Jeremy Potter NOAA / OAR / OER

Scientists work on the ice in the Arctic under a midnight sun.

By Tia Ghose
LiveScience

Large swaths of the Arctic tundra will be warm enough to support lush vegetation and trees by 2050, a new study suggests.

Higher temperatures will lessen snow cover, according to the study, which is detailed in the March 31 issue of the journal Nature Climate Change. That, in turn, will decrease the sunlight reflected back into the atmosphere and increase warming. About half the areas will see vegetation change, and areas currently populated by shrubs may find woody trees taking their place.

More on warming from NBCNews.com:

Product picked from Greenland tundra

Arctic gets greener as climate warms up

"Substitute the snowy surface with the darker surface of a coniferous tree, and the darker surface stores more heat," said study co-author Pieter Beck, a vegetative ecologist at the Woods Hole Research Center in Massachusetts. "It's going to exacerbate warming."

Warming Arctic
The Arctic climate affects the world: Changes in sea ice affect ocean circulation, which, in turn, affects atmospheric circulation that then impacts the globe, said Bruce Forbes, a geographer at the Arctic Center at the University of Lapland in Finland, who was not involved in the study. [Images of Melt: Earth's Vanishing Ice]

Past research suggested that warming has already brought later winters and earlier springs to the Arctic. And fossil forests reveal the Arctic was once green as well.

To find out exactly how much greening Arctic warming would bring, the team used a model that projected how temperature changes would affect snow cover, vegetation and the increased evaporation and transpiration from plants in the Arctic.

Transformed tundra
The team found that at least half of the tundra would see changes in the plant types it supported by 2050. In addition, they found more than a 50 percent increase in how much woody greenery — such as coniferous trees — would populate the Arctic. The tree line would also shift north, with coniferous forests sprouting where shrubs once grew.

Most of the greening was driven by the loss of reflectivity, or albedo, from snow cover. With less snow to reflect heat back into the atmosphere and more dark trees, the Earth gets warmer, "just like a dark car gets hotter in a warm parking lot than a light car does," Beck told LiveScience.

That warmth supports more tree and shrub growth, creating a positive feedback cycle to the warming, Beck said.

Real effect
The findings match forecasts for Arctic greening predicted by various other methods, and they foreshadow effects that will strike closer to home later, Forbes said.

"What's happening now in the Arctic is a faster version of what will be happening at lower latitudes," Forbes told LiveScience.

That could worsen extreme weather events like Hurricane Sandy in the future.

"The snowstorms in Washington, D.C., and New York, and the flooding and the freezing on the River Thames — the extreme weather will continue to be extreme but it won't be so uncommon," Forbes said.

Follow Tia Ghose on Twitter @tiaghose. Follow LiveScience @livescience, Facebook and Google+. Original article on LiveScience.com.

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Beluga Shipping / AP

In this 2009 photo, a pair of German merchant ships traverse the fabled Northeast Passage through the Arctic.

Most of the sea ice that forms each fall and winter in the Arctic now melts each spring and summer, a recent change that is impacting global patterns of weather and trade as well as the U.S. military's strategic planning, experts told reporters during a briefing Tuesday.

"There are tremendous two-way and multiple interactions between the Arctic and the rest of the world," retired Rear Adm. David Titley said during the teleconference organized by Climate Nexus, a group trying to raise awareness about climate change.

Experts tied the melting ice in the Arctic to the recent spate of stormy winter weather in parts of the U.S. and Europe. They also noted that the prospect of ice-free summers in the Arctic as soon as 2030 is already impacting international trade and U.S. Navy plans to protect Arctic resources.

Maximum extent reached
The briefing was held the day after the National Snow and Ice Data Center (NSIDC) announced that the Arctic sea ice reached its maximum reach for the year on March 15, covering 5.84 million square miles. This is the sixth lowest maximum sea ice coverage in the 35-year satellite record.

"The last 10 years have been the lowest 10 years," said Walt Meier, a research scientist at the NSIDC. He added that while this year was low, "we actually have the largest growth of ice in our record from the minimum to the maximum" primarily because the ice was recovering from the record low in 2012. 

In addition to the shrinking extent of sea ice, the remaining ice is thinning perhaps twice as fast as the observed ice extent, noted Wieslaw Maslowski, an oceanographer at the U.S. Naval Postgraduate School.

Changing weather patterns
The changing sea ice dynamics are perhaps most felt outside of the Arctic via changes in weather patterns, noted Stephen Vavrus, a senior scientist with the National Institute Center for Climatic Research at the University of Wisconsin-Madison.

Slideshow: Snow blankets Midwest, heads east

Jim Vaiknoras / AP

A storm system stretching from the Dakotas to the Florida Panhandle is predicted to bring snow to the mid-Atlantic states.

Launch slideshow

The melting ice, he explained, allows heat stored in the ocean to escape to the atmosphere where it changes the pressure patterns, including "the jetstream level winds that affect our weather in the middle latitudes."

In particular, he and colleagues hypothesize that the warming Arctic causes the jetsteam to slow down and meander like a river flowing through the plains. This, in turn, transports less warm air over the lands from the oceans.

"That essentially helps to refrigerate the land during the wintertime and we get more cold and more snow and more extreme cold as well," Vavrus said. "And we've seen examples of that in this past winter with the slowed westerly wind."

The same meandering jetstream, he noted, could also explain the unusually warm spring in 2012. If a meandering jetstream is like a river, some bends are favorable to cold outbreaks, others are favorable to extreme warmth.

"Just depending on how those jetstream waves happen to set up in a particular week or month or season, that could help to explain why you could get weather extremes of both types," he said.

More commerce, new conflicts?
Less ice in the Arctic and the potential for ice-free summers is ratcheting up commercial interest in the region for oil and mineral extraction as well as use as a shipping route, developments that have the U.S. Navy studying how to establish an increased presence there.

"We see the potential for direct armed conflict in the Arctic to be very, very low," Titley said, but the military nevertheless is preparing its ships to be Arctic worthy, to establish infrastructure such as ports, and to strengthen communications and weather forecasting.

"The Arctic it is a very austere and harsh place," he said. "Even as it warms, it's a really hard place to operate." 

John Roach is a contributing writer for NBC News. To learn more about him, visit his website. 

NASA/Goddard

Maps of ozone concentrations over the Arctic on March 19, 2010 (left) and the same day in 2011 (right), measured by the Ozone Monitoring Instrument on NASA's Aura satellite.

By Stephanie Pappas, LiveScience

Cold temperatures, chlorine and a stagnant atmosphere caused a thinning in the ozone layer over the Arctic in 2011, a new NASA study finds.

This ozone loss is not the more famous ozone hole, found seasonally over Antarctica, which has been shrinking since the phase-out of chlorofluorocarbons, or CFCs, that interact with ozone molecules in the atmosphere. These ozone molecules are made of three oxygen atoms bound together. Their high concentration in the stratosphere about 12 miles to 19 miles above the Earth's surface blocks harmful ultraviolet light from the sun.

Arctic ozone depletion is typically not as severe as that in the Antarctic. Over the South Pole, the sun barely or never sets around Christmas, creating a confluence of sunlight and cold in the atmosphere. Under these conditions, chlorine from CFCs eats away at ozone molecules. [See Ozone Animation]

Arctic ozone
Up north, however, the sun reappears in the sky in the spring as temperatures start to warm, so the conditions aren't as favorable for ozone depletion. But in 2011, the ozone concentration in the late winter Arctic was about 20 percent lower than average. [North vs. South Pole: 10 Wild Differences]

"You can safely say that 2011 was very atypical: In over 30 years of satellite records, we hadn't seen any time where it was this cold for this long," study researcher Susan Strahan, an atmospheric scientist at NASA Goddard Space Flight Center, said in a statement.

Using atmospheric simulations, Strahan and her colleagues found that a mix of cold temperatures, chlorine and an unusually strong Arctic vortex caused the odd thinning. The Arctic vortex is a region of fast-blowing circular winds that get stronger each fall, creating an eddy of chilled air around the pole.

In 2011, the atmosphere was unusually quiet, allowing the Arctic vortex to remain strong well into the spring, after it usually breaks up. The reappearance of the sun in March while it was still especially cold created the conditions that led to the ozone thinning, the researchers report in the Journal of Geophysical Research - Atmospheres.

"Arctic ozone levels were possibly the lowest ever recorded, but they were still significantly higher than the Antarctic's," Strahan said. "There was about half as much ozone loss as in the Antarctic," and the levels remained above the threshold for calling the ozone loss an actual "hole," Strahan added. 

Future outlook
Strahan and her team calculate that two-thirds of the thinning was caused by a combination of chlorine pollution and extreme cold. The remaining third was caused by the oddly quiet atmosphere, which prevented ozone molecules from elsewhere from moving in to fill the gap.

The ozone layer over the Arctic returned to normal in April 2011. It's unlikely that such thinning will become a reoccurring problem, because the meteorological conditions were so odd, Strahan said. Not only that, but CFC levels in the atmosphere are still declining.

"If 30 years from now we had the same meteorological conditions again, there would actually be less chlorine in the atmosphere, so the ozone depletion probably wouldn't be as severe," she said.

Follow Stephanie Pappas @sipappas. Follow LiveScience on Twitter @livescience, Facebook or Google+. Original article on LiveScience.com.

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NASA's Goddard Space Flight Center Scientific Visualization Studio

Of the 10 million square miles (26 million square kilometers) of northern vegetated lands, 34 to 41 percent showed increases in plant growth (green and blue), 3 to 5 percent decreases in plant growth (orange and red), and 51 to 62 percent no changes (yellow) over the past 30 years, new research shows.

By LiveScience

Higher temperatures and a longer growing season mean some of Earth's chilliest regions are looking increasingly green, researchers say.

Today, the plant life at northern latitudes often looks like the vegetation researchers would have observed up to 430 miles (700 kilometers) farther south in 1982, according to a new study.

"It's like Winnipeg, Manitoba, moving to Minneapolis-Saint Paul in only 30 years," study researcher Compton Tucker of NASA's Goddard Space Flight Center in Greenbelt, Md., said in a statement.

Tucker and a team of university and NASA scientists looked at 30 years' worth of satellite and land surface data on vegetation growth from 45 degrees north latitude to the Arctic Ocean. In this region, large patches of lush vegetation now stretch over an area about the size of the continental United States and resemble what was found 4 to 6 latitude degrees to the south in 1982, the researchers say.

"Higher northern latitudes are getting warmer, Arctic sea ice and the duration of snow cover are diminishing, the growing season is getting longer and plants are growing more," climate scientist Ranga Myneni of Boston University said in a statement, adding that the changes are leading to great disruptions for the region's ecosystems. [10 Facts About Arctic Sea Ice]

The Arctic has been warming at a faster rate than the rest of the world in the past several decades, and Myneni says an amplified greenhouse effect is largely to blame for the changes in plant life. In this cycle, high concentrations of heat-trapping gasses drive up temperatures in the ocean and atmosphere. This warming cuts down Arctic sea ice and snow cover, causing the oceans and land surfaces in the region to be exposed (ice and snow are more reflective than darker surfaces); these surfaces absorb more heat from the sun's rays, which leads to further heating of the air and further reduction of sea ice and snow. Myneni warns that the cycle could get worse.

"The greenhouse effect could be further amplified in the future as soils in the north thaw, releasing potentially significant amounts of carbon dioxide and methane," Myneni said.

Using climate models, the team found that Arctic and boreal regions could see the equivalent of a 20-degree latitude shift by the end of this century due to rising temperatures. But this doesn't necessarily mean more and more plants. The researchers say the amplified greenhouse effect could have other consequences, like more forest fires, pest infestations and droughts, which cut vegetation growth.

And the availability of water and sunlight determines where plants will thrive. "Satellite data identify areas in the boreal zone that are warmer and dryer and other areas that are warmer and wetter," Ramakrishna Nemani of NASA's Ames Research Center in Moffett Field, Calif., explained in a statement. "Only the warmer and wetter areas support more growth."

The researchers also saw more plant growth in the boreal zone from 1982 to 1992 than from 1992 to 2011 — a trend they attributed to a lack of water in the region during the last two decades of the study.

The research was detailed Sunday in the journal Nature Climate Change.

Follow LiveScience on Twitter @livescience. We're also on Facebook and Google+.

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Julius Csotonyi

The giant ancestor of the modern camel lived in Arctic forests.

The ancestors of the modern camel included an Arctic giant that lived in chilly coniferous forests about 3.5 million years ago. The ancient ungulates were 30 percent bigger than living camels today, weighing about a ton.

Scientists pieced together a picture of this camel from a crop of 30 fossilized bone fragments found on Ellesmere Island in the Canadian Arctic. It's the first evidence that camel ancestors lived so far north. The location and age of the bone fragments indicate that the camel lived at time when the planet was 5.4 degrees Fahrenheit (3 degrees Celsius) warmer than it is today, when parts of the Arctic were covered in coniferous forests filled with larch and birch. The Ellesmere Island region itself was about 36 degrees F (20 degrees C) warmer than it is today.

"Being big was something camels did very well," Natalia Rybczynski, a research scientist at the Canadian Museum of Nature told NBC News. "An animal today that would be an analogue is the moose — it's huge," she added. A large body size would have allowed it to regulate its body temperature better during the winters and cover larger distances walking, she explained. Rybczynski and her collaborators described the fossil and its analysis in a paper published Tuesday in Nature Communications.

Today's living camels have broad, flat feet, to help them walk on sand. Those feet could have evolved in an Arctic camel to walk on snow, Rybczynski says. And the ability to pack away fat, as the modern camel does in its hump, could have been useful to an Arctic camel that needed to survive dark, snowy winters that were six months long. 

Martin Lipman/Canadian Museum of Nature

These 30 fossil bone fragments belong to the tibia of a 3.5 million year-old camel ancestor.

Martin Lipman/Canadian Museum of Nature

This fossil chunk of the camel looks similar to wood. "You pick up everything that might be a fossil," Natalia Rybczynski says. When the day's find is analyzed back at camp, there are sometimes pleasant surprises. "We get back and say, 'Oh, it's not a piece of wood, it's a bone!'"

Rybczynski found the first fragment of the specimen in 2006. Over later visits in 2006, 2008 and 2010, she and her collaborators assembled a collection of 30 bone fragments that fit together to resemble the tibia of a large ungulate. A closer analysis of the structure of the bone hinted that they had a large cud chewer on their hands. 

For further proof, the team extracted collagen, a protein, from the fossils. Frozen in the Arctic mud, the biological molecule was preserved exceptionally well, and it survived better than ancient DNA would have fared. "It's mummified," Rybczynski said. Collagen isn't as information-rich as DNA, but has enough of a chemical fingerprint to show which family of animals the fragments came from. The ancient northern camel is related to today's dromedary, and to another now-extinct camel relative called the Yukon camel.

The high Arctic camel's fossil traces suggest that weird adaptations found in the modern camel may have arisen to fill a different need in its ancestors, and serve as a historical example of a species that lived on a planet that was warmer than it is today. That's what makes the fossil hunt fun fo Rybczynski. "You can pick up these tiny fragments that are that big, that makes these connections," she says. 

Nidhi Subbaraman writes about science and technology. Follow on Google+, Twitter, Facebook. 

Seymour Laxon / University College London

This is an Arctic sea ice ridge at one of the sites used to validate ice thickness measurements from the CroySat-2.

Thick sea ice is disappearing from a broad swath of the Arctic, according to new satellite data that confirms estimates from computer models and suggests the region may be ice free during the summers sooner rather than later.

The Arctic sea ice reached a new record minimum extent in 2012, when it covered nearly half the average area it did from 1979 to 2010. The new data show the Arctic sea ice volume in the fall, when it is at its lowest, has declined more than a third between 2003 and 2012. Ice volume in the winter has declined 9 percent.

"Not only is the area getting smaller, but also its thickness is decreasing and making the ice more vulnerable to more rapid declines in the future," Christian Haas, a geophysicist at York University in Canada, told NBC News.

Sea ice extent can change in response to melting from warmer ocean and air temperatures as well as getting shifted around by winds and currents, which can push it into thick piles.

"The latter process would not change the volume of the ice," explained Haas. "But now we know that not only the area decreases, but also the thickness and therefore the total volume decreases."

The new observations are the first data analyzed from the European Space Agency’s CryoSat-2 satellite, which was launched in 2010. It uses a technique called radar altimetry to measure the thickness of the sea ice, which reveals the volume of the ice there, not just how much of the Arctic it covers.

A NASA satellite collected similar data between 2003 and 2008 and helped researchers verify a computer model used to compute ice volume based on weather records, sea-surface temperature and satellite imagery. 

Axel Schweiger / UW

Monthly sea ice volume anomalies from 1979 to the present calculated using the PIOMAS system.

In recent years, that model, called the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS), has generated some controversy because of the substantial ice loss it showed, according to the University of Washington, where it was built.

"These (new) data essentially confirm that in the last few years, for which we haven’t really had data, the observations are very close to what we see in the model," Axel Schweiger, a polar scientist with the university’s Applied Physics Laboratory, said in a news release. 

"So that increases our confidence for the overall time series from 1979 to present."

In a follow-up telephone interview with NBC News, Schweiger added that for the eight-year satellite record, the estimates from PIOMAS have actually been less than what was observed.

"We knew that our system was conservative, we had a sense of that," he said, "but this confirms it."

Going forward, researchers will use the PIOMAS to forecast when the Arctic will be ice free in the summers, a phenomenon that may impact everything from global shipping to weather patterns. Some studies indicate that could come as early as 2040. 

"As the satellite measurements show that not only the area decreases but also its thickness, it is actually becoming more likely that the ice will disappear sooner rather than later," Haas told NBC News.

John Roach is a contributing writer to NBC News. To learn more about him, check out his website. 

NASA / Goddard / MODIS Rapid Response Team

This mosaic of images taken by NASA's Aqua satellite shows an unusually strong storm over the Arctic Ocean on Aug. 6, 2012.

By Becky Oskin
Our Amazing Planet

The scene of the crime: The Arctic.

The suspect: The Great Arctic Cyclone of August 2012.

The victim: The Arctic sea ice, which melted to a record low area last year.

"The Great Arctic Cyclone of August 2012" arose in Siberia on Aug. 2 and crossed the Arctic Ocean to Canada, lasting an unusually long 13 days. The cyclone hit a pressure minimum of 966 millibars on Aug. 6, the lowest ever recorded for an Arctic storm. The stronger the pressure gradient, or difference in pressure, the stronger the winds associated with a storm.

Since the storm, which was equal in strength to a hurricane, tore across the Arctic, scientists have wondered whether its winds and waves were a guilty party in the disappearing Arctic sea ice.

Guilty or not guilty?
To solve the mystery, climate scientists from the University of Washington performed the equivalent of a forensic exam: They ran a computer simulation of last summer's weather and compared it against a second scenario that was identical, except that there was no cyclone.

"The storm was enormous," study co-author Axel Schweiger, a polar scientist in the university's Applied Physics Laboratory, said in a statement. "The impact on the ice was immediately obvious, but the question was whether the ice that went away during the storm would have melted anyway because it was thin to begin with."

Though the storm had a huge impact on sea ice while it passed, within two weeks, the effect diminished, lead author Jinlun Zhang, also a scientist in the university's Applied Physics Laboratory, said in the statement.

The final verdict? Not guilty

The scientists conclude the cyclone reduced the final September ice extent by almost 60,000 square miles (150,000 square kilometers), an additional 5 percent. However, they point out that 2012's record loss was 18 percent greater than the previous low, set in 2007. [ Video: Powerful Arctic Cyclone Wreaks Havoc on Sea Ice ]

"Thus without the storm, 2012 would still have produced a record minimum," the authors report in their study, which appears online this week in the journal Geophysical Research Letters.

Warmed from below
The research also revealed an unusual mechanism for the cyclone-related melting. A study published on Dec. 15, 2012, in the same journal focused on winds breaking up the ice or driving ice floes into areas of warmer water.

But the University of Washington team found that during the storm, the ice melted largely from warm ocean water churned up by the passing storm. Melting quadrupled during the storm, and the rate of ice loss doubled, the study found.

In the Arctic summer, ocean water becomes stratified from melting ice, according to a statement from the university. A layer of ice-cold fresh water sits just beneath the sea ice. But about 65 feet (20 meters) below the surface, there is a layer of denser, saltier water that has been gradually warmed by the sun's rays.

When the cyclone swept over the drifting ice floes, underside ridges churned up the water, bringing sun-warmed seawater to the ice's bottom edge and causing it to melt, the study suggests.

Reach Becky Oskin at boskin@techmedianetwork.com. Follow her on Twitter @beckyoskin. Follow OurAmazingPlanet on Twitter @OAPlanet. We're also on Facebook   and   Google+.

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