Science & the Public: Sarah’s tale of Arctic warming

Observations from one remote village as its climate changesWeb edition : Thursday, October 20th, 2011 Recalling cooler timesSarah James brings stories of change affecting her Caribou People in Alaska.J. Raloff

MIAMI Sarah James remembers playing outdoors as a child even in the dead of winter. It often hit -70 degrees Fahrenheit, although not for prolonged periods. But she and the other kids, tired of being house-bound, just bundled up in snow suits and boots made from caribou skins. Even such frigid temps never put life — or play — on hold, recalls this 67-year-old resident of Arctic Village, Alaska.

Today, winter cold snaps seldom dip below -40 degrees, she says. And snows, that used to begin falling in August or September, now typically arrive in late October or November.

Over a half-century or so, her town of some 150 Athabascan Indians has watched as the formerly extreme but fairly predictable climate in this amazingly remote region of inland Alaska has become warmer and more erratic. Overall, that’s definitely not been a change for the better, James says.

She ventured to South Florida this week — and the Society of Environmental Journalists’ annual meeting — to describe what it’s like to weather life on the frontlines of climate change.

James grew up on a flat tundra range above the Arctic Circle. In her youth, the local vegetation was several inches to a few feet tall. And just inches down, the soil was permanently frozen. No more. Cottonwoods and willows have migrated in, sending up trunks 10 feet high or more. Understory shrubs followed. With the taller, woodier vegetation came an influx of bears and beavers.

That at least has brought some benefits, James claims. Like more meat. In her community with no running water, no agriculture to speak of and no roads, people still largely live off of the land. That means eating caribou, moose, ducks, fish and small mammals. Including beaver.

The villagers catch game whenever it’s available, then smoke it or freeze it for meals throughout the rest of the year. Arctic Village built a huge solar-powered municipal walk-in freezer during the 1970s, about 24 feet on a side. It circulated a fluid that was chilled as it ran through the frozen soil and then released that cold to keep the stored meats rock solid. But after two decades this cold locker had to be abandoned. The melting permafrost wasn’t keeping the chiller chilly enough. Today, James says, people use diesel-powered electricity to run home freezers. And it’s expensive, since that diesel fuel all arrives by plane.

Another byproduct of the melting permafrost: erosion of shorelines along lakes and creeks.

Always fairly drought-ridden, inland Alaska increasingly has also been plagued by fires — especially now that the invasion of trees had added extra tinder. Smoke associated with the fires can shut down air traffic through the area. And that can delay deliveries of fresh produce and fuel — or medical evacuations of the sick or injured. Arctic Village is one of the most remote spots in North America, James says. And the closest hospital, she notes, is in Fairbanks, a two-hour flight away.

For decades, scientists have been explaining that any global warming will be exaggerated in the polar regions, especially the Arctic. But reading about that in dry research papers and reports by the Intergovernmental Panel on Climate Change are quite different from listening to a woman describe how the norms of climate in her part of the world have been turned topsy turvy. “Sometimes in rains in January,” James says, “or snows in July. We just don’t know what to expect from one day to another,” she told me across the breakfast table this morning.

“We’re people of the caribou,” the quiet-voiced woman explains. “We believe our people were put on this Earth to protect our caribou.” And to date, she maintains, her Gwich’in tribe of some 8,000 individuals  —  spread across 15 villages in northeastern Alaska and northwestern Canada — think they’ve been managing pretty well.

In 1988, “our tribal elders came together to protect the coastal plain of the Arctic National Wildlife Refuge, the birthing ground of our caribou,” she says. Even back then, she says, “they were concerned about the many changes that were happening. They were talking about climate change and warming — and that’s one reason they organized against oil and gas development.”

Her community is still arguing against it. It’s also one themes James plans to talk about during an October 21 session, here, at the SEJ meeting about climate impacts on indigenous communities.

Found in: Climate Change, Environment and Science & Society

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Science & the Public: Arctic ozone: ‘Hole’ or just not whole?

Some scientists argue the far North’s ozone merely thinned.Web edition : Tuesday, October 4th, 2011 This past spring, the Arctic stratosphere’s ozone layer suffered unprecedented depletion. But whether the record loss constituted a “hole” depends on which experts you consult.

In a Nature paper published online earlier this week, Gloria Manney of NASA’s Jet Propulsion Laboratory in Pasadena and more than two dozen coauthors describe the 2011 loss as “an Arctic ozone hole.” Other renowned scientists have been weighing in — and some argue that as dramatic as this year's thinning was, a hole it wasn't.

Reports of a putative hole in the far North’s ozone are far from new. A quarter century ago to this day, Science News ran a story noting that “while everyone’s attention has been riveted on the atmosphere above Antarctica, a NASA researcher has discovered what he believes is another ozone cavity that forms each [winter] on the other side of the world. . . . This Arctic ozone hole is ‘not as large in magnitude, but it’s unquestionably there.'"

Since then, descriptions of the recurrent depletion of Arctic ozone have been scaled back to more of just a demonstrable thinning. There's been little question that its triggers, however, are identical to those that seasonably eat away huge portions of Antarctica’s stratospheric ozone.

What made 2011 different — and a watershed — argues Michelle Santee (a JPL colleague of Manney's and coauthor on the new paper), is that at long last, “the magnitude of the [Arctic] loss is comparable to that in the early Antarctic ozone holes in the mid 1980s.”

Santee observes that “the actual definition of an ozone hole has never been codified, even for the Antarctic.” Over the past several decades, however, a de facto rule of thumb has developed. It's measured in terms of the total ozone throughout a column of the atmosphere spanning from Earth’s surface up to satellite height. Such composite measurements are logged in Dobson units, and 220 is about the minimum needed to constitute a hole.

Ordinarily, Santee says, 450 Dobson units “is sort of the canonical value for the Northern polar region’s ozone — what would be your sort of basal level.” This year, she notes, total-column Arctic ozone values “were below 250 Dobson units for nearly a month — and reached 220 to 230 for about a week.”

Geir Braathen, senior scientific officer with the World Meteorological Organization in Geneva, concurs that “scientists have not agreed on any threshold ozone loss, like 250 or 260 Dobson units [for a hole].” Still, this atmospheric chemist cautions, “I would be careful about calling the Arctic depletion an ozone hole” because it might lead people to think it's comparable to what emerges in the Antarctic. And it isn’t.

Antarctica's hole recurs annually, whereas mega-thinning in Arctic ozone is novel. Antarctica’s ozone also thins at some point to zero in a band many kilometers high. At no altitude has Arctic ozone ever fallen to zero — even in 2011. Finally, Braathen points out, the aerial expanse and depth of the Antarctic hole greatly dwarfs the Arctic region that experienced substantial thinning earlier this year.

“Going into this Arctic spring, many of us — myself included — really thought this might be the year that we would see a real Arctic ozone hole,” observed Susan Solomon, of the University of Colorado, Boulder, at the recent American Chemical Society meeting in Denver. "But in the end," she says, "I think it’s fair to say that we didn’t.”

It may be a matter of semantics, she concedes, but there was a rapid resupply of ozone from outside the Arctic vortex (that swirling wall of winds in the stratosphere that largely corrals a patch of atmosphere, rendering it vulnerable to ozone-destroying chemical reactions). Such a resupply does not occur in the Antarctic vortex, she notes; and that's what permits its stratospheric ozone concentrations to plummet to zero over a several-kilometer height.

So, although the new paper clearly demonstrates that at some altitudes Arctic ozone was efficiently destroyed, Solomon says, “I wouldn’t call this an ozone hole.” 

Whatever you call 2011's Arctic ozone depletion, “I consider this to be a ‘big deal,’” says Ross Salawitch of the University of Maryland in College Park. Moreover, there’s no reason to suspect that in some future years, the losses won't be substantially worse, he says. 

Warming surface temperatures can cool the stratosphere, promoting conditions that accelerate ozone depletion, he notes. It takes prolonged cold temperatures in the winter and spring stratosphere to maximize ozone losses. Although such conditions have not been recurring annually in the Arctic, they have returned at three- to four-year intervals. And each new cold snap has been more extreme than the last, Salawitch points out.

Reinforcing concerns about future ozone depletion, Braathen says, is recognition that for many years to come there will be more than enough chlorine- and bromine-based pollutants in the stratosphere to allow for the possibility of “complete destruction of ozone — even in the Arctic — if it’s cold enough.”

Found in: Earth Science, Environment and Science & Society

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Arctic ozone loss in 2011 unprecedented

Record ozone depletion over the Arctic early this year rivals what was observed in the Antarctic when holes in the protective atmospheric layer first appeared there during the 1980s.

The observation raises concerns that portions of the Northern Hemisphere might periodically begin experiencing potentially harmful levels of ultraviolet radiation during early spring, an international team of scientists reports online October 2 in Nature.

“It was significantly worse than anything we have ever seen,” says Geir Braathen of the World Meteorological Organization in Geneva, who was not one of the authors of the Nature paper. Typically, spring Arctic ozone depletion has maxed out at a drop of between 20 and 30 percent, the atmospheric chemist notes. “But in 2011, we had a loss of around 40 percent.”

In Antarctica, 70 percent of the ozone can disappear in springtime, Braathen says. Within a 5- to 7-kilometer–thick band of the stratosphere, ozone concentrations actually plummet to zero, he says.

Arctic conditions have not gotten nearly that bad, says Michelle Santee of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., one of 29 authors of the new Arctic ozone analysis.

Although ozone can be found at any altitude over the Arctic, most accumulates between 14 to 21 kilometers up. There, concentrations hover around 4.5 parts per million much of the year. But in late March, “there was an approximately 2-kilometer altitude region where ozone fell to around 0.7 ppm,” Santee says — “meaning the ozone was pretty much gone.” In small regions, she adds, patches of the Arctic stratosphere saw ozone drop to 0.5 ppm.

It takes four things to destroy much of the stratosphere’s ozone: sunlight; very prolonged cold temperatures; a stable vortex of winds that prevents ozone losses inside it from being replenished with more from outside; and the presence of special clouds that foster the transformation of benign chlorine molecules into ozone-vanquishing types. For the first time in the Arctic, all of these conditions aligned for months, says JPL atmospheric scientist and coauthor Nathaniel Livesey, “making it the perfect storm.”

Although clearly anomalous, this year’s Arctic ozone loss could be the harbinger of worse things to come, comments Ross Salawitch of the University of Maryland in College Park. Although prolonged cold spells in the stratosphere hit only every few years, those in recent winters have been increasingly extreme, he says. There’s some concern that a progressive warming at Earth’s surface is responsible for cooling of the stratosphere, he says. The new Nature paper “sets the stage for asking: Is climate change playing a role?”

Found in: Earth and Environment

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Salt clouds relieve some Arctic warming

Sea spray creates a diffuse filter for the sun’s warming rays Web edition : Friday, April 22nd, 2011

Earth’s warming in recent years has had an exaggerated impact in the Arctic. There, temperatures have soared relative to temperate areas, resulting in an increased summer melting of sea ice. But new research indicates that the local warming would be even more dramatic if it weren’t for salt sprays kicked up by whitecaps from the Arctic’s increasingly open waters.

Snow and sea ice reflect much of the sun’s warming rays back into space. As an increasing share of the Arctic Ocean’s year-round cover of sea ice has disappeared, the sea surface has darkened — or reduced its albedo — and become an increasingly better absorber of solar energy. The open water starts to develop in spring and doesn’t ice over again until fall. Year-round ice is ice that survives the summer.

Clouds can deflect incoming solar rays. And climate scientists have realized that some of the salt from sea spray could enter the lower atmosphere, forming diffuse filtering clouds of tiny particles. The question had been how effectively these clouds might offset warming due to the Arctic Ocean’s diminishing summer albedo.

The majority of sea-salt particles emitted into the air are well under a micrometer in diameter, notes climate scientist Hamish Struthers of Stockholm University. These tiny particles, known as aerosols, can persist in the air for days or even weeks, he says, and rise to altitudes of a kilometer or more. For the new study, he and his colleagues input into a computer program satellite measurements of seasonal changes in the Arctic albedo and surface measurements of a host of features including temperatures, ice cover and sea salt kicked up by waves on the ocean surface.

As expected, the salt clouds can exert a subtle cooling of the Arctic, the team reports online April 13 in Atmospheric Chemistry and Physics. Struthers says his group’s new calculations indicate that “the size of this [salt] aerosol effect is most likely 10 percent or less of the albedo [warming] effect” due to sea-ice melting. The effect is small, he acknowledges, but not negligible.

“Natural feedbacks in the climate system, such as the one described here, are potentially very important,” says Natalie Mahowald, an atmospheric scientist at Cornell University. “This is the first time I have seen this feedback mechanism discussed or quantified,” she says, making it “an interesting paper that describes a new mechanism for modulating climate in the Arctic region.”

Found in: Earth, Environment and Matter & Energy

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Effects of climate change in Arctic more extensive than expected, report finds

ScienceDaily (May 4, 2011) — A much reduced covering of snow, shorter winter season and thawing tundra: The effects of climate change in the Arctic are already here. And the changes are taking place significantly faster than previously thought. This is what emerges from a new research report on the Arctic, presented in Copenhagen this week. Margareta Johansson, from Lund University, is one of the researchers behind the report.

Together with Terry Callaghan, a researcher at the Royal Swedish Academy of Sciences, Margareta is the editor of the two chapters on snow and permafrost.

"The changes we see are dramatic. And they are not coincidental. The trends are unequivocal and deviate from the norm when compared with a longer term perspective," she says.

The Arctic is one of the parts of the globe that is warming up fastest today. Measurements of air temperature show that the most recent five-year period has been the warmest since 1880, when monitoring began. Other data, from tree rings among other things, show that the summer temperatures over the last decades have been the highest in 2000 years. As a consequence, the snow cover in May and June has decreased by close to 20 per cent. The winter season has also become almost two weeks shorter -- in just a few decades. In addition, the temperature in the permafrost has increased by between half a degree and two degrees.

"There is no indication that the permafrost will not continue to thaw," says Margareta Johansson.

Large quantities of carbon are stored in the permafrost.

"Our data shows that there is significantly more than previously thought. There is approximately double the amount of carbon in the permafrost as there is in the atmosphere today," says Margareta Johansson.

The carbon comes from organic material which was "deep frozen" in the ground during the last ice age. As long as the ground is frozen, the carbon remains stable. But as the permafrost thaws there is a risk that carbon dioxide and methane, a greenhouse gas more than 20 times more powerful than carbon dioxide, will be released, which could increase global warming.

"But it is also possible that the vegetation which will be able to grow when the ground thaws will absorb the carbon dioxide. We still know very little about this. With the knowledge we have today we cannot say for sure whether the thawing tundra will absorb or produce more greenhouse gases in the future," says Margareta Johansson.

Effects of this type, so-called feedback effects, are of major significance for how extensive global warming will be in the future. Margareta Johansson and her colleagues present nine different feedback effects in their report. One of the most important right now is the reduction of the Arctic's albedo. The decrease in the snow- and ice-covered surfaces means that less solar radiation is reflected back out into the atmosphere. It is absorbed instead, with temperatures rising as a result. Thus the Arctic has entered a stage where it is itself reinforcing climate change.

The future does not look brighter. Climate models show that temperatures will rise by a further 3 to 7 degrees. In Canada, the uppermost metres of permafrost will thaw on approximately one fifth of the surface currently covered by permafrost. The equivalent figure for Alaska is 57 per cent. The length of the winter season and the snow coverage in the Arctic will continue to decrease and the glaciers in the area will probably lose between 10 and 30 per cent of their total mass. All this within this century and with grave consequences for the ecosystems, existing infrastructure and human living conditions.

New estimates also show that by 2100, the sea level will have risen by between 0.9 and 1.6 metres, which is approximately twice the increase predicted by the UN's panel on climate change, IPCC, in its 2007 report. This is largely due to the rapid melting of the Arctic icecap. Between 2003 and 2008, the melting of the Arctic icecap accounted for 40 per cent of the global rise in sea level.

"It is clear that great changes are at hand. It is all happening in the Arctic right now. And what is happening there affects us all," says Margareta Johansson.

The report "Impacts of climate change on snow, water, ice and permafrost in the Arctic" has been compiled by close to 200 polar researchers. It is the most comprehensive synthesis of knowledge about the Arctic that has been presented in the last six years. The work was organised by the Arctic Council's working group for environmental monitoring (the Arctic Monitoring and Assessment Programme) and will serve as the basis for the IPCC's fifth report, which is expected to be ready by 2014.

Besides Margareta Johansson, Torben Christensen from Lund University also took part in the work.

More information on the report and The Artic as a messenger for global processes - climate change and pollution conference in Copenhagen can be found at: http://amap.no/Conferences/Conf2011/

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Lund University.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

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