Author: Outreach Office
National Science Teachers Association (NSTA) teachers have a unique opportunity to request complimentary tickets for showings of the new documentary "Chasing Ice" at Chez Artiste in Denver, November 23-29th.
"Chasing Ice," one of the biggest environmental films of the year, follows acclaimed environmental photographer James Balog to the Arctic where he captures time-lapse images of the world's changing glaciers in the face of climate change. University of Colorado Boulder professors served on a team of science advisors for the film, including Jim White who is featured in our Learn More about Climate (LMAC) video series.
Chasing Ice has won nearly 20 awards at film festivals around the world, including: The Sundance Film Festival – Excellence in Cinematography Award: US Documentary and the Environmental Media Association’s 22nd Annual Best Documentary Award. For more information about the film and to watch the trailer, visit http://www.chasingice.com/
Ticket requests are fulfilled on a first-come, first served basis and admission is not guaranteed. To request tickets, fill out the form at http://bit.ly/icetickets. Please use the code "COLOED" on the request form.
November 5, 2012
A new University of Colorado Boulder study shows for the first time that episodes of reduced precipitation in the southern Rocky Mountains, especially during the 2001-02 drought, greatly accelerated development of the mountain pine beetle epidemic.
The study, the first ever to chart the evolution of the current pine beetle epidemic in the southern Rocky Mountains, compared patterns of beetle outbreak in the two primary host species, the ponderosa pine and lodgepole pine, said CU-Boulder doctoral student Teresa Chapman. The current mountain pine beetle outbreak in the southern Rockies -- which range from southern Wyoming through Colorado and into northern New Mexico --is estimated to have impacted nearly 3,000 square miles of forests, said Chapman, lead study author.
While the 2001-02 drought in the West played a key role in pushing the pine beetle outbreak into a true regional epidemic, the outbreak continued to gain ground even after temperature and precipitation levels returned to levels nearer the long-term averages, said Chapman of CU-Boulder’s geography department. The beetles continued to decimate lodgepole pine forests by moving into wetter and higher elevations and into less susceptible tree stands -- those with smaller diameter lodgepoles sharing space with other tree species.
“In recent years some researchers have thought the pine beetle outbreak in the southern Rocky Mountains might have started in one place and spread from there,” said Chapman. “What we found was that the mountain pine beetle outbreak originated in many locations. The idea that the outbreak spread from multiple places, then coalesced and continued spreading, really highlights the importance of the broad-scale drivers of the pine beetle epidemic like climate and drought.”
A paper on the subject was recently published in the journal Ecology. Co-authors on the study include CU-Boulder geography Professor Thomas Veblen and Tania Schoennagel, an adjunct faculty member in the geography department and a research scientist at CU-Boulder’s Institute of Arctic and Alpine Research. The National Science Foundation funded the study.
Mountain pine beetles are native insects that have shaped the forests of North America for thousands of years. They range from Canada to Mexico and are found at elevations from sea level to 11,000 feet. The effects of pine beetles are especially evident in recent years on Colorado’s Western Slope, including Rocky Mountain National Park, with a particularly severe epidemic occurring in Grand and Routt counties.
Chapman said the most recent mountain pine beetle outbreak began in the 1990s, primarily in scattered groups of lodgepole pine trees living at low elevations in areas of lower annual precipitation. Following the 2001-02 drought, the outbreak was “uncoupled” from the initial weather and landscape conditions, triggering a rise in beetle populations on the Western Slope and propelling the insects over the Continental Divide into the northern Front Range to infect ponderosa pine, Chapman said.
The current pine beetle epidemic in the southern Rocky Mountains was influenced in part by extensive forest fires that ravaged Colorado’s Western Slope from roughly 1850 to 1890, said Chapman. Lodgepole pine stands completely burned off by the fires were succeeded by huge swaths of seedling lodgepoles that eventually grew side by side into dense mature stands, making them easier targets for the pine beetles.
“The widespread burning associated with dry years in the 19th century set the stage for the current outbreak by creating vast areas of trees in the size classes most susceptible to beetle attack,” said Chapman.
Veblen said a 1980s outbreak of the pine beetle centered in Colorado’s Grand County ended when extremely low minimum temperatures were reached in the winters of 1983 and 1984, killing the beetle larvae. But during the current outbreak, minimum temperatures during all seasons have been persistently high since 1996, well above the levels of extreme cold shown to kill beetle larvae in laboratory experiments.
“This implies that under continued warming trends, future outbreaks will not be terminated until they exhaust their food supply -- the pine tree hosts,” said Veblen.
Chapman said there has been a massive and unprecedented beetle epidemic in British Columbia, which also began in the early 1990s and has now has affected nearly 70,000 square miles. “It is hard to tell if this current beetle epidemic in the Southern Rockies is unprecedented,” she said. “While warm periods in the 16th century may have triggered a large beetle epidemic, any evidence would have been wiped out by the massive fires in the latter part of the 19th century.”
Veblen said while the rate of spread of the mountain pine beetle in lodgepole pine forests has declined in the southern Rocky Mountains during the past two years because of a depletion of host pine population, U.S. Forest Service surveys indicate the rate of beetle spread in ponderosa pine forests on the Front Range has increased sharply over the past three years. “The current study suggests that under the continued warmer climate, the spread of the beetle in ponderosa pines is likely to grow until that food source also is depleted,” Veblen said.
“Our results emphasize the importance of considering different patterns in the population dynamics of mountain pine beetles for different host species, even under similar regional-scale weather variations,” said Chapman. “Given the current outbreak of mountain pine beetles on the Front Range, their impact on ponderosa pines is certainly something that needs further study.”
A 2012 study by CU-Boulder Professor Jeffry Mitton and graduate student Scott Ferrenberg showed some Colorado pine beetles, which had been known to produce only one generation of tree-killing offspring annually, are producing two generations per year due to rising temperatures and a longer annual warm season. Because of the extra annual generation of beetles, there could be up to 60 times as many beetles attacking trees in any given year, according to the study.
In addition, a 2011 study led by CU-Boulder graduate student Evan Pugh indicated the infestation of trees by mountain pine beetles in the high country across the West could potentially trigger earlier snowmelt and increase water yields from snowpack that accumulates beneath affected trees.
Contact: Teresa Chapman, 303-492-4785
Thomas Veblen, 303-492-8528
While a new study led by the University of Colorado Boulder shows the risk of human conflict in East Africa increases somewhat with hotter temperatures and drops a bit with higher precipitation, it concludes that socioeconomic, political and geographic factors play a much more substantial role than climate change.
According to CU-Boulder geography Professor John O’Loughlin, the new CU-Boulder study undertaken with the National Center for Atmospheric Research in Boulder is an attempt to clarify the often-contradictory debate on whether climate change is affecting armed conflicts in Africa. “We wanted to get beyond the specific idea and hype of climate wars,” he said. “The idea was to bring together a team perspective to see if changes in rainfall and temperature led to more conflict in vulnerable areas of East Africa.”
The research team examined extensive climate datasets from nine countries in East Africa, including the Horn of Africa, between 1990 and 2009: Burundi, Djibouti, Eritrea, Ethiopia, Kenya, Rwanda, Somalia, Tanzania and Uganda. The team also used a dataset containing more than 16,000 violent conflicts in those countries during that time period, parsing out more specific information on conflict location and under what type of political, social, economic and geographic conditions each incident took place.
The study, which included changes in precipitation and temperature over continuous six-month periods from 1949 to 2009, also showed there was no climate effect on East African conflicts during normal and drier precipitation periods or during periods of average and cooler temperatures, said O’Loughlin.
Moderate increases in temperature reduced the risk of conflict slightly after controlling for the influence of social and political conditions, but very hot temperatures increased the risk of conflict, said O’Loughlin. Unusually wet periods also reduced the risk of conflict, according to the new study.
“The relationship between climate change and conflict in East Africa is incredibly complex and varies hugely by country and time period,” he said. “The simplistic arguments we hear on both sides are not accurate, especially those by pessimists who talk about ‘climate wars’. Compared to social, economic and political factors, climate factors adding to conflict risk are really quite modest.”
The results are being published online Oct. 22 in the Proceedings of the National Academy of Sciences. Co-authors on the study include CU-Boulder Research Associate Frank Witmer and graduate student Andrew Linke as well as three scientists from the National Center for Atmospheric research -- Arlene Laing, Andrew Gettelman and Jimy Dudhia. The National Science Foundation funded the study.
Much of the information on the 16,359 violent events in East Africa from 1990 to 2009 came from the Armed Conflict Location and Event Dataset, or ACLED, directed by Clionadh Raleigh of Trinity College in Dublin. The database covers individual conflicts from 1997 to 2009 in Africa, parts of Asia and Haiti – more than 60,000 violent incidents to date. Raleigh started the data collection while earning her doctorate at CU in 2007 under O’Loughlin.
In addition, more than a dozen CU-Boulder undergraduates spent thousands of hours combing online information sources like LexisNexis -- a corporation that pioneered the electronic accessibility of legal and newspaper documents -- in order to fill in details of individual violent conflicts by East African countries from 1990 to 1997. The student work was funded by the NSF’s Research Experiences for Undergraduates program.
The CU students coded each conflict event with very specific data, including geographic location coordinates, dates, people and descriptive classifications. The event information was then aggregated into months and into 100-kilometer grid cells that serve as the units of analysis for quantitative modeling.
Each conflict grid also was coded by socioeconomic and political characteristics like ethnic leadership, distance to an international border, capital city, local population size, well-being as measured by infant mortality, the extent of political rights, presidential election activity, road network density, the health of vegetation and crop conditions.
“The effects of climate variability on conflict risk is different in different countries,” O’Loughlin said. “Typically conflicts are very local and quite confined. The effects of climate on conflict in Ethiopia, for example, are different than those in Tanzania or Somalia. The idea that there is a general ‘African effect’ for conflict is wrong.”
The researchers used a variety of complex statistical calculations to assess the role of climate in violent conflict in East Africa, including regression models and a technique to uncover nonlinear influences and decrease “noise,” said O’Loughlin, also a faculty member at CU-Boulder’s Institute of Behavioral Science.
One component of the methods used by the team extracts predictions of individual instances of conflict from the statistical model and systematically compared them with the actual observations of conflict in the data, “a rigorous validity check,” he said.
Catastrophic conflicts like those in the “Great Lakes region” -- Rwanda, Burundi, Uganda and the eastern Democratic Republic of the Congo -- since the 1990s and the war with the Lord’s Resistance Army led by terrorist Joseph Kony that has been running since the late 1980s in northern Uganda and neighboring regions are marked with large red swaths on the maps.
Legacies of violence are extremely important for understanding and explaining unrest, he said. “Violence nearby and prior violence in the locality, especially for heavily populated areas, are the strongest predictors of conflict.”
Ongoing work is extending the study to all of sub-Saharan Africa since 1980 with a database of 63,000 violent events. Preliminary results from the work confirm the East African climate effects of higher than normal temperatures are increasing conflict risk.
John O’Loughlin, 303-492-1619
Press release from The National Snow and Ice Data Center (NSIDC), part of the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder. NSIDC scientists provide Arctic Sea Ice News & Analysis content, with partial support from NASA.
October 2, 2012
This September, sea ice covering the Arctic Ocean fell to the lowest extent in the satellite record, which began in 1979. Satellite data analyzed by NSIDC scientists showed that the sea ice cover reached its lowest extent on September 16. Sea ice extent averaged for the month of September was also the lowest in the satellite record.
The near-record ice melt occurred without the unusual weather conditions that contributed to the extreme melt of 2007. In 2007, winds and weather patterns helped melt large expanses of ice. "Atmospheric and oceanic conditions were not as conducive to ice loss this year, but the melt still reached a new record low," said NSIDC scientist Walt Meier. "This probably reflects loss of multi-year ice in the Arctic, as well as other factors that are making the ice more vulnerable." Multi-year ice is ice that has survived more than one melt season and is thicker than first-year ice.
NSIDC Director Mark Serreze said, "It looks like the spring ice cover is so thin now that large areas melt out in summer, even without persistent extreme weather patterns." A storm that tracked through the Arctic in August helped break up the weakened ice pack.
Arctic sea ice extent reached its lowest point this year on September 16, 2012 when sea ice extent dropped to 3.41 million square kilometers (1.32 million square miles). Averaged over the month of September, ice extent was 3.61 million square kilometers (1.39 million square miles). This places 2012 as the lowest ice extent both for the daily minimum extent and the monthly average. Ice extent was 3.29 million square kilometers (1.27 million square miles) below the 1979 to 2000 average.
The Arctic ice cap grows each winter as the sun sets for several months and shrinks each summer as the sun rises higher in the northern sky. Each year the Arctic sea ice reaches its annual minimum extent in September. It hit its previous record low in 2007. This summer's low ice extent continued the downward trend seen over the last 33 years. Scientists attribute this trend in large part to warming temperatures caused by climate change. Since 1979, September Arctic sea ice extent has declined by 13 percent per decade. Summer sea ice extent is important because, among other things, it reflects sunlight, keeping the Arctic region cool and moderating global climate.
In addition to the decline in sea ice extent, a two-dimensional measure of the ice cover, the ice cover has grown thinner and less resistant to summer melt. Recent data on the age of sea ice, which scientists use to estimate the thickness of the ice cover, shows that the youngest, thinnest ice, which has survived only one or two melt seasons, now makes up the large majority of the ice cover.
Climate models have suggested that the Arctic could lose almost all of its summer ice cover by 2100, but in recent years, ice extent has declined faster than the models predicted. Serreze said, "The big summer ice loss in 2011 set us up for another big melt year in 2012. We may be looking at an Arctic Ocean essentially free of summer ice only a few decades from now." NSIDC scientist Julienne Stroeve recently spent three weeks in the Arctic Ocean on an icebreaker ship, and was surprised by how thin the ice was and how much open water existed between the individual ice floes. "According to the satellite data, I expected to be in nearly 90% ice cover, but instead the ice concentrations were typically below 50%," she said.
As the Arctic was experiencing a record low minimum extent, the Antarctic sea ice was reaching record high levels, culminating in a Southern Hemisphere winter maximum extent of 19.44 million square kilometers (7.51 million square miles) on September 26. The September 2012 monthly average was also a record high, at 19.39 million square kilometers (7.49 million square miles) slightly higher than the previous record in 2006. Temperatures over Antarctica were near average this austral winter. Scientists largely attribute the increase in Antarctic sea ice extent to stronger circumpolar winds, which blow the sea ice outward, increasing extent.
NSIDC scientist Ted Scambos said, "Antarctica's changes—in winter, in the sea ice—are due more to wind than to warmth, because the warming does not take much of the sea ice area above the freezing point during winter. Instead, the winds that blow around the continent, the "westerlies," have gotten stronger in response to a stubbornly cold continent, and the warming ocean and land to the north."
Information and graphics
For a full analysis of the summer melt season and additional images, please see Arctic Sea Ice News and Analysis.
An NSIDC animation of the Arctic melt season is available at: http://www.youtube.com/watch?v=AztEry44A9A&feature=youtu.be
An NSIDC animation of the Antarctic melt season is available at http://www.youtube.com/watch?v=CBD8hWbiFMI&feature=youtu.be
For more information and visualizations of thinning sea ice, see the NOAA Climate Watch article, "Arctic Sea Ice Getting Thinner, Younger."
National Snow and Ice Data Center
University of Colorado Boulder
The International Collective on Environment, Culture, and Politics ICE CaPs is hosting an event on October 12th called "Between God and Green: How Evangelicals are Cultivating a Middle Ground on Climate Change" based on Katharine Wilkinson's Oxford University Press book (book information here)
Who: Dr. Katharine Wilkinson
When: Friday, October 12, 5:00 - 6:30 pm
Where: Old Main Chapel, CU-Boulder
Why: The first event for the emergent International Collective on Environment, Culture and Politics (ICE CaPs): ICE CaPs seeks to promote the development of workable and effective responses to complexenvironmental challenges from the local to the international, and to provoke public engagement with these issues. see www.icecaps.org for more information.
A new University of Colorado Boulder-led study that ties forest “greenness” in the western United States to fluctuating year-to-year snowpack indicates mid-elevation mountain ecosystems are most sensitive to rising temperatures and changes in precipitation and snowmelt.
Led by CU-Boulder researcher Ernesto Trujillo and Assistant Professor Noah Molotch, the study team used the data -- including satellite images and ground measurements -- to identify the threshold where mid-level forests sustained primarily by moisture change to higher-elevation forests sustained primarily by sunlight and temperature. Being able to identify this “tipping point” is important because it is in the mid-level forests -- at altitudes from roughly 6,500 to 8,000 feet -- where many people live and play in the West and which are associated with increasing wildfires, beetle outbreaks and increased tree mortality, said Molotch.
“Our results provide the first direct observations of the snowpack-forest connections across broad spatial scales,” said Molotch, also a research scientist at CU-Boulder’s Institute of Arctic and Alpine Research. “Finding the tipping point between water-limited forests and energy-limited forests defines for us the region of the greatest sensitivity to climate change -- the mid-elevation forests -- which is where we should focus future research.”
While the research by Molotch and his team took place in the Sierra Nevada mountain range in California, it is applicable to other mountain ranges across the West, he said. The implications are important, since climate studies indicate the snowpack in mid-elevation forests in the Western United States and other similar forests around the world has been decreasing in the past 50 years because of regional warming.
“We found that mid-elevation forests show a dramatic sensitivity to snow that fell the previous winter in terms of accumulation and subsequent melt,” said Molotch, also a scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “If snowpack declines, forests become more stressed, which can lead to ecological changes that include alterations in the distribution and abundance of plant and animal species as well as vulnerability to perturbations like fire and beetle kill.”
A paper on the subject was published online Sept. 9 in Nature Geosciences. Co-authors on the study include Ernesto Trujillo of INSTAAR and the Ecole Polytechnique Fédérale de Lausanne in Switzerland, Michael Golden and Anne Kelly of the University of California, Irvine, and Roger Bales of the University of California, Merced. The National Science Foundation and NASA funded the study.
Molotch said the study team attributed about 50 percent of the greenness in mid-elevation forests by satellites to maximum snow accumulation from the previous winter, with the other 50 percent caused by conditions like soil depth, soil nutrients, temperature and sunlight. “The strength of the relationship between forest greenness and snowpack from the previous year was quite surprising to us,” Molotch said.
The research team initially set out to identify the various components of drought that lead to vegetation stress, particularly in mountain snowpack, said Molotch. “We went after snowpack in the western U.S. because it provides about 60 to 80 percent of the water input in high elevation mountains.”
The team used 26 years of continuous data from the Advanced Very High Resolution Radiometer, a space-borne sensor flying on a National Oceanic and Atmospheric Administration satellite, to measure the forest greenness. The researchers compared it to long-term data from 107 snow stations maintained by the California Cooperative Snow Survey, a consortium of state and federal agencies.
In addition, the researchers used information gathered from several “flux towers” in the southern Sierra Nevada mountain range, which measure the exchanges of carbon dioxide, water vapor and energy between terrestrial ecosystems and the atmosphere. Instruments on the towers, which are roughly 100 feet high, allowed them to measure the sensitivity of both mid-level and high-level mountainous regions in both wet and dry years -- data that matched up well with the satellite and ground data, he said.
“The implications of this study are profound when you think about the potential for ecological change in mountainous environments in the West in the not too distant future,” said Molotch, an assistant professor in the geography department. “If we take our study and project forward in time when climate models are calling for warming and drying conditions, the implication is that forests will be increasingly water-stressed in the future and thus more vulnerable to fires and insect outbreaks.
“When you put this into the context of recent losses in Colorado and elsewhere in the West to forest fire devastation, then it becomes something we really have to pay attention to,” he said. “This tipping-point elevation is very likely to migrate up the mountainsides as the climate warms.”
Noah Molotch, 303-492-6151
Warmer air temperatures since the 1980s may explain significant increases in zinc and other metal concentrations of ecological concern in a Rocky Mountain watershed, reports a new study led by the U.S. Geological Survey and the University of Colorado Boulder.
Rising concentrations of zinc and other metals in the upper Snake River just west of the Continental Divide near Keystone, Colo., may be the result of falling water tables, melting permafrost and accelerating mineral weathering rates, all driven by warmer air temperatures in the watershed. Researchers observed a fourfold increase in dissolved zinc over the last 30 years during the month of September.
Increases in metals were seen in other months as well, with lesser increases seen during the high-flow snowmelt period. During the study period, local mean annual and mean summer air temperatures increased at a rate of 0.5 to 2.2 degrees Fahrenheit per decade.
Generally, high concentrations of dissolved metals in the Snake River watershed are primarily the result of acid rock drainage, or ARD, formed by natural weathering of pyrite and other metal-rich sulfide minerals in the bedrock. Weathering of pyrite forms sulfuric acid through a series of chemical reactions, and pulls metals like zinc from minerals in the rock and carries these metals into streams.
Increased sulfate and calcium concentrations observed over the study period lend weight to the hypothesis that the increased zinc concentrations are due to acceleration of pyrite weathering. The potential for comparable increases in metals in similar Western watersheds is a concern because of impacts on water resources, fisheries and stream ecosystems. Trout populations in the lower Snake River, for example, appear to be limited by the metal concentrations in the water, said USGS research biologist Andrew Todd, lead researcher on the project.
“Acid rock drainage is a significant water quality problem facing much of the Western United States,” Todd said. “It is now clear that we need to better understand the relationship between climate and ARD as we consider the management of these watersheds moving forward.”
Warmer temperatures and earlier snowmelt runoff have been observed throughout mountainous areas of the western United States where ARD is common, but it is not known if these changes have triggered rising acidity and metal concentrations in other “mineralized” watersheds because of lack of comparable monitoring data, according to the research team.
CU-Boulder Professor Diane McKnight, a collaborator on the project, has generated much of the upper Snake River data through research projects conducted with her students since the mid-1990s. McKnight said students in her environmental engineering and environmental studies classes like Caitlin Crouch -- a study co-author who received her master’s degree under McKnight -- are highly motivated to understand ARD problems.
“Students can see that their research will have direct applications to addressing a critical issue for Colorado,” said McKnight, professor in the civil, environmental and architectural engineering department and a fellow in CU’s Institute of Arctic and Alpine Research.
In cases where ARD is linked directly with past and present mining activities it is called acid mine drainage, or AMD. Another Snake River tributary, Peru Creek, is largely devoid of life due to AMD generated from the abandoned Pennsylvania Mine and smaller mines upstream and has become a target for potential remediation efforts.
The Colorado Division of Reclamation Mining and Safety, in conjunction with other local, state and federal partners, is conducting underground exploration work at the mine to investigate the sources of heavy metals-laden water draining from the mine entrance. The new study by Todd and colleagues has important implications in such mine cleanup efforts because it suggests that establishing attainable cleanup objectives could be difficult if natural background metal concentrations are a “moving target.”
A study on the subject was published in the journal Environmental Science and Technology. Other collaborators include Andrew Manning and Philip Verplanck of USGS. The data analyzed for the study came from INSTAAR, the USGS and the U.S. Environmental Protection Agency.
Heidi Koontz, USGS, 303-202-4763
Diane McKnight, CU-Boulder, 303-492-4687
August 27, 2012
When the Fourmile Canyon Fire erupted west of Boulder in 2010, smoke from the wildfire poured into parts of the city including a site housing scientists from the University of Colorado Boulder’s Cooperative Institute for Research in Environmental Sciences and the National Oceanic and Atmospheric Administration.
Within 24 hours, a few researchers at the David Skaggs Research Center had opened up a particle sampling port on the roof of the building and started pulling in smoky air for analysis by two custom instruments inside. They became the first scientists to directly measure and quantify some unique heat-trapping effects of wildfire smoke particles.
“For the first time we were able to measure these warming effects minute-by-minute as the fire progressed,” said CIRES scientist Dan Lack, lead author of the study published today in the Proceedings of the National Academy of Sciences.
The researchers also were able to record a phenomenon called the “lensing effect,” in which oils from the fire coat the soot particles and create a lens that focuses more light onto the particles. This can change the “radiative balance” in an area, sometimes leading to greater warming of the air and cooling of the surface.
While scientists had previously predicted such an effect and demonstrated it in laboratory experiments, the Boulder researchers were one of the first to directly measure the effect during an actual wildfire. Lack and his colleagues found that lensing increased the warming effect of soot by 50 to 70 percent.
“When the fire erupted on Labor Day, so many researchers came in to work to turn on instruments and start sampling that we practically had traffic jams on the road into the lab,” Lack said. “I think we all realized that although this was an unfortunate event, it might be the best opportunity to collect some unique data. It turned out to be the best dataset, perfectly suited to the new instrument we had developed.”
The instrument called a spectrophotometer can capture exquisite detail about all particles in the air, including characteristics that might affect the smoke particles’ tendency to absorb sunlight and warm their surroundings. While researchers know that overall, wildfire smoke can cause this lensing effect, the details have been difficult to quantify, in part because of sparse observations of particles from real-world fires.
Once the researchers began studying the data they collected during the fire, it became obvious that the soot from the wildfire was different in several key ways from soot produced by other sources -- diesel engines, for example.
“When vegetation burns, it is not as efficient as a diesel engine, and that means some of the burning vegetation ends up as oils,” Lack said. In the smoke plume, the oils coated the soot particles and that microscopic sheen acted like a magnifying glass, focusing more light onto the soot particles and magnifying the warming of the surrounding air.
The researchers also discovered that the oils coating the soot were brown, and that dark coloration allowed further absorption of light, and therefore further warming the atmosphere around the smoke plume.
The additional warming effects mean greater heating of the atmosphere enveloped in dark smoke from a wildfire, and understanding that heating effect is important for understanding climate change, Lack said. The extra heating also can affect cloud formation, air turbulence, winds and even rainfall.
The discovery was made possible by state-of-the-art instruments developed by CIRES, NOAA and other scientists, Lack said. The instruments can capture fine-scale details about particles sent airborne by the fire, including their composition, shape, size, color and ability to absorb and reflect sunlight of various wavelengths.
“With such well-directed measurements, we can look at the warming effects of soot, the magnifying coating and the brown oils and see a much clearer, yet still smoky picture of the effect of forest fires on climate,” Lack said.
CIRES is a cooperative institute of CU-Boulder and NOAA.
Dan Lack, 303-497-5824
Jane Palmer, CIRES media relations, 303-492-6289
August 27, 2012
The blanket of sea ice floating on the Arctic Ocean melted to its lowest extent ever recorded since satellites began measuring it in 1979, according to the University of Colorado Boulder’s National Snow and Ice Data Center.
On Aug. 26, the Arctic sea ice extent fell to 1.58 million square miles, or 4.10 million square kilometers. The number is 27,000 square miles, or 70,000 square kilometers below the record low daily sea ice extent set Sept. 18, 2007. Since the summer Arctic sea ice minimum normally does not occur until the melt season ends in mid- to late September, the CU-Boulder research team expects the sea ice extent to continue to dwindle for the next two or three weeks, said Walt Meier, an NSID scientist.
“It’s a little surprising to see the 2012 Arctic sea ice extent in August dip below the record low 2007 sea ice extent in September,” he said. “It’s likely we are going to surpass the record decline by a fair amount this year by the time all is said and done.”
On Sept. 18, 2007, the September minimum extent of Arctic sea ice shattered all satellite records, reaching a five-day running average of 1.61 million square miles, or 4.17 million square kilometers. Compared to the long-term minimum average from 1979 to 2000, the 2007 minimum extent was lower by about a million square miles -- an area about the same as Alaska and Texas combined, or 10 United Kingdoms.
While a large Arctic storm in early August appears to have helped to break up some of the 2012 sea ice and helped it to melt more quickly, the decline seen in in recent years is well outside the range of natural climate variability, said Meier. Most scientists believe the shrinking Arctic sea ice is tied to warming temperatures caused by an increase in human-produced greenhouse gases pumped into Earth’s atmosphere.
CU-Boulder researchers say the old, thick multi-year ice that used to dominate the Arctic region has been replaced by young, thin ice that has survived only one or two melt seasons -- ice which now makes up about 80 percent of the ice cover. Since 1979, the September Arctic sea ice extent has declined by 12 percent per decade.
The record-breaking Arctic sea ice extent in 2012 moves the 2011 sea ice extent minimum from the second to the third lowest spot on record, behind 2007. Meier and his CU-Boulder colleagues say they believe the Arctic may be ice-free in the summers within the next several decades.
“The years from 2007 to 2012 are the six lowest years in terms of Arctic sea ice extent in the satellite record,” said Meier. “In the big picture, 2012 is just another year in the sequence of declining sea ice. We have been seeing a trend toward decreasing minimum Arctic sea ice extents for the past 34 years, and there’s no reason to believe this trend will change.”
The Arctic sea ice extent as measured by scientists is the total area of all Arctic regions where ice covers at least 15 percent of the ocean surface, said Meier.
Scientists say Arctic sea ice is important because it keeps the polar region cold and helps moderate global climate -- some have dubbed it “Earth’s air conditioner.” While the bright surface of Arctic sea ice reflects up to 80 percent of the sunlight back to space, the increasing amounts of open ocean there -- which absorb about 90 percent of the sunlight striking the Arctic -- have created a positive feedback effect, causing the ocean to heat up and contribute to increased sea ice melt.
Earlier this year, a national research team led by CU embarked on a two-year effort to better understand the impacts of environmental factors associated with the continuing decline of sea ice in the Arctic Ocean. The $3 million, NASA-funded project led by Research Professor James Maslanik of aerospace engineering sciences includes tools ranging from unmanned aircraft and satellites to ocean buoys in order to understand the characteristics and changes in Arctic sea ice, including the Beaufort Sea and Canada Basin that are experiencing record warming and decreased sea ice extent.
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 headquartered on the CU campus -- and is funded primarily by NASA. NSIDC’s sea ice data come from the Special Sensor Microwave Imager/Sounder sensor on the Defense Meteorological Satellite Program F17 satellite using methods developed at NASA’s Goddard Space Flight Center in Greenbelt, Md.
For more information and graphics visit CU-Boulder’s NSIDC website at http://nsidc.org/arcticseaicenews/2011/091511.html. For more information on CIRES visit http://cires.colorado.edu/.
Natasha Vizcarra, NSIDC news, 303-492-1497
August 1, 2012
Despite sharp increases in carbon dioxide emissions by humans in recent decades that are warming the planet, Earth’s vegetation and oceans continue to soak up about half of them, according to a surprising new study led by the University of Colorado Boulder.
The study, led by CU-Boulder postdoctoral researcher Ashley Ballantyne, looked at global CO2 emissions reports from the past 50 years and compared them with rising levels of CO2 in Earth’s atmosphere during that time, primarily because of fossil fuel burning. The results showed that while CO2 emissions had quadrupled, natural carbon “sinks” that sequester the greenhouse gas doubled their uptake in the past 50 years, lessening the warming impacts on Earth’s climate.
“What we are seeing is that the Earth continues to do the heavy lifting by taking up huge amounts of carbon dioxide, even while humans have done very little to reduce carbon emissions,” said Ballantyne. “How long this will continue, we don’t know.”
A paper on the subject will be published in the Aug. 2 issue of Nature. Co-authors on the study include CU-Boulder Professor Jim White, CU-Boulder doctoral student Caroline Alden and National Oceanic and Atmospheric Administration scientists John Miller and Pieter Tans. Miller also is a research associate at the CU-headquartered Cooperative Institute for Research in Environmental Sciences.
According to Alden, the trend of sinks gulping atmospheric carbon cannot continue indefinitely. “It’s not a question of whether or not natural sinks will slow their uptake of carbon, but when,” she said.
“We’re already seeing climate change happen despite the fact that only half of fossil fuel emissions stay in the atmosphere while the other half is drawn down by the land biosphere and oceans,” Alden said. “If natural sinks saturate as models predict, the impact of human emissions on atmospheric CO2 will double.”
Ballantyne said recent studies by others have suggested carbon sinks were declining in some areas of the globe, including parts of the Southern Hemisphere and portions of the world’s oceans. But the new Nature study showed global CO2 uptake by Earth’s sinks essentially doubled from 1960 to 2010, although increased variations from year-to-year and decade-to-decade suggests some instability in the global carbon cycle, he said.
White, who directs CU-Boulder’s Institute of Arctic and Alpine Research, likened the increased pumping of CO2 into the atmosphere to a car going full throttle. “The faster we go, the more our car starts to shake and rattle,” he said. “If we drive 100 miles per hour, it is going to shake and rattle a lot more because there is a lot more instability, so it’s probably time to back off the accelerator,” he said. “The same is true with CO2 emissions.”
The atmospheric CO2 levels were measured at 40 remote sites around the world by researchers from NOAA and the Scripps Institution of Oceanography in La Jolla, Calif., including stations at the South Pole and on the Mauna Loa Volcano in Hawaii.
Carbon dioxide is emitted into the atmosphere primarily by fossil fuel combustion and by forest fires and some natural processes, said Ballantyne. “When carbon sinks become carbon sources, it will be a very critical time for Earth,” said Ballantyne. “We don’t see any evidence of that yet, but it’s certainly something we should be looking for.”
“It is important to understand that CO2 sinks are not really sinks in the sense that the extra carbon is still present in Earth’s vegetation, soils and the ocean,” said NOAA’s Tans. “It hasn’t disappeared. What we really are seeing is a global carbon system that has been pushed out of equilibrium by the human burning of fossil fuels.”
Despite the enormous uptake of carbon by the planet, CO2 in the atmosphere has climbed from about 280 parts per million just prior to the Industrial Revolution to about 394 parts per million today, and the rate of increase is speeding up. The global average of atmospheric CO2 is expected to reach 400 ppm by 2016, according to scientists.
The team used several global CO2 emissions reports for the Nature study, including one by the U.S. Department of Energy’s Carbon Dioxide Information Analysis Center. They concluded that about 350 billion tons of carbon -- the equivalent of roughly 1 trillion tons of CO2 -- had been emitted as a result of fossil fuel burning and land use changes from 1959 to 2010, with just over half moving into sinks on land or in the oceans.
According to the study, the scientists observed decreased CO2 uptake by Earth’s land and oceans in the 1990s, followed by increased CO2 sequestering by the planet from 2000 to 2010. “Seeing such variation from decade to decade tells us that we need to observe Earth’s carbon cycle for significantly longer periods in order to help us understand what is occurring,” said Ballantyne.
Scientists also are concerned about the increasing uptake of CO2 by the world’s oceans, which is making them more acidic. Dissolved CO2 changes seawater chemistry by forming carbonic acid that is known to damage coral, the fundamental structure of coral reef ecosystems that harbor 25 percent of the world’s fish species.
The study was funded by the National Research Council, the National Science Foundation and NOAA.
A total of 33.6 billion tons of CO2 were emitted globally in 2010, climbing to 34.8 billion tons in 2011, according to the International Energy Agency. Federal budget cuts to U.S. carbon cycle research are making it more difficult to measure and understand both natural and human influences on the carbon cycle, according to the research team.
“The good news is that today, nature is helping us out,” said White also a professor in CU’s geological sciences department. “The bad news is that none of us think nature is going to keep helping us out indefinitely. When the time comes that these carbon sinks are no longer taking up carbon, there is going to be a big price to pay.”
Ashley Ballantyne, 760-846-1391
Jim White, 303-492-5494