rates of annual precipitation. There is little accumulation of snow in the winter and cool summers, with temperatures at or below freezing, serve to maintain levels. Any increase of snow and ice takes years.
This delicate equilibrium is easily upset. One warm summer can wipe out five years of growth. And though the accelerated melting trend began in 1985, the last decade has seen four years with unusually warm summers -- 2001, 2005, 2007 and 2008.
"What we see during these warm summers is the extent of the melt is greater," says Boon about the results of a five-year remote sensing study that ran between 2000 and 2004.
The white surfaces of snow and ice reflect heat -- a process known as the albedo effect. Retreating ice exposes dark soil and gravel, which absorb heat and increase the melt rate of ice along the periphery of the cap. But it's not only the edges of the cap that are losing ice. At lower altitudes the ice is thinning as well.
Changes to the Devon ice cap, which covers approximately 14,400 sq. km, could have multiple impacts on everything from ship traffic to sea level.
There has already been an increase in the number of icebergs calving off from outlet glaciers that flow into the ocean. Boon explains that melt water runs between the bottom of the glacier and the ground, creating a slippery cushion that allows the glacier to slide forward more rapidly than it would in colder conditions.
"There are a lot of things we need to consider. One is the iceberg calving and its implications for shipping. These things don't just go away, they float out into the ocean," says Boon. A second area of concern is the contribution of increased glacier melt to rising sea level.
The work of Boon and her colleagues demonstrates the importance of long-term research. Work on Devon Island began in 1961 with researchers from the Arctic Institute of North America, including long-time Arctic scientist Roy 'Fritz' Koerner, who was part of the current study until his death in 2008. This ongoing research, which is continuing thanks to federal International Polar year funding, has created a comprehensive dataset that contributes to the understanding of the complex play between the ice cap, the atmosphere and the ocean.
"We all know long-term studies are important but they are really hard to pay for."

Arctic Institute of North America (2010, April 13). Massive Arctic ice cap is shrinking, study shows; Rate accelerating since 1985.

Traditional Inuit Knowledge Combines With Science to Shape Weather Insights

Using skills passed down through generations, Inuit forecasters living in the Canadian Arctic look to the sky to tell by the way the wind scatters a cloud whether a storm is on the horizon or if it's safe to go on a hunt.

Thousands of miles away in a lab tucked in Colorado's Rocky Mountains, scientists take data measurements and use the latest computer models to predict weather. They are two practices serving the same purpose that come from disparate worlds.
But in the past 20 years, something has run amok with Inuit forecasting. Old weather signals don't seem to mean what they used to. The cloud that scatters could signal a storm that comes in an hour instead of a day.
Now researchers are combining indigenous environmental knowledge with modern science to learn new things about what's happening to the Arctic climate.
"It's interesting how the western approach is often trying to understand things without necessarily experiencing them," said Elizabeth Weatherhead, a research scientist with the University of Colorado at Boulder's Cooperative Institute for Research in Environmental Sciences. "With the Inuit, it's much more of an experiential issue, and I think that fundamental difference brings a completely different emphasis both in defining what the important scientific questions are, and discerning how to address them."
For years, researchers had heard reports of unpredictable weather coming in from Arctic communities. But the stories didn't seem to match up with the numbers. By scientific measurement, weather around the world appeared to be growing more persistent with less variation. The disparity left scientists scratching their heads, said Weatherhead.
"I had been hearing about this problem from other environmental statisticians for a number of years," said Weatherhead, who also works closely with the National Oceanic and Atmospheric Administration's Earth System Research Laboratory in Boulder, Colo., and who is chief author on a new study on the subject. "But the Inuit used a different language than what we statisticians used, and none of us could really figure out what matched up with their observations."
That's where Shari Gearheard, a scientist with CU-Boulder's National Snow and Ice Data Center, also part of CIRES, comes in. Gearheard lives in Clyde River, Nunavut, Canada, an Inuit community on eastern Baffin Island, and for the past 10 years has been working with Inuit hunters and elders to document their knowledge of the environment and environmental change.
Weather has a special importance in Arctic environments, where a reliable forecast can mean the difference between life and death. There are members of the Inuit community who possess the skills to predict the weather, but that knowledge is dying off as both the culture and climate change, according to the scientists.
"The impacts of that are a loss of confidence in those forecasters and concerns about incorrect forecasts," said Gearheard. Forecasters don't want to send somebody out to go hunting if they're going to be unsafe and be in poor weather conditions."
Gearheard meticulously collects the stories told to her by the Inuit and makes systematic records of indigenous environmental knowledge. Through this, patterns begin to emerge, she said.
Of special importance were changes experienced by the Inuit during the spring, a time of transition for many environmental processes. During spring, the Inuit would notice that the top layer of the snow melted during the day and then would refreeze at night, forming a crust.
"In fact, in a lot of places, the season is named after a particular process by the Inuit," said Gearheard. "In cases like this where the Inuit are not seeing that process anymore, it is an indicator to them that something had changed."
Gearheard's records created a resolution of detail for Arctic weather observation that, by bringing the two studies together, gave Weatherhead the information she needed to bridge indigenous knowledge with scientific knowledge. "What was incredibly helpful was Shari's detailed description of what they were experiencing on what sort of timescales," said Weatherhead. "That really allowed us to start focusing on our statistical tests and try to find exactly what matched their observations."
Statistical analysis of day-to-day temperatures at Baker Lake, Nunavut, showed that in May and June the persistence of temperature had recently declined, matching Inuit reports of greater unpredictability at that season. "People hadn't previously looked at persistence in this way," said CIRES fellow Roger Barry, also director of the World Data Center for Glaciology at the National Snow and Ice Data Center at CU-Boulder and a study co-author along with Gearheard.
What they found was a scientific story more in line with what people were witnessing on the ground. Weather along the Arctic latitudes was behaving more unpredictably than in other parts of the world.
"That's an incredibly important parameter to care about," said Weatherhead. "The way I try to describe it to some people is if we get an inch of rain out at my house in the month of July, I don't need to turn on the sprinklers. But if we get an inch of rain on July 1, and no rain after that, my lawn is dead.
"Ecosystems have evolved under a certain type of pattern. So if that is changing, that could be just as important as a small increase in temperature or some of the other changes we're talking about," Weatherhead said.
The new study helps scientists refine and test climate models, while also providing such models with a new category of information to consider, said Weatherhead. And Gearheard's work with the Inuit is demonstrating the value of indigenous environmental knowledge to modern climate science.
"When we first started talking about this, indigenous knowledge didn't have the place it does now in research," Gearheard said. "It's growing. People are becoming more familiar with it, more respectful of it."
Weatherhead and Gearheard said they are intrigued by the insights that incorporate indigenous knowledge and climate studies, but they don't want to stop there. The new study has sparked an interest in the type of environmental knowledge other communities could provide to climate scientists, from ranchers and farmers to indigenous groups. "When you treat these perspectives as different forms of evidence or knowledge and see where that takes you, that is when exciting stuff happens," said Gearheard.
The study appears this month in the journal Global Environmental Change. The National Science Foundation and the Social Sciences and Humanities Research Council of Canada provided funding for the study.

Weatherhead et al. Changes in weather persistence: Insight from Inuit knowledge. Global Environmental Change, 2010; DOI: 10.1016/j.gloenvcha.2010.02.002

High Arctic Species on Thin Ice

A new assessment of the Arctic's biodiversity reports a 26 per cent decline in species populations in the high Arctic.Populations of lemmings, caribou and red knot are some of the species that have experienced declines over the past 34 years, according to the first report from The Arctic Species Trend Index (ASTI), which provides crucial information on how the Arctic's ecosystems and wildlife are responding to environmental change.While some of these declines may be part of a natural cycle, there is concern that pressures such as climate change may be exacerbating natural cyclic declines.In contrast, population levels of species living in the sub-Arctic and low Arctic are relatively stable and in some cases, increasing. Populations of marine mammals, including bowhead whales found in the low Arctic, may have benefited from the recent tightening of hunting laws. Some fish species have also experienced population increases in response to rising sea temperatures."Rapid changes to the Arctic's ecosystems will have consequences for the Arctic that will be felt globally. The Arctic is host to abundant and diverse wildlife populations, many of which migrate annually from all regions of the globe. This region acts as a critical component in the Earth's physical, chemical, and biological regulatory system," says lead-author Louise McRae from the Zoological Society of London (ZSL).Data collected on migratory Arctic shorebirds show that their numbers have also decreased. Further research is now needed to determine whether this is the result of changes in the Arctic or at other stopover sites on their migration.Louise McRae adds: "Migratory Arctic species such as brent goose, dunlin and turnstone are regular visitors to the UK's shores. We need to sit up and take notice of what's happening in other parts of the world if we want to continue to experience a diversity of wildlife on our own doorstep."The ASTI includes almost 1,000 datasets on Arctic species population trends, including representation from 35 per cent of all known vertebrate species found in the Arctic.Co-author Christoph Zöckler from the UNEP-World Conservation Monitoring Centre says: "The establishment of these results comes at a crucial time for finding accurate indicators to monitor global biodiversity as governments strive to meet their targets of reducing biodiversity loss."The findings of the first ASTI report will be presented at the 'State of the Arctic' Conference in Miami, USA. The full report will be available to download from http://www.asti.is/ on Wednesday 17th March, 2010.

Surprise Shrimp Under Antarctic Ice

At a depth of 600 feet beneath the West Antarctic ice sheet, a small shrimp-like creature managed to brighten up an otherwise gray polar day in late November 2009.

This critter is a three-inch long Lyssianasid amphipod found beneath the Ross Ice Shelf, about 12.5 miles away from open water.
NASA scientists were using a borehole camera to look back up towards the ice surface when they spotted this pinkish-orange creature swimming beneath the ice.

Trek to gauge carbon's impact on Arctic sealife

Two teams of explorers and scientists are on their way to the Arctic for the first international project to measure the amount of carbon dioxide in water beneath the ice.Three British explorers will be airlifted to a remote location in the Arctic Ocean to start a 50-day trek towards the geographic North Pole in temperatures as low as minus 75 degrees Celsius, including wind chill.A second team of international experts on ocean acidification will be working from a temporary ice base on Ellef Ringnes Island, on the edge of the Arctic Ocean near the Canadian coast.Both teams will be drilling into the ice to collect water samples used to measure the amount of carbon dioxide in the water at various depths, according to the director of the Catlin Arctic Survey, arctic explorer Pen Hadow.Read more about the explorers' challenge"There is very little if any information about to what extent increasing levels of carbon dioxide in recent times has acidified the waters under the ice," Hadow said.Oceans are believed to absorb around one third of the CO2 in the atmosphere, according to the Fourth Assessment report from the Intergovernmental Panel on Climate Change (IPCC).Ocean acidification refers to the increasing acidity of sea water as carbon dioxide is absorbed from the earth's atmosphere. The ocean's acidity is measured by its pH level, which since 1750 has dropped by 0.1 units, according to the IPCC report.Some scientists believe the ice acts as a cap that prevents carbon dioxide being absorbed into the water. Others believe carbon dioxide is able to move through pores in the ice into the water.Part of the team's research will include the permeability of sea ice to carbon dioxide and the likely impact the thawing of large areas of ice will have on future CO2 levels in the sea.The last time the Catlin Arctic Survey team ventured into the Arctic, in 2009, they measured ice thickness and concluded that ice could stop forming over the Arctic Ocean during summer in as little as 20 years."The sea ice is looking like it's not going to be a year round feature in the next 20 or 30 years. So the lid is coming off an ocean which is suddenly able to absorb carbon dioxide in a way that it hasn't been able to before," Hadow said.This year's expedition will also test the likely impact of rising carbon dioxide levels on microscopic sea life.Zooplankton and phytoplankton will be exposed to levels of CO2 that some scientists say could be present in the oceans by 2100 if the world keeps emitting carbon dioxide at current levels."The prediction is that shell-based organisms will start to lose these shells because you're creating more carbonic acid in the water," said the survey's science manager, Dr Tim Cullingford.A research paper published in the Nature Geoscience earlier this month suggested that oceans are acidifying at their fastest rate in 65 million years.Researchers from Bristol University compared the current rate of acidification to a sudden rise in temperatures at the Paleocene-Eocene boundary.Then, surface ocean temperatures rose by up to six degrees Celsius within a few thousand years causing "widespread extinction" of organisms living deep down on the ocean floor."The widespread extinction of these ocean floor organisms during the Paleocene-Eocene greenhouse warming and acidification event tells us that similar extinctions in the future are possible," said the paper's lead author, Dr. Andy Ridgwell.The report said laboratory tests showed that lower pH levels in the sea could result in the dissolution of shells, slower growth, muscle wastage and dwarfism which could have knock-on effects on the whole ecosystem.The scientists at the Catlin Arctic Survey ice base will include experts from Plymouth Marine Laboratory, the European Project on Ocean Acidification (EPOCA), Université Pierre et Marie Curie-Paris 6, Villefranche and Fisheries and Oceans Canada.On their return in late April, the data will be distributed to about 13 organizations for examination worldwide.

Scientists vacuum up the data on dust

While most people give it the brushoff, a panel of scientists gathered Friday to focus on dust. Dust in the air. Dust in the oceans. Dust in your lungs. Good dust. Bad dust. And not a can of Pledge in sight.The scene, a conference room at the annual meeting of the American Association for the Advancement of Science in usually sunny Southern California, the land where recent wildfires filled the air with smoke and dust.Some researchers found fault with dust - "geotoxicology" Geoffrey S. Plumlee of the U.S. Geological Survey calls it.But turns out dust can fertilize land and the ocean, aiding some types of sea life.While it seems climate changes affect the amount of dust in the air, the effect of dust on climate change is less clear.And historical studies indicate that ice ages were surprisingly dusty.On the down side, Plumlee reports that the air you breathe can have a "breathtaking" array of particles in it.The soil fungus that causes valley fever in the Southwest, for example, is carried in windblown dust. And increases in dust in the air lead to higher rates of hospital admissions for things like asthma, he added.Other bad effects can range from increased heart attack risk to cancers and scarring of the lungs.Most public health focus has been on particulates from human sources, such as from combustion of fossil fuels, but there is increasing attention to potential health effects from dust from such sources as volcanic ash or of smoke and ash from wildfires, he said.Daniel R. Muhs, also from the Geological Survey, disclosed that studies of ocean sediments and Antarctic ice shows that ice ages were even dustier than today.Glaciers are major producers of dust by grinding over rocks, he explained. Muhs pointed out that water flowing from beneath glaciers is often milky from the dust enclosed, not clear. In addition, he said, glacial periods were drier and thus places like Africa had less vegetation and the wind could stir up more dust.Speaking of African dust, it may be beneficial by fertilizing regions such as the Amazon basin, said Oliver Chadwick of the University of California, Santa Barbara. Even Hawaii, one of the world's least dusty places, has forests fertilized by blown-in dust, he said.Dust is largely generated in deserts and their fringe, but also where agriculture opens soil to the wind and good topsoil can blow away, Chadwick said.That's what happened in the United States Dust Bowl of the 1930s.Joseph M. Prospero of the University of Miami who claimed to have been collecting dust longer than anyone on the panel, reported that the frequency of Africa dust arriving there today is higher than in the past.Ten to 20 times a year the Environmental Protection Agency standards for dust in the air are exceeded in South Florida and the Caribbean, he said.Dust can have a variety of impacts including fertilizing the ocean with iron, added Natalie Mahowald of Cornell University in Ithaca, N.Y."These particles can be carried for thousands of miles in the atmosphere, and during that time can interact with chemistry, clouds and radiation to modify climate," she said in prepared remarks.Dust can be both good and bad, concluded Muhs, threatening health yet fertilizing land and ocean. It also affects the Earth's radiation, which is currently undergoing a warming due to human-induced gases being added to the atmosphere.Over dark surfaces that absorb heat from the sun dust can have a cooling effect by reflecting light, but it can also warm other areas.In the end, the answer is blowing in the wind, said panel moderator Tim Radford, former science editor of The Guardian newspaper in England, quoting Bob Dylan.

Arctic Could Face Warmer and Ice-Free Conditions

There is increased evidence that the Arctic could face seasonally ice-free conditions and much warmer temperatures in the future.

Scientists documented evidence that the Arctic Ocean and Nordic Seas were too warm to support summer sea ice during the mid-Pliocene warm period (3.3 to 3 million years ago). This period is characterized by warm temperatures similar to those projected for the end of this century, and is used as an analog to understand future conditions.
The U.S. Geological Survey found that summer sea-surface temperatures in the Arctic were between 10 to 18°C (50 to 64°F) during the mid-Pliocene, while current temperatures are around or below 0°C (32°F).
Examining past climate conditions allows for a true understanding of how Earth's climate system really functions. USGS research on the mid-Pliocene is the most comprehensive global reconstruction for any warm period. This will help refine climate models, which currently underestimate the rate of sea ice loss in the Arctic.
Loss of sea ice could have varied and extensive consequences, such as contributions to continued Arctic warming, accelerated coastal erosion due to increased wave activity, impacts to large predators (polar bears and seals) that depend on sea ice cover, intensified mid-latitude storm tracks and increased winter precipitation in western and southern Europe, and less rainfall in the American west.
"In looking back 3 million years, we see a very different pattern of heat distribution than today with much warmer waters in the high latitudes," said USGS scientist Marci Robinson. "The lack of summer sea ice during the mid-Pliocene suggests that the record-setting melting of Arctic sea ice over the past few years could be an early warning of more significant changes to come."
Global average surface temperatures during the mid-Pliocene were about 3°C (5.5°F) greater than today and within the range projected for the 21st century by the Intergovernmental Panel on Climate Change.

Melting Tundra Creating Vast River of Waste Into Arctic Ocean

The increase in temperature in the Arctic has already caused the sea-ice there to melt. According to research conducted by the University of Gothenburg, if the Arctic tundra also melts, vast amounts of organic material will be carried by the rivers straight into the Arctic Ocean, resulting in additional emissions of carbon dioxide.

Several Russian rivers enter the Arctic Ocean particularly in the Laptev Sea north of Siberia. One of the main rivers flowing into the Laptev Sea is the Lena, which in terms of its drainage basin and length is one of the ten largest rivers in the world. The river water carries organic carbon from the tundra, and research from the University of Gothenburg shows that this adds a considerable amount of carbon dioxide to the atmosphere when it is degraded in the coastal waters.
Increased temperatures
The increase in temperature in the Arctic, which has already made an impact in the form of reduced sea-ice cover during the summer, may also cause the permafrost to melt. "Large amounts of organic carbon are currently stored within the permafrost and if this is released and gets carried by the rivers out into the coastal waters, then it will result in an increased release of carbon dioxide to the atmosphere," says Sofia Hjalmarsson, native of Falkenberg and postgraduate student at the Department of Chemistry.
Study of two areas
In her thesis, Sofia Hjalmarsson has studied the carbon system in two different geographical areas: partly in the Baltic Sea, the Kattegat and the Skagerrak, and partly in the coastal waters north of Siberia (the Laptev Sea, the East Siberian Sea and the Chukchi Sea). The two areas have in common the fact that they receive large volumes of river water containing organic carbon and nutrients, mainly nitrogen.
The thesis Carbon Dynamics in Northern Marginal Seas was publicly defended on 18 December.

Tipping Elements in the Earth System

A Special Feature of the Proceedings of the National Academy of Sciences presents the latest scientific insights on so-called tipping elements in the planetary environment. These elements have been identified as the most vulnerable large-scale components of the Earth System that may be profoundly altered by human interference. If one or more of those components is tipped -- especially in the course of global warming -- then the age of remarkably stable environmental conditions on Earth throughout the Holocene may end quickly and irreversibly.

This Special Feature was designed and edited by Hans Joachim Schellnhuber of the Potsdam Institute for Climate Impact Research (PIK). It is meant to make a major contribution to the emerging field of sustainability science. The authors involved analyse altogether eight Earth System components. Three of them, the biggest dust source on our planet, oceanic biogeochemical cycles, and marine methane hydrates, are discussed in depth as potential tipping elements for the first time ever.

"It is the cardinal question of Earth System and sustainability science whether global warming actually triggers singular transformations of crucial components of the planetary machinery," says Schellnhuber. Singular transformations -- as opposed to smooth linear and nonlinear ones -- would dramatically alter the environment in which human civilisations have developed and thrived over many millennia. "Currently, the climate system still operates in the Holocene mode, but the research presented here underlines that a rise of the global mean temperature beyond two degrees Celsius might push the world into singular-change terrain and therefore needs to be avoided," Schellnhuber adds.

The PIK scientist has introduced the tipping-elements concept into the research community some ten years ago. It describes components of the Earth System that could be pushed past critical thresholds by anthropogenic forcing, so that they may "tip" into qualitatively different modes of operation. In a recent seminal paper, Tim Lenton from the University of East Anglia, Hans Joachim Schellnhuber and an international group of colleagues presented a formal definition and compiled a short-list of the nine tipping elements ranked as the most policy-relevant. The current Special Feature examines five of these in much more depth: the El Niño/Southern Oscillation phenomenon, Arctic sea-ice and the great polar ice sheets, the Amazon rainforest, the major monsoon systems, and the circulation of ocean currents in the Atlantic Ocean.

In their article, Matthias Hofmann and Stefan Rahmstorf, also from PIK, discuss the last topic, i.e. the stability properties of the Atlantic Meridional Overturning Circulation (AMOC). The authors present new model simulations of the AMOC response to increased freshwater inflow into the North Atlantic. These challenge the hypothesis that the resulting circulation weakening and the possibility of abrupt oceanic change are just artefacts arising from model flaws. Rather, improving the physical realism of the model leads to a greater vulnerability of the projected AMOC stability.

A group of PIK scientists led by Anders Levermann show that every monsoon circulation inherently bears the possibility of an abrupt collapse. The reason is the moisture-advection feedback which is the core of any monsoon system and was captured in a conceptual model by the authors. The monsoon rains are essential for agriculture as the source of livelihood for several hundred million people in the pertinent regions, the authors state.

David Archer from the University of Chicago and his co-authors provide evidence that methane hydrates in ocean sediments should be regarded as a "slow tipping element" in the Earth's climate system. Global warming of some three degrees Celsius could lead to the escape of more than half of the relevant methane stocks, estimated 940 billion tons of carbon, on a millennial time-scale. This hydrate leakage could cause an additional rise in planetary temperature by 0.5 degrees Celsius. The authors tie this increase in global mean temperature to the methane, but it would persist through many millennia because methane is oxidised in about a decade to carbon dioxide, which continues to impact climate for many millennia.

Ulf Riebesell and colleagues from the Leibniz Institute of Marine Sciences (IFM-GEOMAR) describe the oceans as a climate-system component which is presently undergoing major changes. The sea is not only warming, it is also becoming more acidic. Unbridled anthropogenic emissions of greenhouse gases could alter the cycling of carbon and nutrients in the surface ocean and might damage entire marine ecosystems. The authors conclude that the current level of knowledge allows no clear answer on whether tipping points in the marine ecosphere exist, but they regard some of the projected shifts in oceanic biogeochemistry and their impacts as severe.

Mojib Latif and Noel Keenlyside, also of IFM-GEOMAR, present a review of the complicated mechanisms ruling the El Niño/Southern Oscillation (ENSO) phenomenon. It leads to strong temperature and precipitation fluctuations in the Equatorial Pacific from one year to another and has widespread effects on the global climate system. However, current climate models cannot capture the potential tipping point behaviour of the ENSO phenomenon, the authors resume. Given the potentially huge impacts on biological, chemical and socio-economic systems, the question whether global warming will fundamentally alter the ENSO dynamics in the future has to be investigated further.

A research team led by Richard Washington from the University of Oxford qualifies the biggest dust source on our planet, the Bodélé Depression in Chad, as a potential tipping element. This area in the southern Sahara releases huge plumes, which carry about 700,000 tons of dust towards the Atlantic and the Amazon basin. The authors explain that the so-deployed mineral aerosols play a vital role in transcontinental climatic and biophysical feedbacks. If regional wind patterns or surface erosivities changed due to anthropogenic interference, the dust export from the Bodélé Depression could be substantially modified at time scales as small as one season.

A research team headed by Yadvinder Malhi, also of the University of Oxford, has employed nineteen different global climate models to investigate, whether climate change could cause a large-scale dieback of Amazonian rainforest. The analysis based on a scenario with continuously increasing global emissions of greenhouse gases over the 21st century suggests that dry season water stress is likely to increase in parts of Amazonia. The researchers provide evidence that the Amazonian rainforest could reveal characteristic properties of a tipping element with the tendency to change into a seasonal forest.

In his paper on potential threshold behaviour of sea-ice and continental ice-sheets, Dirk Notz of the Max Planck Institute for Meteorology concludes that tipping points more likely exist for the loss of the Greenland ice sheet and the West-Antarctic ice sheet than for the loss of Arctic sea-ice, which could recover rapidly in a cooler climate. Inland ice could be much more vulnerable to regional warming due to the lack of large internal stabilizing feedbacks as existing for the Arctic sea-ice dynamics. Melting of the continental ice-sheets could lead to rapid multi-meter rise in mean sea level over the coming centuries.

Finally, Nobel Laureate Mario Molina and his co-authors demand fast action from political and economic decision makers to avoid activation of tipping elements. They propose to strengthen the Montreal Protocol regarding substances that have high global-warming potentials. In particular, the scientists make strong cases for an accelerated phasing out of hydrochlorofluorocarbons and a massive reduction of the emissions of soot.

"After two decades of failed climate protection since the 1990 IPCC Report it is more doubtful than ever whether society will manage to confine global environmental change to sub-dangerous levels," says Hans Joachim Schellnhuber. The tipping-elements field is developing quickly into a broad and relevant research frontier domain, but the issues pose tough challenges for contemporary science. Practically none of the planetary cases studied can be either dismissed now -- by firmly ruling out a possible anthropogenic triggering of irregular dynamics -- or settled by providing reliable estimates for activation temperatures and reaction time scales. "Many of the papers sketch the research way forward, but it seems that we will have to live with at least another decade of tantalising ignorance concerning the most worrying potential impacts of global warming," says Schellnhuber.

Potsdam Institute for Climate Impact Research (PIK), via AlphaGalileo

Journal Reference:

Hans Joachim Schellnhuber. Tipping Elements in Earth Systems Special Feature: Tipping elements in the Earth System. PNAS, December 7, 2009 DOI: 10.1073/pnas.0911106106


Icebergs breaking off from the Dawes Glacier in the Endicott Arm. (Credit: iStockphoto/Joseph Gareri)

Portions of Arctic Coastline Eroding, No End in Sight, Says New Study

The northern coastline of Alaska midway between Point Barrow and Prudhoe Bay is eroding by up to one-third the length of a football field annually because of a "triple whammy" of declining sea ice, warming seawater and increased wave activity, according to new study led by the University of Colorado at Boulder.

The conditions have led to the steady retreat of 30 to 45 feet a year of the 12-foot-high bluffs -- frozen blocks of silt and peat containing 50 to 80 percent ice -- which are toppled into the Beaufort Sea during the summer months by a combination of large waves pounding the shoreline and warm seawater melting the base of the bluffs, said CU-Boulder Associate Professor Robert Anderson, a co-author on the study. Once the blocks have fallen, the coastal seawater melts them in a matter of days, sweeping the silty material out to sea.

Anderson, along with collaborators Cameron Wobus of Stratus Consulting and Irina Overeem of CU's Institute of Arctic and Alpine Research, or INSTAAR, each presented results from components of their study at the annual meeting of the American Geophysical Union in San Francisco held Dec. 14-18.

The problem is caused by several factors, including increased erosion along the Alaskan coastline due to longer ice-free summer conditions and warmer seawater bathing the coast, Anderson said. The third potential factor is that the longer the sea ice is detached from the coastline, the further out to sea the sea-ice edge will be. This open-ocean distance between the sea ice and the shore, known as the "fetch," increases both the energy of waves crashing into the coast and the height to which warm seawater can come into contact with the frozen bluffs, said Anderson.

"What we are seeing now is a triple whammy effect," said Anderson. "Since the summer Arctic sea ice cover continues to decline and Arctic air and sea temperatures continue to rise, we really don't see any prospect for this process ending."

In addition to Wobus and Overeem, co-authors on the studies include Gary Clow and Frank Urban of the U.S. Geological Survey in Lakewood, Colo., and Tim Stanton of the Naval Postgraduate School in Monterey, Calif.

The shoreline bluffs are made up of contiguous, polygon-shaped blocks, primarily made of permafrost and each roughly 70 to 100 feet across, he said. Ice "wedges" created by seeping summer surface water that annually freezes and thaws are driven deeper and deeper into the cracks between individual blocks each year. The blocks closest to the sea are undermined as warm seawater melts their base, and eventually split apart from neighboring blocks and topple during stormy conditions, said Anderson.

The researchers used a variety of instruments and methods in the study to examine the dynamic transition between the land and the sea, including time-lapse photography of shoreline erosion, global positioning systems (GPS), meteorological measurements including temperature and wind speed, and sediment analyses of the coastal bluffs. Offshore measurements included sea-ice distribution, ocean floor depth, sea-surface temperatures and wave dynamics, said Anderson, also a fellow at INSTAAR.

The time-lapse images were taken with four tripod mounted "game cameras" often used by hunters and wildlife biologists and which were set up parallel to the shoreline. The cameras snapped pictures every six hours during the 24-hour summer daylight months to track the effects of the waves on the coastline, said Anderson.

"Once one of these blocks topples, the process continues on to the next block," Anderson said. "These images are very powerful, because they pick up activity during severe storms when we aren't there to watch." The images also illustrate the steady melting along the water's edge that helps to undermine the bluffs even in the absence of storm activity.

The research team also deployed four submerged ocean buoys attached to metal sleds with sensors to measure the wave activity at different depths in the shallow coastal waters, comparing wave power with the shoreline fetch. The team attached temperature sensors to the buoy mooring lines to monitor seawater temperatures, which have been warming in recent summers due to increased solar radiation, he said.

When the sea ice is further from the shore, currents from the Beaufort and Chukchi seas transport warmer water to the coastline, said Anderson. While the temperature hovers around 45 degrees during the summer months, the shallow coastal water warmed to as much as 59 degrees during the 2007 field season -- the same year the largest loss of summer Arctic sea was recorded, he said.

As the ice wedges cut down through the polygon blocks, the surface soil above them -- which thaws each summer -- is pushed up slightly, forming small ridges that eventually surround each polygon, said Anderson. Small ponds form above individual polygons during the summer months as the surface ice and snow melts, providing habitat for migrating birds that feed and breed along the Beaufort Sea coastline.

"This is an important habitat for birds and other wildlife," said Anderson. "One of the concerns we have is that some larger ponds and lakes located slightly further inland may begin draining into the sea as the shoreline continues to recede."

While there are no towns adjacent to the specific study area, coastal erosion threatens abandoned military and petroleum infrastructure, he said. Coastal erosion occurs at similar sites elsewhere along Alaska's coastline. Bank stabilization measures using sandbags, for example, have been undertaken at the Alaskan town of Kaktovik on the Beaufort Sea in an attempt to slow the problem.

According to a 2009 CU-Boulder study, Arctic sea ice during the annual September minimum is now declining at a rate of 11.2 percent per decade. Only 19 percent of the ice cover was more than two years old -- the least ever recorded in the satellite record and far below the 1981-2000 summer average of 48 percent.

How Arctic Food Webs Affect Mercury in Polar Bears

With growing concerns about the effects of global warming on polar bears, it's increasingly important to understand how other environmental threats, such as mercury pollution, are affecting these magnificent Arctic animals.New research led by biogeochemists Travis Horton of the University of Canterbury and Joel Blum of the University of Michigan lays the groundwork for assessing current and future effects of mercury deposition and climate change on polar bears.The study appears in the December issue of the journal Polar Research.Mercury is a naturally occurring element, but some 150 tons of it enter the environment each year from human-generated sources such as coal-burning power plants, incinerators and chlorine-producing plants. Deposited onto land or into water, mercury is picked up by microorganisms, which convert some of it to methylmercury, a highly toxic form that builds up in fish and the animals that eat them. As bigger animals eat smaller ones, the methylmercury is concentrated -- a process known as bioaccumulation. Sitting at the top of the food chain, polar bears amass high concentrations of the contaminant.Although that much is known, the details of how mercury moves through different food webs -- particularly in the Arctic, where snow and ice contribute to mercury deposition -- are not well understood. To tease out that information, Horton, Blum and co-workers studied polar bear hair samples from museum specimens collected in the late 19th and early 20th centuries, before mercury emissions from human-generated sources began to escalate.By looking at three chemical signatures -- nitrogen isotopes, carbon isotopes and mercury concentrations -- the researchers learned that polar bears get their nutrition (and mercury) from two main food webs. At the base of one web are microscopic plants that float on the surface of the ocean (known as phytoplankton). The foundation of the second web is algae that live on sea ice.The study showed that polar bears that get most of their nutrition from phytoplankton-based food webs have greater mercury concentrations than those that participate primarily in ice algae-based webs.While it's tempting to speculate that declining sea ice, due to global warming, may force polar bears to depend more on phytoplankton-based webs, thus increasing their mercury exposure, the study doesn't directly address that issue. It does, however, provide other useful information, said Blum, who is the John D. MacArthur Professor of Geological Sciences and a professor of ecology and evolutionary biology."If you want to understand the potential effects of changing ecosystems on polar bears, you need to be aware of the existence of these two food webs, which may possibly be affected by sea ice," Blum said. "This work provides background information that will be important in our in-depth understanding of mercury bioaccumulation in polar bears."In addition to Horton and Blum, the paper's authors are Zhouqing Xie, who was at U-M when the research was done and now is at the University of Science and Technology of China; Michael Hren, who was at Yale University when the work was done and now is a postdoctoral fellow at U-M; and C. Page Chamberlain of Stanford University.University of Michigan

Changing Arctic Affecting Air, Ocean, And Everything In Between

Despite the fact that summer 2009 had more sea ice than in 2007 or 2008, scientists are seeing drastic changes in the region from just five years ago and at rates faster than anticipated. The findings were presented October 22 in the annual update of the Arctic Report Card, a collaborative effort of 71 national and international scientists.

"The Arctic is a special and fragile place on this planet," said Jane Lubchenco, Ph.D., under secretary for oceans and atmosphere and NOAA administrator. "Climate change is happening faster in the Arctic than any other place on Earth -- and with wide-ranging consequences. When I visited the northern corners of Alaska's Arctic region earlier this year, I saw an area abundant with natural resources, diverse wildlife, proud local and native peoples -- and a most uncertain future. This year's Arctic Report Card underscores the urgency of reducing greenhouse gas pollution and adapting to climate changes already under way."
Among the changes highlighted in the 2009 update to the report card were:
A change in large scale wind patterns affected by the loss of summer sea ice,
The replacement of multi-year sea ice by first-year sea ice,
Warmer and fresher water in the upper ocean linked to new ice-free areas,
A continued loss of the Greenland ice sheet,
Less snow in North America and increased runoff in Siberia, and
The effect of the loss of sea ice on Arctic plant, animal, and fish species.
Scientific assessments are key to informing our understanding of climate -- how and why it is changing and what the changing conditions mean to lives and livelihoods. The Arctic Report Card established a baseline of conditions in the region at the beginning of the 21st century and the annual updates track and monitor the often quickly-changing conditions in the Arctic. Using a color-coding system of red to indicate consistent evidence of warming and yellow to indicate there are mixed signals about warming from climate indicators and species, the report card is updated annually in October and tracks Arctic data in six categories: atmosphere, sea ice, biology, ocean, land, and conditions in Greenland.
"The Arctic we see today is very different from the Arctic we saw even five years ago," said Jackie Richter-Menge of the USACE Cold Regions Research and Engineering Laboratory in Hanover, N.H. and the report's chief technical editor and contributing author. "It's a warmer place with less thick and more mobile sea ice, warmer and fresher ocean water, and increased stress on caribou, reindeer, polar bears and walrus in some regions."
The 2009 update to the report card reflects the contributions of an international team of 71 researchers from countries that include the United States of America, Canada, Belgium, China, Denmark, Japan, The Netherlands, Russia, and the United Kingdom.
The Report Card can be found at http://www.arctic.noaa.gov/reportcard
Adapted from materials provided by National Oceanic and Atmospheric Administration.

Arctic Has Potential To Alter Earth's Climate: Arctic Land And Seas Account For Up To 25 Percent Of World's Carbon Sink

In a new study in the journal Ecological Monographs, ecologists estimate that Arctic lands and oceans are responsible for up to 25 percent of the global net sink of atmospheric carbon dioxide. Under current predictions of global warming, this Arctic sink could be diminished or reversed, potentially accelerating predicted rates of climate change.

In their review paper, David McGuire of the U.S. Geological Survey and the University of Alaska at Fairbanks and his colleagues show that the Arctic has been a carbon sink since the end of the last Ice Age, which over time has accounted for between zero and 25 percent, or up to about 800 million metric tons, of the global carbon sink. On average, says McGuire, the Arctic accounts for 10-15 percent of the Earth's carbon sink. But the rapid rate of climate change in the Arctic – about twice that of lower latitudes – could eliminate the sink and possibly make the Arctic a source of carbon dioxide.
Carbon generally enters the oceans and land masses of the Arctic from the atmosphere and largely accumulates in permafrost, the frozen layer of soil underneath the land's surface. Unlike active soils, permafrost does not decompose its carbon; thus, the carbon becomes trapped in the frozen soil. Cold conditions at the surface have also slowed the rate of organic matter decomposition, McGuire says, allowing Arctic carbon accumulation to exceed its release.
But recent warming trends could change this balance. Warmer temperatures can accelerate the rate of surface decomposition, releasing more carbon into the atmosphere. More concerning, says McGuire, is that the permafrost has begun to thaw, exposing previously frozen soil to decomposition and erosion. These changes could reverse the historical role of the Arctic as a sink for carbon.
"In the short term, warming temperatures could expose more Arctic carbon to decomposition," says McGuire. "And with permafrost melting, there will be more available carbon to decompose."
On the scale of a few decades, the thawing permafrost could also result in a more waterlogged Arctic, says McGuire, a situation that could encourage the activity of methane-producing organisms. Currently, the Arctic is a substantial source of methane to the atmosphere: as much as 50 million metric tons of methane is released per year, in comparison to the 400 million metric tons of carbon dioxide the Arctic sequesters yearly. But methane is a very potent greenhouse gas – about 23 times more effective at trapping heat than carbon dioxide on a 100-year time scale. If the release of Arctic methane accelerates, global warming could increase at much faster rates.
"We don't understand methane very well, and its releases to the atmosphere are more episodic than the exchanges of carbon dioxide with the atmosphere," says McGuire. "It's important to pay attention to methane dynamics because of methane's substantial potential to accelerate global warming."
But uncertainties still abound about the response of the Arctic system to climate change. For example, the authors write, global warming may produce longer growing seasons that promote plant photosynthesis, which removes carbon dioxide from the atmosphere; however, increasingly dry conditions may might counteract and overcome this effect. Similarly, dry conditions can lead to increased fire prevalence, releasing even more carbon.
McGuire contends that only specific regional studies can determine which areas are likely to experience changes in response to climate change.
"If the response of the arctic carbon cycle to climate change results in substantial net releases of greenhouse gases, this could compromise mitigation efforts that we have in mind for controlling the carbon cycle," he says.
This study was sponsored by the Arctic Monitoring and Assessment Program, the Climate in the Cryosphere Program, and the International Arctic Science Committee.
Adapted from materials provided by Ecological Society of America, via EurekAlert!, a service of AAAS.

High Numbers Of Heat-loving Bacteria Found In Cold Arctic Ocean

A team of scientists led by U of C grad Casey Hubert has detected high numbers of heat loving, or thermophilic, bacteria in subzero sediments in the Arctic Ocean off the Norwegian island of Spitsbergen. The bacterial spores might provide a unique opportunity to trace seepages of fluids from hot sub-seafloor habitats, possibly pointing towards undiscovered offshore petroleum reservoirs.

These thermophiles exist in the Arctic Ocean sediment as spores — dormant forms that withstand adverse conditions for long periods, waiting for better times. Experimental incubations at 40 to 60 degrees Celsius revive the Arctic spores, which appear to have been transported from deeper hot spots.
"The genetic similarities to bacteria from hot offshore oil reservoirs are striking," says Hubert. After completing his PhD in petroleum microbiology at University of Calgary, Hubert traveled to Bremen, Germany, with an NSERC post-doctoral fellowship to study the Arctic thermophiles at the renowned Max Planck Institute for Marine Microbiology. "We expect ongoing surveys will pin-point the source, or sources, of these misplaced microbes. This could have interesting applications if they are really coming up from leaky petroleum reservoirs."
Because these bacteria are anaerobic, their high abundance and steady supply into the sediments indicate they are coming from a huge oxygen-free habitat. Hubert says one source could be a deep pressurized oil reservoir from which upward-leaking hydrocarbons carry bacteria into overlying seawater. Another source could be related to fluid circulation through warm ocean crust at spreading ridges where "black smokers" and other hydrothermal vents are present. The thermophiles must be getting carried out of one of these abyssal hot spots and may be dispersed by ocean currents before ending up as hibernating spores in the cold sediments, where they were discovered.
"We hope further experiments and genetic forensics will reveal the warm source," adds Max Planck Director Prof. Bo Barker Jørgensen.
While the spores might provide an opportunity to track marine hot spots, they also offer fresh insight for understanding biodiversity and the "hidden rare biosphere." The dominant bacterial species in a given environment obscure many minor groups that don't seem to participate in ecosystem functioning. Dormant thermophiles in the cold ocean could be a useful model for understanding how biodiversity is maintained by the passive dispersal of small cells over great distances. "The Arctic thermophiles could hold important clues for solving broader riddles of bio-geography," says Hubert.
This research was supported by the Natural Sciences and Engineering Research Council of Canada, the Max Planck Society, the Austrian Science Fund, and the US National Science Foundation.
Journal reference:
Casey Hubert, Alexander Loy, Maren Nickel, Carol Arnosti, Christian Baranyi, Volker Brüchert, Timothy Ferdelman, Kai Finster, Flemming Mønsted Christensen, Júlia Rosa de Rezende, Verona Vandieken, and Bo Barker Jørgensen. A Constant Flux of Diverse Thermophilic Bacteria into the Cold Arctic Seabed. Science, September 18, 2009
Adapted from materials provided by University of Calgary.