Climate News

December 16, 2010

Wind turbines in Midwestern farm fields may be doing more than churning out electricity. The giant turbine blades that generate renewable energy might also help corn and soybean crops stay cooler and drier, help them fend off fungal infestations and improve their ability to extract growth-enhancing carbon dioxide from the air and soil.

The preliminary findings of a months-long study that examines how wind turbines on farmlands interact with surrounding crops were presented today at the annual fall meeting of the American Geophysical Union in San Francisco. The presentation was made by researcher Gene Takle of the U.S. Department of Energy's Ames Laboratory and Julie Lundquist, assistant professor in the University of Colorado at Boulder's atmospheric and oceanic studies department.

"We've finished the first phase of our research, and we're confident that wind turbines do produce measureable effects on the microclimate near crops," said agricultural meteorology expert Takle, who also is the director of the Climate Science Program at Iowa State University.

According to Takle, turbine blades channel air downward, in effect bathing the crops below with the increased airflow they create.

"Our laser instrument could detect a beautiful plume of increased turbulence that persisted even a quarter-mile downwind of a turbine," said Lundquist, who also is a joint appointee at the U.S. Department of Energy's National Renewable Energy Laboratory, and a fellow of the Renewable and Sustainable Energy Institute, a joint institute of CU-Boulder and NREL.

Lundquist's team uses a specialized laser known as lidar to measure winds and turbulence from near the Earth's surface to well above the uppermost tip of a turbine blade.

Both Lundquist and Takle stressed their early findings have yet to definitively establish whether or not wind turbines are beneficial to the health and yield potential of soybeans and corn planted nearby. However, their finding that the turbines increase airflow over surrounding crops suggests this is a realistic possibility.

"Because wind turbines generate turbulence and the mixing of air downwind, they may accelerate the natural exchange processes between crops and the lower part of the atmosphere," said Lundquist.

For example, the sun warms crops and some of that heat is given off to the atmosphere. Extra air turbulence likely speeds up this heat exchange, so crops may stay slightly cooler on hot days, Lundquist said. On cold nights, the turbulence created by the wind turbines stirs the lower atmosphere and keeps nighttime temperatures around the crops warmer.

"In both the spring and in the fall, we suspect that turbines' effects are beneficial by warming and perhaps preventing a frost, thus extending the growing season," said Lundquist.

Wind turbines also may have positive effects on crop moisture levels. Extra turbulence may help dry the dew that settles on plants, minimizing the amount of time fungi and toxins can grow on plant leaves. Additionally, drier crops at harvest help farmers reduce the cost of artificially drying corn or soybeans.

Another potential benefit to crops is that increased airflows could enable corn and soybean plants to more readily extract CO2, a needed fuel for crops, from the atmosphere and the soil, thus helping the crops' ability to perform photosynthesis.

Takle's wind turbine predictions are based on years of research on so-called agricultural shelter belts, which are rows of trees in a field designed to slow high-speed natural winds.

"In a simplistic sense, a wind turbine is nothing more than a tall tree with a well-pruned stem," said Takle. "For a starting point for this research, we adapted a computational fluid model that we use to understand trees, but we plan to develop a new model specific to wind turbines as we gather more data."

The team's initial measurements consisted of visual observations of wind turbulence upwind and downwind of the turbines. The team also used wind-measuring instruments called anemometers to determine the intensity of the turbulence. The bulk of the wind-turbulence measurements and the crop-moisture, temperature and CO2 measurements took place in the spring and summer of this year.

"We anticipate the impact of wind turbines to be subtle, but in certain years and under certain circumstances the effects could be significant," said Takle. "When you think about a summer with a string of 105-degree days, extra wind turbulence from wind turbines might be helpful. If turbines can bring the temperature down below 100 degrees that could be a big help for crops."

The CU-Boulder and ISU teams hope to continue their measurements throughout the next growing season.

"These data are quite encouraging, and we look forward to collecting more data to ensure the certainty of these results," said Lundquist. "As wind energy expands in future years to provide a domestic source of energy, we'll need robust measurements to understand and predict the impacts of that expansion."

The research was funded or supported by Ames Laboratory, the Department of Energy's Office of Energy Efficiency and Renewable Energy, the U.S. National Laboratory for Agriculture and the Environment, CU-Boulder and NREL.

To view a video of Takle discussing the study of wind turbines on farmland visit www.youtube.com/watch?v=r7qNNvYVKI4&feature=player_embedded

Contact
Julie Lundquist, 303-492-8932
julie.lundquist@colorado.edu

Elizabeth Lock, 303-492-3117
elizabeth.lock@colorado.edu

December 15, 2010

Rising concentrations of zinc in a waterway on Colorado's Western Slope may be the result of climate change that is affecting the timing of annual snowmelt, says a new study led by the University of Colorado at Boulder.

The study focused on the Snake River watershed just west of the Continental Divide near Keystone, Colo., where CU-Boulder researchers have observed a four-fold increase in dissolved zinc over the last 30 years during the lowest water flow months, said Caitlin Crouch. Crouch, a master's degree student who led the study, said the high levels of zinc affect stream ecology, including deleterious effects on microbes, algae, invertebrates and fish.

The team speculated the increased zinc concentrations may be tied to changes in groundwater conditions and stream flow patterns caused by climate change and the associated snowmelt that has been peaking two to three weeks earlier than normal in recent years, largely because of warming air temperatures. The result is lowered stream flows and drier soils along the stream in September and October, which increases metal concentrations, said Crouch.

"While most of the talk about climate change in western waterways is about decreasing water quantities, we are evaluating potential climate influences on water quality, which is a whole different ball game," she said.

Crouch gave a presentation on the subject at the fall meeting of the American Geophysical Union held in San Francisco Dec. 13-17. The study was co-authored by Professor Diane McKnight of CU-Boulder's civil and environmental engineering department.

The zinc in the Snake River watershed is primarily a result of acid rock drainage, or ARD, which can come from abandoned mine sites along rivers or through the natural weathering of pyrite in the local rock, said Crouch. Sometimes enhanced by mining activity, weathering pyrite forms sulfuric acid through a series of chemical reactions, which dissolves metals like zinc and carries them into the groundwater.

McKnight, also a fellow of CU-Boulder's Institute of Arctic and Alpine Research, said there are nearly 2,000 miles of waterways in Colorado affected by ARD.

One of the most noticeable impacts of ARD in the Upper Snake River drainage is on the fishery downstream, said Crouch, a graduate student in CU-Boulder's Environmental Studies Program. Rainbow trout populations in much of the river are not self-sustaining because of ecologically harsh stream conditions, and the waterway requires stocking several times a year.

The elevated zinc in the Snake River comes from several ARD sources, said Crouch. Crouch's study site -- where an increasing trend in zinc concentrations is sustained by groundwater discharge -- is above the Peru Creek tributary to the Snake River, where natural pyrite weathering is thought to be the main source of ARD. Peru Creek is largely devoid of life due to ARD from the abandoned Pennsylvania Mine and other smaller mines upstream and has been a target for potential remediation efforts.

McKnight said another factor involved in rising zinc levels in the Snake River watershed -- which runs from the top of the Continental Divide to Dillon Reservoir -- could be the result of the severe 2002 drought in Colorado. The drought significantly lowered waterways, allowing more pyrite to be weathered in dry soils of the watershed and in wetlands adjacent to the stream.

As part of her study, Crouch measured zinc concentrations in an alpine tributary of the Upper Snake River. She found that zinc concentrations there were 10 times higher than in the main stem of the waterway and correlated with increased sulfate, so-called "hard water" containing calcium and magnesium, and a variety of metals.

"This supports our contention that the increasing zinc concentrations we are seeing in the watershed are driven by the acceleration of ARD," Crouch said. "One of the things I still am trying to parse out is whether metals like zinc are coming from one discrete source or are being diffused into the watershed from the groundwater beneath."

Cleaning up abandoned, polluted mines like the Pennsylvania Mine remains a problem largely because of liability issues since the mine owners who normally would be responsible for the mine cleanup are long gone. The Environmental Protection Agency has begun an agency-wide effort to reduce barriers to the cleanup of abandoned mine sites by local environmental groups and volunteers.

In the case of the Pennsylvania Mine, the Snake River Task Force is working with partners like the Keystone Ski Resort, the Keystone Center, Trout Unlimited, the Northwest Colorado Council of Governments, Summit County, the Colorado Department of Public Health and Environment, the EPA and the Blue River Watershed Group.

Seven CU-Boulder graduate students have produced master's and doctoral theses under McKnight on environmental issues related to the Snake River watershed. Copies of the studies have been provided to the Snake River Task Force to help assess the current and future stream chemistry and biology in the area.

Contact

Caitlin Crouch, 619-987-4030
Caitlin.Crouch@colorado.edu
Diane McKnight, 303-492-4687
Diane.McKnight@colorado.edu
Jim Scott, 303-492-3114
Jim.Scott@colorado.edu

December 14, 2010

A novel project using cameras mounted on unmanned aircraft flying over the Arctic is serving double duty by assessing the characteristics of declining sea ice and using the same aerial photos to pinpoint seals that have hauled up on ice floes.

The project is the first to use aircraft to monitor ice and seals in remote areas without putting pilots and observers at risk, said Elizabeth Weatherhead of the University of Colorado at Boulder, who is leading the study team. Weatherhead is a senior scientist at the Cooperative Institute for Research in Environmental Sciences, a joint venture of CU-Boulder and the National Oceanic and Atmospheric Administration.

Monitoring the seals is important because the Arctic is rapidly warming as a result of human-produced greenhouse gases building up in Earth's atmosphere, according to climate scientists. Warming temperatures and sea ice loss are of concern to biologists because they are impacting at least some Arctic marine and terrestrial mammals.

"Because ice is diminishing more rapidly in some areas than others, we are trying to focus on what areas and types of ice the seals need for their survival," said Peter Boveng, leader of the Polar Ecosystems Program at NOAA's Alaska Fisheries Science Center.

"By finding the types of ice they prefer, we can keep track of that ice and see how it holds up as the Arctic sea ice extent shrinks," said Weatherhead.

Weatherhead gave a presentation on the subject at the fall meeting of the American Geophysical Union held in San Francisco Dec. 13 to Dec. 17. Other scientists involved in the project include Boveng, Robyn Angliss, deputy director of NOAA's National Marine Mammal Laboratory in Seattle, NMML researchers Michael Cameron and Erin Moreland, and the University of Alaska Fairbanks' Greg Walker.

The four species of Arctic seals of most interest to the research team are the bearded, ringed, spotted and ribbon seals, each of which rely in some way on sea ice for breeding, resting and as a safe haven from predators.

Known as the "Scan Eagle," the unmanned aircraft was launched in May and June of 2009 from the NOAA vessel McArthur II over the Bering Sea west of Alaska. The drone has a 10-foot wingspan and is owned and operated by the University of Alaska.

The image recognition software was developed by Boulder Labs Inc. in Boulder, Colo., and used to automate the identification of seals in 27,000 images that were collected during the flights. "The results show that the seals have distinct preferences for specific types of ice, demonstrating that ice extent is not the only factor affecting seal populations," said Weatherhead.

The Scan Eagle flights lasted from two to eight hours and flew at altitudes ranging from 300 to 1,000 feet. While the amount of ocean and ice scanned by the unmanned aircraft was small -- it flew 3- to 5-mile-long transects over the Bering Sea -- the researchers were eager to see whether the image recognition system would work for characterizing both the ice and the seals. "The answer was a resounding yes," Weatherhead said.

The analysis of sea ice by the team included edge-to-area calculations of ice floes as well as ice floe size and distribution. "There is an incredible variety of ice and we are trying to come up with mathematical ways to describe it," she said. "One thing that really interests us is how broken up the ice is in particular areas."

According to CU-Boulder's National Snow and Ice Data Center, the total loss of Arctic sea ice extent from 1979 to 2009 was an area larger than the state of Alaska. Scientists there believe the Arctic may become ice-free during the summers within the next several decades.

In December 2010, NOAA's Fisheries Service proposed to list the Arctic ringed seal as threatened under the Endangered Species Act because of diminishing sea ice and snow cover. Arctic ringed seals do not come ashore, but use sea ice for whelping, nursing and resting. Ringed seal pups are born in snow caves on the ice, and their survival can be affected by snow depths and the timing of spring snowmelt and ice breakup.

"Biologists are thrilled about the image recognition software because it could change the way we monitor seal populations," said Weatherhead. "We can send an unmanned craft out from a ship, collect 4,000 images, and have them analyzed before dinner. This is a great example of physicists working closely with biologists who are concerned with the health of seal populations."

Typically, seals appear in less than 1 percent of the images, said Weatherhead. But on the ice floes or ice edges where they are found, the software can help researchers identify seals by species. In the future, researchers might be able to identify the relative age and gender for some seal species. The software could even be adjusted to look for polar bears and their tracks.

Weatherhead said the team wants to combine its results with forecasts not only of future sea ice extents, but also of future ice characteristics that will allow for predictions regarding the impacts of changing and disappearing ice types on seal populations.

CIRES has even turned the project into a middle school game akin to "Where's Waldo" by posting aerial images of ice floes from the air and challenging students to try to find the seals. Visit the website at cires.colorado.edu/blogs/hmm/2010/09/09/find-the-seals/.

To view a short video of the project visit www.colorado.edu/news and click on the story headline.

For more information on CU-Boulder visit www.colorado.edu/. For more information on CIRES visit cires.colorado.edu/. For more information on NOAA visit www.noaa.gov/

Contact

Elizabeth Weatherhead, 303-497-6653
Elizabeth.Weatherhead@colorado.edu

November 3, 2010

Melt water flowing through ice sheets via crevasses, fractures and large drains called moulins can carry warmth into ice sheet interiors, greatly accelerating the thermal response of an ice sheet to climate change, according to a new study involving the University of Colorado at Boulder.

The new study showed ice sheets like the Greenland Ice Sheet can respond to such warming on the order of decades rather than the centuries projected by conventional thermal models. Ice flows more readily as it warms, so a warming climate can increase ice flows on ice sheets much faster than previously thought, said the study authors.

"We are finding that once such water flow is initiated through a new section of ice sheet, it can warm rather significantly and quickly, sometimes in just 10 years, " said lead author Thomas Phillips, a research scientist with Cooperative Institute for Research in Environmental Sciences. CIRES is a joint institute between CU-Boulder and the National Oceanic and Atmospheric Administration.

Phillips, along with CU-Boulder civil, environmental and architectural engineering Professor Harihar Rajaram and CIRES Director Konrad Steffen described their results in a paper published online this week in Geophysical Research Letters.

Conventional thermal models of ice sheets do not factor in the presence of water within the ice sheet as a warming agent, but instead use models that primarily consider ice-sheet heating by warmer air on the ice sheet surface. In water's absence, ice warms slowly in response to the increased surface temperatures from climate change, often requiring centuries to millennia to happen.

But the Greenland ice sheet is not one solid, smooth mass of ice. As the ice flows towards the coast, grating on bedrock, crevasses and new fractures form in the upper 100 feet of the ice sheet. Melt water flowing through these openings can create "ice caves" and networks of "pipes" that can carry water through the ice and spreading warmth, the authors concluded.

To quantify the influence of melt water, the scientists modeled what would happen to the ice sheet temperature if water flowed through it for eight weeks every summer -- about the length of the active melt season. The result was a significantly faster-than-expected increase in ice sheet warming, which could take place on the order of years to decades depending on the spacing of crevasses and other "pipes" that bring warmer water into the ice sheet in summer.

"The key difference between our model and previous models is that we include heat exchange between water flowing through the ice sheet and the ice," said Rajaram.

Several factors contributed to the warming and resulting acceleration of ice flow, including the fact that flowing water into the ice sheets can stay in liquid form even through the winter, slowing seasonal cooling. In addition, warmer ice sheets are more susceptible to increases of water flow, including the basal lubrication of ice that allows ice to flow more readily on bedrock.

A third factor is melt water cascading downward into the ice, which warms the surrounding ice. In this process the water can refreeze, creating additional cracks in the more vulnerable warm ice, according to the study.

Taken together, the interactions between water, temperature, and ice velocity spell even more rapid changes to ice sheets in a changing climate than currently anticipated, the authors concluded. After comparing observed temperature profiles from Greenland with the new model described in the paper, the authors concluded the observations were unexplainable unless they accounted for warming.

"The fact that the ice temperatures warm rather quickly is really the key piece that's been overlooked in models currently being used to determine how Greenland responds to climate warming," Steffen said. "However, this process is not the ‘death knell' for the ice sheet. Even under such conditions, it would still take thousands of years for the Greenland ice sheet to disappear, Steffen said.

This study was funded by NASA's Cryosphere Science Program.

Contact

Thomas Phillips, 303-492-4829
Thomas.Phillips@colorado.edu
Harihar Rajaram, 303-4926604
Konrad Steffen, 303-492-8773
Konrad.Steffen@colorado.edu
Morgan Heim, CIRES Communication, 303-492-6289
Morgan.Heim@colorado.edu

Fire and forest ecologist Tania Schoennagel and her colleagues Thomas Veblen and others conducted studies of the forests west of Boulder before the devastating Fourmile Canyon Fire erupted on September 6th, 2010. By the time the Fourmile Fire was fully contained about a week later, it had become the most destructive fire in Colorado history. Schoennagel discussed the fire, results from their studies, and ideas for future fire mitigation in an extended interview with Ryan Warner of Colorado Public Radio on 15 September.

During the interview Schoennagel notes that the forests west of Boulder were ripe for a severe fire, primarily because many of the forests in the area are naturally dense, with only minimal effects of past fire suppression on forest density. Moreover, her research shows that these forests have a long history of fire, including severe fire events. She and her colleagues identified fire scars in tree rings to create a history of past fires. Their data identifed many fire events, including severe fires that destroyed the town of Gold Hill in 1860 and another than nearly destroyed the town again in 1894. Both fires occurred during a prolonged dry period in the late 1800's.

Schoennagel and Warner discuss many topics including the difficulties of coordinating fire mitigation efforts on a patchwork of public and private lands, the expected increase in damaging wildfires in the Wildland-Urban Interface associated with increasing population and changing climate, and ideas for reducing the damage of future wildfires.

http://instaar.colorado.edu/research/science_spotlights.html#pjbr

October 20, 2010

PHOENIX, AZ—At a meeting of water leaders from the seven Colorado River Basin states in Phoenix today, Secretary of the Interior Ken Salazar announced that the Department of the Interior has chosen the University of Arizona as home base for a regional Climate Science Center and selected the Colorado River Basin for the launch of the first U.S. water census since 1978.

“The Colorado River Basin is ground zero for assessing the effects of climate change on our rivers and taking creative management actions to head off the related dangers posed to our water supplies, hydroelectric power generation and ecosystems,” the Secretary said. “We are with you for the long haul to protect our region and its water.”

The Southwest Climate Center is the fourth of eight planned regional Climate Science Centers—or CSCs--to be established by the Department. With the University of Arizona in Tucson as home base, the center will be led by a consortium of that school and others -- University of California, Davis; University of California, Los Angeles; Desert Research Institute, Reno; University of Colorado, Boulder; and the Scripps Institution of Oceanography at the University of California, San Diego.

“The consortium headed by the University of Arizona brings a wide range of scientific and impact assessment capabilities to the Southwest Climate Center because it includes institutions located in and familiar with the incredible diversity of ecosystems and human settlements and activities that characterize the U.S. Southwest,” the Secretary noted. The consortium is well versed in issues such as coastal management, drought and its impacts on people and the environment, water management in the Colorado and other Southwest rivers, and the impacts of exploding populations of bark beetles on western forests.

Selected through an open competition, the six universities announced today host the Southwest Climate Alliance, which has a combined world-class scientific expertise–including hundreds of faculty working on climate- and resource-related work essential for meeting the climate challenge. In addition to the six host institutions, the Southwest Climate Alliance also includes the following as partners: Arizona State University; Northern Arizona University; University of California, Merced; University of Nevada, Las Vegas; NASA Ames Research Center, Calif.; and the U.S. Institute for Environmental Conflict Resolution, Tucson.

In addition to the climate center announcement, the Secretary told water leaders that today’s meeting also marked the launch of the Colorado River Basin Geographic Focus Study by the U.S. Geological Survey (USGS)—Interior’s scientific experts.

The study is part of the WaterSMART Water Availability and Use Assessment for the Colorado River Basin. It is planned as a three-year, $1.5 million effort that will provide an inventory of water supply and demand, including water needed to support ecosystems, and report on significant competition over water resources and the factors causing that competition. (The “SMART” in WaterSMART stands for “Sustain and Manage America’s Resources for Tomorrow.”)

“You can’t manage a resource that you don’t measure,” Salazar said. “The WaterSMART initiative is all about measuring our water supplies and how we use them. This water census will provide crucial information to water managers to improve our efforts to wisely balance competing demands.”

BACKGROUND ON CLIMATE SCIENCE CENTERS

The Department of the Interior previously announced:

    * The Alaska Climate Science Center hosted by the University of Alaska-Fairbanks in Anchorage.
    * The Southeast Climate Science Center hosted by North Carolina State University
    * The Northwest Climate Science Center led by a consortium of three universities--Oregon State University, University of Washington and the University of Idaho.

Today’s announcement covered:

    * The Southwest Climate Science Center—University of Arizona, Tucson; University of California, Davis; University of California, Los Angeles; Desert Research Institute, Reno; University of Colorado, Boulder ; and the Scripps Institution of Oceanography at the University of California in San Diego. In addition to the six host institutions, the CSC also includes the following as partners: Arizona State University; Northern Arizona University; University of California, Merced; University of Nevada, Las Vegas; NASA Ames Research Center, Calif.; and the U.S. Institute for Environmental Conflict Resolution, Tucson.

Announcements to come include:

    * The North Central Climate Science Center—announcement by end of October
    * The Northeast, South Central, and Pacific Islands Climate Science Centers-- Interior intends to invite proposals in the spring of 2011 to host the remaining regional centers
    * Secretary Salazar initiated a coordinated climate change strategy in September 2009, with Secretarial Order 3289. The order called for establishing not only regional CSCs but also a network of “Landscape Conservation Cooperatives” that engage federal agencies, local and state partners, and the public in crafting practical, landscape-level strategies for managing climate change impacts on natural resources. Twenty-one LCCs are planned through FY 2012.

The CSCs will serve as regional “hubs” of the National Climate Change and Wildlife Science Center, located at the headquarters of Interior’s U.S. Geological Survey. USGS is taking the lead on establishing the CSCs and providing initial staffing. Ultimately, funds and staff from multiple Interior bureaus will be pooled to support these centers and ensure collaborative sharing of research results and data. Together, the CSCs and Landscape Conservation Cooperatives will assess the impacts of climate change that typically extend beyond the borders of any single national wildlife refuge, national park or Bureau of Land Management unit and identify strategies to ensure that resources across landscapes are resilient.

BACKGROUND ON USGS COLORADO RIVER BASIN GEOGRAPHIC FOCUS STUDY AND NEW NATIONAL WATER CENSUS

This Colorado River Basin Geographic Focus Study is part of the ongoing effort outlined in the WaterSMART Secretarial Order signed in February 2010. It reflects a national commitment to understanding water availability in the country and managing that resource for current and future generations. The last comprehensive assessment of water availability for our nation was in 1978 and it is overdue for a new one.

The USGS WaterSMART initiative will produce a water census for the nation, a new and on-going appraisal for water availability that links both water quality and quantity, tracks changing flow, use, and storage of water, as well as developing models and predictive tools to guide its decisions . A relatively new area of science evaluates how much water needs to be left in the streams to support important ecological values. This initiative includes a significant research and assessment effort to help wildlife managers characterize the flow needs for aquatic species and their habitat. Knowing our nation’s water “assets” and rates of use on an ongoing basis is crucial to wise management.

The USGS WaterSMART Colorado River Basin Geographic Focus Study will complement the River Basin Supply and Demand grant awarded for the Colorado Basin by the Bureau of Reclamation in 2010 and is one of three such studies on major river basins across the nation planned to begin this year. Future geographic focus areas will be identified through the application of criteria being developed as part of the implementation plan for the USGS strategic science direction focused on our nation’s water resources. A critical first step will be meetings with Colorado River Basin stakeholders to collaboratively develop a detailed scope for the effort.

Contact: Joan Moody, DOI (202) 208-6416

http://www.doi.gov/news/pressreleases/Secretary-Salazar-Launches-New-Regional-Climate-Science-Center-and-Water-Census-at-Meeting-of-Colorado-River-Basin-Water-Leaders.cfm

The Arctic sea ice cover appears to have reached its minimum extent for the year, the third-lowest recorded since satellites began measuring sea ice extent in 1979, according to the University of Colorado at Boulder's National Snow and Ice Data Center.

While this year's September minimum extent was greater than 2007 and 2008, the two record-setting and near-record-setting low years, it is still significantly below the long-term average and well outside the range of natural climate variability, according to CU-Boulder's NSIDC scientists. Most researchers believe the shrinking Arctic sea ice is tied to warming temperatures caused by an increase in human-produced greenhouse gases being pumped into Earth's atmosphere.

On Sept. 10 the sea ice extent dropped to 1.84 million square miles, or 4.76 million square kilometers, and is likely the lowest ice extent of the year as sea ice appears to have begun its annual cycle of growth.

The 2010 minimum ice extent is 93,000 square miles, or 240,000 square kilometers, above the 2008 numbers and 240,000 square miles, or 630,000 square kilometers, above the record low in 2007. The 2010 sea ice extent is 130,000 square miles, or 340,000 square kilometers, below 2009, according to Serreze.
"We are still looking at summers with an ice-free Arctic Ocean in perhaps 20 to 30 years," said Serreze, also a professor in CU-Boulder's geography department.

The 2010 minimum is 753,000 square miles, or 1.95 million square kilometers, below the 1879-2000 average minimum and 625,000 square miles, or 1.62 million square kilometers, below the 1979 to 2010 average minimum.

Since NSIDC researchers determine the minimum sea ice extent using a five-day running average, there is still a small chance the sea ice extent could fall slightly, said Serreze. CU-Boulder's NSIDC will provide more detailed information in early October with a full analysis of the 2010 Arctic ice conditions, including aspects of the melt season and conditions heading into the winter ice-growth season.

NSIDC is part of CU-Boulder's Cooperative Institute for Research in Environmental Sciences -- a joint institute of CU-Boulder and the National Oceanic and Atmospheric Administration -- and is funded primarily by NASA.

For more information contact NSIDC's Jane Beitler at 303-492-1497 or Jim Scott in the CU-Boulder Office of News Services at 303-492-3114.

Contact
Jane Beitler, NSIDC, 303-492-1497
 (Jbeitler@nsidc.org
)

Jim Scott, CU News Services, 303-492-3114
 (Jim.Scott@colorado.edu)
 

September 2, 2010

BOULDER – Professor Jeff Mitton of the CU-Boulder Ecology and Evolutionary Biology Department is hitting the road this year in an effort to educate Coloradans about the state’s pine beetle epidemic and the devastating toll the small insects are taking on Colorado’s forests.

The mountain pine beetle is in the midst of its largest epidemic in recorded history. The geographic infestation extends more than 1,000 miles, from New Mexico to the Yukon Territory.  Mitton will visit eight Colorado communities where he will offer a public presentation on the life history of pine beetles and describe the struggle between attacking beetles and trees. 

In addition to describing how tiny beetles can kill immense trees, he will discuss the role climate change has played in creating the epidemic.  Small shifts in climate have expanded the geographic range in which pine beetles can thrive and extended their life cycle from one generation per year to two.  Professor Mitton will also explain a surge in the populations of beetle predators, offering some hope for Colorado’s forests.

Mitton’s tour is sponsored by LearnMoreAboutClimate.colorado.edu, an online tool developed by CU-Boulder faculty and area scientists working in conjunction with the Office for University Outreach, which features five videos that localize climate change by pairing interviews with leading scientists and everyday Coloradans to explain how climate change is affecting our state.  The site also offers teacher-developed and –tested model lessons for middle and high school students, including one that focuses on the pine beetle epidemic.  The lessons are available at Learn More About Climate by clicking the “For Educators” tab.

During the fall semester, Mitton will make presentations at the following venues:
•    Thursday, September 23, 2010 – The Longmont Public Library at 7 p.m.
•    Tuesday, September 28, 2010 – Fort Lewis College Noble Hall, Room 125 at 7 p.m. in Durango
•    Friday, October 1, 2010 – Blue Sage Center for the Arts at 7 p.m. in Paonia
•    Tuesday, November 2, 2010 – Trinidad State Junior College in the Massari Theatre at 7 p.m.

The tour will resume during the spring semester with visits to Silverthorne, Vail, and Alamosa.  The dates and locations of these presentations have yet to be finalized.

All presentations are free and open to the public.

CONTACT:      Wynn Martens
                        303-492-4471
                        outreach@colorado.edu

August 24, 2010

A new study of the High Arctic climate roughly 50 million years ago led by the University of Colorado at Boulder helps to explain how ancient alligators and giant tortoises were able to thrive on Ellesmere Island well above the Arctic Circle, even as they endured six months of darkness each year.

The new study, which looked at temperatures during the early Eocene period 52 to 53 million years ago, also has implications for the impacts of future climate change as Arctic temperatures continue to rise, said University of Colorado at Boulder Associate Professor Jaelyn Eberle of the department of geological sciences, lead author of the study.

The team used a combination of oxygen isotope ratios from fossil bone and tooth enamel of mammals, fish and turtles that lived together on Ellesmere Island to estimate the average annual Eocene temperature for the site. They also were able to tease out temperature estimates for the warmest and coldest months of the year, critical data that should help scientists better understand past and future biodiversity in the High Arctic as the climate warms, including the geographical ranges and species richness of animals and plants.

The team concluded the average temperatures of the warmest month on Ellesmere Island during the early Eocene were from 66 to 68 degrees Fahrenheit (19-20 degrees C), while the coldest month temperature was about 32 to 38 degrees F (0-3.5 degrees C). "Our data gathered from multiple organisms indicate it probably did not get below freezing on Ellesmere Island during the early Eocene, which has some interesting implications," she said.

A paper on the subject was published in this month's issue of Earth and Planetary Science Letters. Co-authors included Henry Fricke from Colorado College, John Humphrey and Logan Hackett from the Colorado School of Mines, Michael Newbrey from University of Alberta, Edmonton, and Howard Hutchison from the University California, Berkeley. The National Science Foundation funded the study.

"This is arguably the most comprehensive data set for the early Eocene High Arctic, and certainly explains how alligators and giant tortoises could live on Ellesmere Island some 52 to 53 million years ago," said Eberle, who also is the curator of fossil vertebrates at the University of Colorado Museum of Natural History.

During the Eocene, Ellesmere Island -- which is adjacent to Greenland -- probably was similar to swampy cypress forests in the southeastern United States today, said Eberle. Eocene fossil evidence collected there in recent decades by various teams indicate the lush landscape hosted giant tortoises, aquatic turtles, large snakes, alligators, flying lemurs, tapirs, and hippo-like and rhino-like mammals.

The bone and tooth enamel of vertebrate fossils contains biogenic apatite -- a mineral that is fossilized after the death of living organisms and which can be used as a "flight recorder" to infer paleoclimate conditions. Since all of the fossil materials were from the same stratigraphic layer and locality, the oxygen isotope ratios from the animals are linked to the temperatures of both ingested river water and precipitation at the time, allowing them to better estimate temperatures in the Eocene both annually and seasonally, she said.

"We use the water that the animals were drinking as a proxy for paleotemperature," said Eberle. "In mammal fossils, for example, we can analyze the oxygen isotope ratios in a sequence along the length of a large fossil tooth and estimate the warm-month and cold-month averages during the Eocene because teeth grow year round. When it comes to oxygen isotope values in tooth enamel, what we found for these creatures is that you are what you drink," she said.

The team looked at teeth from a large, hippo-like mammal known as Coryphodon, as well as bones from bowfin fish and shells and bones from aquatic turtles from the Emydidae family, the largest and most diverse family of contemporary pond turtles. While Coryphodon and bowfins grew throughout the year, the turtles exhibited shell growth only during summer months, much like turtles that live today in non-equatorial areas.

"By looking at a host of animals with different physiologies, we were better able to pin down warm- and cold-month temperatures," she said. "Many aspects of biodiversity and species richness are related more to seasonal temperatures and ranges such as cold-month means rather than to mean annual temperature."

Bowfins -- which have a long dorsal fin and powerful jaws -- inhabit a variety of waters today from the Saint Lawrence River drainage in Quebec south to Florida and Texas. The team also compared the ranges of bowfins, aquatic turtles and giant tortoises of today with their ranges in the Eocene to help them estimate temperatures, according to co-author Newbrey, an expert in both contemporary and extinct fishes.

Eberle said the new study implies Eocene alligators could withstand slightly cooler winters than their present-day counterparts, although data from captive alligators show they are heartier than other members of the crocodilian family and can survive short intervals of subfreezing temperatures by submerging themselves in the water.

In contrast, the existence of large land tortoises in the Eocene High Arctic is still somewhat puzzling, said Eberle, since today's large tortoises inhabit places like the Galapagos Islands where the cold-month average temperature is about 50 degrees F (10 degrees C.)

But during the late Pleistocene period some 10,000 to 50,000 years ago -- when air temperatures were comparable to those today -- large land tortoises were found as far north as present-day Pennsylvania and Illinois, Eberle said. This suggests their present range in the Americas does not represent their fullest geographic range as allowed by climate. Factors like hunting by early Native Americans and the past extent of glaciers probably are playing a role in today's distribution of giant tortoises, she said.

Eberle, who calls the new results "a deep time analogue" for today's rapidly warming Arctic region, said quantitative estimates of early Eocene climate conditions at high latitudes like Ellesmere Island are rare and often contradictory. Previous estimates of the early Eocene mean annual temperatures have ranged from 39 to 68 degrees F (4 to 20 degrees C), a temperature range equivalent to geographic ranges reaching from Canada to Florida.

There is high concern by scientists over a proposal to mine coal on Ellesmere Island at the ancient fossil site by WestStar Resources Inc. headquartered in Vancouver, British Columbia, Eberle said. "Sites like this are unique and extremely valuable resources that are of international importance, and shouldn't be allowed to disappear," she said. "Our concern is that coal mining activities could damage such sites and they will be lost forever."

Today Ellesmere Island is one of the coldest, driest environments on Earth and features tundra, permafrost, ice sheets, sparse vegetation and few mammals. The temperatures range from roughly minus 37 degrees F in winter (minus 38 C) to 48 degrees F (8 degrees C) in summer.

The new study foreshadows the impacts of continuing global warming on Arctic plants and animals, Eberle said. Temperatures in the Arctic are rising twice as fast as those at mid-latitudes as greenhouse gases build up in Earth's atmosphere, due primarily to human activities like fossil fuel burning and deforestation, according to climate scientists.

Contact

Jaelyn Eberle, 303-492-8069
Jaelyn.Eberle@colorado.edu
Jim Scott, 303-492-3114
Jim.Scott@colorado.edu

An international science team involving the University of Colorado at Boulder that is working on the North Greenland Eemian Ice Drilling project hit bedrock July 27 after two summers of work, drilling down more than 1.5 miles in an effort to help assess the risks of abrupt future climate change on Earth.

Led by Denmark and the United States, the team recovered ice from the Eemian interglacial period from about 115,000 to 130,000 years ago, a time when temperatures were 3.6 to 5.4 degrees Fahrenheit above today's temperatures. During the Eemian -- the most recent interglacial period on Earth -- there was substantially less ice on Greenland, and sea levels were more than 15 feet higher than today.

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. The new effort, known as NEEM, has allowed researchers to obtain thicker, more intact annual ice layers near the bottom of the core that are expected to contain crucial information about how Earth's climate functions, said CU-Boulder Professor Jim White, lead U.S. investigator on the project.

"Scientists from 14 countries have come together in a common effort to provide the science our leaders and policy makers need to plan for our collective future," said White, who directs CU-Boulder's Institute of Arctic and Alpine Research and is an internationally known ice core expert. "I hope that NEEM is a foretaste of the kind of cooperation we need for the future, because we all share the world."

Annual ice layers formed over millennia in Greenland by compressed snow reveal information on past temperatures and precipitation levels, as well as the contents of ancient atmospheres, said White. Ice cores from previous drilling efforts revealed temperature spikes of more than 20 degrees Fahrenheit in just 50 years in the Northern Hemisphere.

White said the new NEEM ice cores will more accurately portray past changes in temperatures and greenhouse gas concentrations in the Eemian, making it the best analogue for future climate change on Earth. An international study released by the National Oceanic and Atmospheric Administration last week showed the first decade of the 21st century was the warmest on record for the planet.

The NEEM project involves 300 scientists and students and is led by Professor Dorthe Dahl-Jensen, director of the University of Copenhagen's Centre of Ice and Climate. The United States portion of the effort is funded by the National Science Foundation's Office of Polar Programs.

The two meters of ice just above bedrock from NEEM -- which is located at one of the most inaccessible parts of the Greenland ice sheet -- go beyond the Eemian interglacial period into the previous ice age and contains rocks and other material that have not seen sunlight for hundreds of thousands of years, said White. The researchers expect the cores to be rich in DNA and pollen that can tell scientists about the plants that existed in Greenland before it became covered with ice.

The cores samples are being studied in detail using a suite of measurements, including stable water isotopes that reveal information about temperature and moisture changes back in time. The team is using state-of-the art laser instruments to measure the isotopes, as well as atmospheric gas bubbles trapped in the ice and ice crystals to understand past variations in climate on a year-by-year basis, said White.

As part of the project, the researchers want to determine how much smaller the Greenland ice sheet was 120,000 years ago when the temperatures were higher than present, as well as how much and how fast the Greenland ice sheet contributed to sea level. "We expect that our findings will increase our knowledge on the future climate system and increase our ability to predict the speed and final height of sea level rise during the Eemian," said Dahl-Jensen.

The NEEM facility includes a large dome, a drilling rig to extract 3-inch in diameter ice cores, drilling trenches, labs and living quarters. The United States is leading the laboratory analysis of atmospheric gases trapped in bubbles within the cores, including greenhouse gases like carbon dioxide and methane.
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.

Other CU-Boulder participants include postdoctoral researcher Vasilii Petrenko and doctoral student Tyler Jones. White also is a professor in CU-Boulder's geological sciences department.

The vast majority of climate scientists attribute rising temperatures on Earth to increased greenhouse gases pumped into the atmosphere as a result of human activity. In 2008 The Intergovernmental Panel on Climate Change concluded that temperatures on Earth could rise by as much as 10 degrees F above today's temperatures in the next century, primarily due to atmospheric greenhouse gases.

Additional information and photos on the NEEM effort can be found on the web at http:// www.neem.ku.dk.

More information on the international NEEM deep drilling project can be obtained either by emailing White or contacting NEEM Field Operation Manager J.P. Steffensen at +299 84 11 51 or +299 52 41 25 or emailing him at neem-fom@gfy.ku.dk
-CU-

Contact
Jim White, 303-492-5494
James.White@colorado.edu
Jim Scott, 303-492-3114

Jim.Scott@colorado.edu