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CU researchers say deep ice cores show past Greenland warm period may be ‘road map’ for continued warming of planet
Jan 23rd
A new study by an international team of scientists analyzing ice cores from the Greenland ice sheet going back in time more than 100,000 years indicates the last interglacial period may be a good analog for where the planet is headed in terms of increasing greenhouse gases and rising temperatures.
The new results from the NEEM deep ice core drilling project led by the University of Copenhagen and involving the University of Colorado Boulder show that between 130,000 and 115,000 years ago during the Eemian interglacial period, the climate in north Greenland rose to about 14 degrees Fahrenheit warmer than today. Despite the strong warming signal during the Eemian — a period when the seas were roughly 15 to 25 feet higher than today — the surface of the north Greenland ice sheet near the NEEM facility was only a few hundred yards lower than it is today, an indication to scientists it contributed less than half of the total sea rise at the time.
The NEEM project involves 300 scientists and students from 14 countries and is led by Professor Dorthe Dahl-Jensen, director of the University of Copenhagen’s Centre of Ice and Climate. CU-Boulder geological sciences professor and ice core expert Jim White is the lead U.S. investigator on the project. The National Science Foundation’s Division of Polar Programs funded the U.S. portion of the effort.
The new Nature findings showed that about 128,000 years ago, the surface elevation of ice near the NEEM site was more than 650 feet higher than present but the ice was starting to thin by about 2 inches per year. Between about 122,000 and 115,000 years ago, Greenland’s surface elevation remained stable at roughly 425 feet below the present level. Calculations indicate Greenland’s ice sheet volume was reduced by no more than 25 percent between 128,000 years ago and 122,000 years ago, said White.
A paper on the subject was published in the Jan. 24 issue of Nature.
“When we calculated how much ice melt from Greenland was contributing to global sea rise in the Eemian, we knew a large part of the sea rise back then must have come from Antarctica,” said White, director of CU-Boulder’s Institute of Arctic and Alpine Research. “A lot of us had been leaning in that direction for some time, but we now have evidence that confirms that the West Antarctic ice sheet was a dynamic and crucial player in global sea rise during the last interglacial period.”
Dahl-Jensen said the loss of ice mass on the Greenland ice sheet in the early part of the Eemian was likely similar to changes seen there by climate scientists in the past 10 years. Other studies have shown the temperatures above Greenland have been rising five times faster than the average global temperatures in recent years, and that Greenland has been losing more than 200 million tons of ice annually since 2003. The Greenland ice loss study was led by former CU-Boulder scientist Isabella Velicogna, who is currently a faculty member at the University of California, Irvine.
The intense melt in the vicinity of NEEM during the warm Eemian period was seen in the ice cores as layers of re-frozen meltwater. Such melt events during the last glacial period were rare by comparison, showing that the surface temperatures at the NEEM site were in a cold, nearly constant state back then. But on July 12, 2012, satellite images from NASA indicated 97 percent of Greenland’s ice sheet surface had thawed as a result of warming temperatures.
“We were quite shocked by the warm surface temperatures observed at the NEEM ice camp in July 2012,” said Dahl-Jensen. “It was raining at the top of the Greenland ice sheet, and just as during the Eemian period, meltwater formed subsurface ice layers. While this was an extreme event, the present warming over Greenland makes surface melt more likely, and the predicted warming over Greenland in the next 50-100 years will very likely be so strong that we will potentially have Eemian-like climate conditions.”
The Greenland ice core layers — formed over millennia by compressed snow — are being studied in detail using a suite of measurements, including stable water isotope analysis that reveals information about temperature and greenhouse gas levels and moisture changes back in time. Lasers are used to measure the water stable isotopes and atmospheric gas bubbles trapped in the ice cores to better understand past variations in climate on an annual basis — similar in some ways to a tree-ring record.
The results from the Nature study provide scientists with a “road map” of sorts to show where a warming Earth is headed in the future, said White. Of the nine hottest years on Earth on record, eight have come since the year 2000. In 2007 the Intergovernmental Panel on Climate Change concluded that temperatures on Earth could climb by as much as 11 degrees F by 2100.
Increasing amounts of carbon dioxide in the atmosphere from sources like vehicle exhaust and industrial pollution — which have risen from about 280 parts per million at the onset of the Industrial Revolution to 391 parts per million today — are helping to raise temperatures on Earth, with no end in sight, said White.
“Unfortunately, we have reached a point where there is so much carbon dioxide in the atmosphere it’s going to be difficult for us to further limit our impact on the planet,” White said. “Our kids and grandkids are definitely going to look back and shake their heads at the inaction of this country’s generation. We are burning the lion’s share of oil and natural gas to benefit our lifestyle, and punting the responsibility for it.”
In the past, Earth’s journey into and out of glacial periods is thought to be due in large part to variations in its orbit, tilt and rotation that change the amount of solar energy delivered to the planet, he said. But the anthropogenic warming on Earth today could override such episodic changes, perhaps even staving off an ice age, White said.
While three previous ice cores drilled in Greenland in the last 20 years recovered ice from the Eemian, the deepest layers were compressed and folded, making the data difficult to interpret. Although there was some folding of the lowest ice layers in the NEEM core, sophisticated ice-penetrating radar helped scientists sort out and interpret the individual layers to paint an accurate picture of the warming of Earth’s Northern Hemisphere as it emerged from the previous ice age, White said.
In addition to White, other CU-Boulder co-authors on the NEEM paper include INSTAAR scientist Bruce Vaughn and graduate student Tyler Jones of INSTAAR and CU-Boulder’s Environmental Studies Program.
“It’s a challenge being on the ice sheet, because we are out of our comfort zones and are working long, physical hours in an environment that is extremely cold and where the sun never sets,” Jones said. “Being a member of the research team allowed me to understand the ice core recovery process and the science behind it in terms of learning more about past climates and the implications for future climate change.”
Other nations involved in NEEM include Belgium, Canada, France, Germany, Iceland, Japan, Korea, the Netherlands, Sweden, Switzerland and the United Kingdom. Other U.S. institutions involved in the effort include Oregon State University, Penn State, the University of California, San Diego and Dartmouth College.
For more information on INSTAAR go to http://instaar.colorado.edu/. Additional information, photos and videos on NEEM can be found at http://www.neem.ku.dk.
A video and a slide show on the project will be available on the CU-Boulder news site by clicking on the story headline at http://www.colorado.edu/news.
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Huskies Put The Bite On Frigid Buffs
Jan 17th
SEATTLE – The Colorado Buffaloes dug themselves a hole with frigid shooting here Wednesday night and left Alaska Airlines Arena in a deeper Pac-12 Conference hole.
But despite their 64-54 loss to streaking Washington, which won for the tenth time in 12 games, Buffs coach Tad Boyle and his players believe positive steps were taken – particularly on defense. Boyle said his team’s defense “was good enough to win . . . our guys played great (defense). We played with pride and some toughness. We lost to a good basketball team.”
The Huskies, playing their first home game since Dec. 22, remained unbeaten (4-0) in conference play and went to 12-5 overall while the Buffs slipped to 1-4, 11-6. If CU’s ‘D’ was exemplary, its ‘O’ was of the OMG variety. Credit the Huskies for some of that misfiring; they’ve now held four Pac-12 teams to under 40 percent from the field.
The Buffs shot a season-low 29.2 percent in the first half and finished at 36.2 percent (21-for-58) for the game – the team’s second-lowest mark this season. CU also tied a season low in assists with six and made only one of 10 three-point attempts. But the Buffs held the Huskies to 33.9 percent (20-for-59) from the field and outrebounded them by one (38-37). It wasn’t an aesthetically pleasing game for either team, but UW coach Lorenzo Romar didn’t care.
Asked about “winning ugly,” Romar said, “You can color it any want to color it. I just know that when you go out and you play two games in a row and you have single digit turnovers (UW had 9, CU 12), you hold four teams to under 40 percent from the field, you outrebound three out of the four, you’re beginning to do things right. The only ‘ugly’ thing, if you want to call it that, is that we haven’t been making shots. Two out of the last four games we haven’t made shots. Other than that, I think we’re doing everything else OK.”
Boyle said the Huskies’ 15 offensive rebounds “really killed us in the second half. We had some stops and couldn’t finish the possession with getting the rebound. That hurt us. And then we put them on the foul line in the second half. For some reason we don’t get to the foul line on the road; I don’t know why.”
Sophomore Spencer Dinwiddie, who led CU with 15 points, said the Buffs played with more overall intensity than in previous conference losses to Arizona, Arizona State and UCLA.
“For sure,” Dinwiddie said. “That’s one thing we talked about. We talked our positives; we finally started playing with our principles – we rebounded the ball decently. There were a couple of possessions where they got three or four offensive rebounds. If we cut that out and they don’t make a run, the game’s different.”
The only other CU player in double figures was junior Andre Roberson with 10 points, marking the first time this season only two Buffs reached double digits. Roberson also had 11 rebounds for his seventh double-double of the season and the 32nd of his career.
Roberson said the Buffs “stepped it up big time on the defensive end . . . we just didn’t get the rebounds when it mattered and we didn’t make the tough stops. Our offense has to get better; our motion is terrible right now. That’s one thing we have to improve on big time. Just executing on the offense end is a main thing. That’s why we struggled with this team.”
Sophomore guard Askia Booker fouled out with 34.4 seconds to play after scoring nine points, while freshman forwards Xavier Johnson and Josh Scott had nine and eight, respectively. Scott got all of his points in the second half.
The Huskies’ C.J. Wilcox, the conference’s leading scorer (21.3 ppg), finished with 25, while teammate Scott Suggs added 13. UW had no other double-figure scorers, but Desmond Simmons (12) and Aziz N’Diaye (11) accounted for 23 rebounds.
CU scored a season-low 20 points in the first half and trailed by eight at intermission. The Huskies opened 10-point leads three times in the game’s final 8 minutes, an 11-point advantage in the last 3 minutes, and never allowed their visitors closer than seven points during that span. Trailing 28-20 at intermission, the Buffs might have gone to their locker room thankful for that deficit. When they caught the Huskies at 17-17 on a layup by Johnson – he started against in place of Sabatino Chen – they appeared to have corrected their early problems.
CU committed four of its seven first-half turnovers – a high for a half in league play – in the game’s first 6 minutes and fell behind by seven points. Then the Buffs strung together an 8-2 run – their most productive offensive stretch of the opening half – and pulled even.
But things went south from there. After Johnson’s layup produced the tie at 17 with 8:56 left before the break, CU scored only three more points to finish with its lowest first-half total of the season.
The Buffs opened the second half with three points from Roberson and pulled to within 28-23. But the Huskies trumped that with a four-point play from Scott Suggs to take their largest lead of the night – 32-23 – to that point. The nine-point advantage became 10 (37-27) on a trey by Wilcox. But taking advantage of the 7-foot N’Diaye taking a rest, the 6-10 Scott hit back-to-back baskets to draw the Buffs to within five (39-34) with just over 11 minutes to play.
CU’s threat ended there. A 5-0 run restored U-Dub’s 10-point lead (48-38), leaving the Buffs just over 7 minutes to retaliate. Boyle called a timeout at the 7:12 mark, but the closest his team could get was 52-45 on a three-point play by Dinwiddie with 3:52 to play.
“With our defense tonight and our pride, I’m proud of our guys for the way they hung in there,” Boyle said. “It got away from us at the end there and you look at a 10-point loss on the road and we couldn’t shrink the lead because we couldn’t score. But it wasn’t because of our defense.”
The Buffs’ road trip continues with a Saturday game (8 p.m. MST) at Washington State. The team will fly via charter on Thursday morning from Seattle to Spokane, have Thursday and Friday practices at Gonzaga, then fly to Pullman on Saturday morning.
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Woodyard’s skills and dedication make him a team leader
Jan 10th
This season, he fought for a Pro Bowl berth as one of the AFC’s most productive linebackers. Through 15 games, Woodyard is one of just four AFC players with at least 100 tackles, a sack and an interception. He’s set career highs in almost every category this season, including his three interceptions and four sacks.
“I’m trying to continue to work on my craft and get better every day,” Woodyard said. “My teammates believe in me, and I’ve just been having fun out there this year. Not worrying about anything, just going out there and playing football.”
He’s already earned some hardware this season, taking home his first career AFC Defensive Player of the Week Award after becoming the first player in team history to post one sack, one interception and one forced fumble in the same game during Denver’s 34-14 win over the New Orleans Saints in Week 8.
As he’s gotten more time in the starting lineup, Woodyard’s confidence and comfort level have grown.
“Whenever we step on the field, we expect to win and we know we should win every game we play,” Woodyard said. “That confidence just seeps out of everybody’s pores in the game. You actually smell that confidence in the game. It’s not being overconfident, it’s just having fun and enjoying the game.”
While his season might have caught some people off guard, Woodyard’s teammates knew what he was capable if given an opportunity.
“It was only a matter of time,” cornerback and fellow team captain Champ Bailey said. “It’s all about opportunities. Most guys make the best of them and he’s one of them. I’m happy for him because I’ve seen how much he’s grinded away and worked up to this point.”
Linebacker Von Miller saw first-hand how hard Woodyard worked on the practice field and in their position’s meeting room.
“I’m not surprised at all,” Miller said. “Since I’ve been here, he’s been making big-time plays, doing big-time things, so for him to come out here and have the type of season that he’s having isn’t a surprise at all.”
UNDRAFTED UNDERDOG
In 2008, 253 players had their names called during the NFL draft, but Woodyard wasn’t one of them. Despite earning first-team All-SEC honors during his final two seasons at the University of Kentucky, where he led the conference with 10.6 tackles per game as a senior, Woodyard went undrafted.
He joined the Broncos as a free agent and immediately opened eyes with his work ethic and playmaking ability.
“I came in my rookie year and I just wanted to give them my all and have a shot to play the game that I love to play,” Woodyard said. “It was just exciting. It was a lot of hard work and determination. I just stuck by myself and believed in myself.”
He has played double-digit games in each of his five seasons, but still remembers where he started his career.
“I keep that chip on my shoulder,” Woodyard said. “I never take anything for granted. Always work hard and outwork whoever is out there beside you. It keeps me humble.”
After starting his rookie season as an undrafted free agent, he finished the year as a team captain. Woodyard has held that position ever since to become just the second Bronco in franchise history to serve as a captain in his first five seasons with the club, joining Hall-of-Fame running back Floyd Little with that distinction.
“I just lead by example,” Woodyard said. “I don’t like to talk a lot, I just like to go out there and do it the right way and do it the way I’ve been coached to do it. Do it the way my teammates depend on. That’s going out there and playing hard-nosed football until the end of the whistle every snap.”
Having climbed from the bottom of the depth chart to a starting role, Woodyard serves as a living example for the college free agents that join the team each summer fighting the odds for a spot on the roster.
“It gives me the opportunity to be on that same level and talk to them and tell them what they need to do and what they should do,” he said. “For the most part, they listen to me and they look up to me and they always seek out advice.”
In 2011, cornerback Chris Harris began the year as an undrafted free agent and has emerged as a starter this season.
Harris credits Woodyard’s leadership and example as a factor in his success.
“Just to always continue working,” Harris said about the advice he received from Woodyard. “Any time you see a guy go undrafted it definitely gives you a chance, knowing that you can come from the bottom and start in this league.”
COMMUNITY-DRIVEN CAPTAIN
Woodyard has taken that leadership beyond the playing field and into the community.
Named the Broncos’ recipient of the Walter Payton NFL Man of the Year in each of the previous two seasons, Woodyard said he enjoys using his position as a football player to help people.
“I think that’s what it starts with,” Woodyard said. “It’s important that we give back to the community and help out the community that we’re in. I think that’s what our world is missing. We don’t reach out and we don’t help enough people. That’s something with my status of being a football player in the NFL, I take advantage of every opportunity that I can to help out.”
Woodyard even set up his own foundation, 16Ways, which works with at-risk youth. As a team captain, Woodyard has tried to impress upon the younger players the importance of taking the time to be active in community enrichment programs.
“I love seeing guys sign up for them,” Woodyard said about the team’s community events. “I used to be the first one to sign up, now it’s funny, when I come around the corner, now there’s 10 guys that have already signed up for an event. That’s always good. Now there are more rookies at every event than I’ve ever seen.”
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