Cooperative Institute for Research in Environmental Sciences

When scientists from the Cooperative Institute for Research in Environmental Sciences (CIRES) and NOAA began routinely monitoring the atmosphere’s composition at a tower north of Denver a few years ago, their instruments immediately sniffed something strange: plumes of air rich with chemical pollutants, including the potent greenhouse gas methane.
Some of the pollutants picked up are known to damage air quality. Another, methane, is 25 times more effective per molecule than carbon dioxide at trapping heat in the atmosphere. The scientists were concerned. None of NOAA’s other air composition monitoring towers – there are eight, in total, scattered around the continental United States – had recorded anything similar.
"So we set out to understand where these chemicals were coming from, by starting at the tower measurements 1,000 feet high up, down to the ground in a mobile laboratory," said Gabrielle Petron, Ph.D., an atmospheric scientist at the Cooperative Institute for Research in Environmental Sciences (CIRES) and NOAA’s Earth System Research Laboratory (ESRL). Petron and co-workers customized air sampling devices and atmospheric chemistry instruments and headed out to northeastern Colorado, downwind of possible sources to collect chemical “fingerprints” that would help identify the possible sources.
After taking dozens of samples and thousands of readings along rural roads, near oil and gas equipment, landfills and animal feeding operations, the research team has an answer: The unusual air pollutants seen at the Denver tower came primarily from oil and gas production in northeastern Colorado’s Weld County.
"We found gas operations in the region leaked about twice as much methane into the atmosphere as previously estimated," Petron said. "And the oil and gas infrastructure was leaking other air pollutants, too, including benzene, which is regulated because of its toxicity."

Petron is lead author in a paper published online in the Journal of Geophysical Research this week.

In 2008, the year most of the data were collected, Weld County had nearly 14,000 operating oil and gas wells.

The research team’s chemical fingerprinting work showed that oil and gas equipment and the associated activities on well pads  –condensate storage tanks, pipelines, compressors and more – leaked or vented an estimated 4 percent of all natural gas produced to the atmosphere. That loss is about double the previous best-guess estimate, based on engineering calculations and industry data, of about 2 percent loss.

"We may have been significantly underestimating methane emissions by this industry in this region," Petron said. 
The team also found that emissions of benzene, a known carcinogen, are underestimated. Benzene is tracked and regulated by the Environmental Protection Agency (EPA). 
Petron and her colleagues found evidence of at least two sources of benzene in the region: oil and gas operations and something else, most likely cars and trucks on roads. And the new study found benzene emissions from oil and gas operations in the region to be significantly higher than expected, between 385 and 2,055 metric tons in 2008, compared with earlier estimates ranging from about 60 to 145 per year.

Finally, the researchers' findings suggest that oil and gas-related emissions of more reactive volatile organic compounds, which contribute to lung-damaging ozone pollution, are also underestimated. More reactive VOCs were not directly measured in the 2008 study, but are almost certainly co-emitted with methane and larger alkanes. According to the EPA, the northern Front Range has been out of compliance with federal health-based standards in the summer since 2007.

Chemist Greg Frost, Ph.D., also with CIRES and NOAA and a co-author of the new study, said the work demonstrates the value of studying emissions from several perspectives. Top-down studies (such as from the tall tower) can complement and verify bottom-up approaches (such as estimates based on average leak rates at pipe junctions). 

"What Gabrielle has done is to use the mobile laboratory and tower data to make top-down estimates of emissions, which can be used to evaluate the bottom-up estimates from industry and regulatory agencies,” Frost said. “This is going to inspire a lot more research."

Gabrielle Petron, CIRES,, 303-497-4890
Gregory Frost, CIRES,, 303-497-7539 
Katy Human, CIRES,, 303-735-0196

The exhaust fumes from gasoline vehicles contribute more to the production of a specific type of air pollution-secondary organic aerosols (SOA)-than those from diesel vehicles, according to a new study by scientists from the Cooperative Institute for Research in Environmental Sciences (CIRES), NOAA's Earth System Research Laboratory (ESRL) and other colleagues.

"The surprising result we found was that it wasn't diesel engines that were contributing the most to the organic aerosols in LA," said CIRES research scientist Roya Bahreini who led the study and also works at NOAA's ESRL. "This was contrary to what the scientific community expected."

SOAs are tiny particles that are formed in air and make up typically 40-60 percent of the aerosol mass in urban environments. This is important because fine-particle pollution can cause human health effects, such as heart or respiratory problems.

Due to the harmful nature of these particles and the fact that they can also impact the climate and can reduce visibility, scientists want to understand how they form, Bahreini said. Researchers had already established that SOAs could be formed from gases released by gasoline engines, diesel engines, and natural sources-biogenic agents from plants and trees-but they had not determined which of these sources were the most important, she said. "We needed to do the study in a location where we could separate the contribution from vehicles from that of natural emissions from vegetation," Bahreini said.

Los Angeles proved to be an ideal location. Flanked by an ocean on one side and by mountains to the north and the east, it is, in terms of air circulation, relatively isolated, Bahreini said. At this location, the scientists made three weekday and three weekend flights with the NOAA P3 research aircraft, which hosted an arsenal of instruments designed to measure different aspects of air pollution. "Each instrument tells a story about one piece of the puzzle," she said. "Where do the particles come from? How are they different from weekday to weekend, and are the sources of vehicle emissions different from weekday to weekend?" she said.

From their measurements, the scientists were able to confirm, as expected, that diesel trucks were used less during weekends, while the use of gasoline vehicles remained nearly constant throughout the week. The team then expected that the weekend levels of SOAs would take a dive from their weekday levels, Bahreini said.

But that was not what they found.

Instead the levels of the SOA particles remained relatively unchanged from their weekday levels. Because the scientists knew that the only two sources for SOA production in this location were gasoline and diesel fumes, the study's result pointed directly to gasoline as the key source.

"The contribution of diesel to SOA is almost negligible," Bahreini said. "Even being conservative, we could deduce from our results that the maximum upper limit of contribution to SOA would be 20 percent."

That leaves gasoline contributing the other 80 percent or more of the SOA, Bahreini said. The finding was published online March 1 in Geophysical Research Letters. "While diesel engines emit other pollutants such as soot and nitrogen oxides, for organic aerosol pollution they are not the primary culprit," Bahreini said.

If the scientists were to apply their findings from the LA study to the rest of the world, a decrease in the emission of organic species from gasoline engines may significantly reduce SOA concentrations on a global scale as well. This suggests future research aimed at understanding ways to reduce gasoline emissions would be valuable.

The study was funded by the National Oceanic and Atmospheric Administration's Climate Change and Air Quality Programs, the California Air Resources Board and The National Science Foundation.

CIRES coauthors on the team include Joost de Gouw, Carsten Warneke, Harald Stark, William Dube, Jessica Gilman, Katherine Hall, John Holloway, Anne Perring, Joshua Schwarz, Ryan Spackman, and Nicholas Wagner.

Roya Bahreini, CIRES,, 303-497-4804
Katy Human, CIRES,, 303-735-0196

Like snow sliding off a roof on a sunny day, the Greenland Ice Sheet may be sliding faster into the ocean due to massive releases of meltwater from surface lakes, according to a new study from the Cooperative Institute for Research in Environmental Sciences (CIRES) and the University of Colorado Boulder (CU). Such lake drainages may affect sea-level rise, with implications for coastal communities.

“This is the first evidence that Greenland’s supraglacial lakes have responded to recent increases in surface meltwater production by draining more frequently, as opposed to growing in size,” says CIRES research associate William Colgan, who co-led the study with CU’s Yu-Li Liang. The results were published online April 12 in Remote Sensing of Environment and will appear in the journal’s August issue.

During the summer, meltwater pools into lakes on the ice sheet’s surface. When the water pressure gets high enough, the ice fractures beneath the lake, forming a vertical drainpipe, and “a huge burst of water quickly pulses through to the bed of the ice sheet,” Colgan says.

The researchers used satellite images, along with innovative feature-recognition software, to monitor nearly 1,000 lakes on a Connecticut-sized portion of the ice sheet over a 10-year period. They discovered that as the climate warms, such catastrophic lake drainages are increasing in frequency. Catastrophic lake drainages were 3.5 times more likely to occur during the warmest years than the coldest.

During a typical catastrophic lake drainage, about 10 million cubic meters of meltwater—equivalent to 4,000 Olympic swimming pools—funnels to the ice sheet’s underside within a day or two. Once the water reaches the ice sheet’s belly, it may turn the ice-bed surface into a Slip ‘n Slide, lubricating the ice sheet’s glide into the ocean. This would accelerate the sea-level rise associated with climate change.

Alternatively, however, the lake drainages may carve out subglacial “sewers” to efficiently route water to the ocean. “This would drain the ice sheet’s water, making less water available for ice-sheet sliding,” Colgan says. That would slow the ice sheet’s migration into the ocean and decelerate sea-level rise.

“Lake drainages are a wild card in terms of whether they enhance or decrease the ice sheet’s slide,” Colgan says. Finding out which scenario is correct is a pressing question for climate models and for communities preparing for sea-level change, he added.

For the study, the researchers developed new feature-recognition software capable of identifying supraglacial lakes in satellite images and determining their size and when they appear and disappear. “Previously, much of this had to be double-checked manually,” Colgan says. “Now we feed the images into the code, and the program can recognize whether a feature is a lake or not, with high confidence and no manual intervention.”

Liang explains further: “Unlike the traditional methods that consider only physical properties of supraglacial lakes, our computer model also takes the temporal variation of lakes into account,” she says. “That is why the algorithm could successfully identify features in noisy and cloudy satellite images.”

Automating the process was vital since the study looked at more than 9,000 images. The researchers verified the program’s accuracy by manually looking at about 30 percent of the images over 30 percent of the study area. They found that the algorithm correctly detected and tracked 99 percent of supraglacial lakes.

The program could be useful in future studies to determine how lake drainages affect sea-level rise, Colgan said.

Coauthors on the team include Qin Lv, Konrad Steffen, Waleed Abdalati, Julienne Stroeve, David Gallaher, and Nicolas Bayou.

The study was funded by a grant from the Arctic Sciences Program of the US National Science Foundation to Stroeve, Gallaher, and Lv.

Yu-Li Liang,
William Coglan,, 303-735-3681 
Karin Vergoth, CIRES,, 303-497-5125

Scientists from CIRES and the University of Colorado Boulder have developed a new monitoring system to analyze and compare emissions from man-made fossil fuels and trace gases in the atmosphere, a technique that likely could be used to monitor the effectiveness of measures regulating greenhouse gases.

The research team looked at atmospheric gas measurements taken every two weeks from aircraft over a six-year period over the northeast United States to collect samples of CO2 and other environmentally important gases. Their method allowed them to separate CO2 derived from fossil fuels from CO2 being emitted by biological sources like plant respiration, said CU Boulder Senior Research Associate Scott Lehman, who led the study with CIRES scientist John Miller. 

The separation was made possible by the fact that CO2 released from the burning of fossil fuels like coal, oil and gas has no carbon-14, since the half-life of that carbon radio isotope is about 5,700 years -- far less than the age of fossil fuels, which are millions of years old. In contrast, CO2 emitted from biological sources on Earth like plants is relatively rich in carbon-14 and the difference can be pinpointed by atmospheric scientists, said Lehman. 

The team also measured concentrations of 22 other atmospheric gases tied to human activities as part of the study, said Miller. The diverse set of gases impact climate change, air quality and the recovery of the ozone layer, but their emissions are poorly understood. The authors used the ratio between the concentration level of each gas in the atmosphere and that of fossil fuel-derived CO2 to estimate the emission rates of the individual gases, said Miller. 

In the long run, measuring carbon-14 in the atmosphere offers the possibility to directly measure country and state emissions of fossil fuel CO2, said Miller. The technique would be an improvement over traditional, "accounting-based" methods of estimating emission rates of CO2 and other gases, which generally rely on reports from particular countries or regions regarding the use of coal, oil and natural gas, he said. 

"While the accounting-based approach is probably accurate at global scales, the uncertainties rise for smaller-scale regions," said Miller, also a scientist at the National Oceanic and Atmospheric Administration's Earth System Research Laboratory in Boulder. "And as CO2 emissions targets become more widespread, there may be a greater temptation to underreport. But we'll be able to see through that."

A paper on the subject was published in the April 19 issue of the Journal of Geophysical Research: Atmospheres, published by the American Geophysical Union. Co-authors include Stephen Montzka, Ed Dlugokencky, Colm Sweeney, Benjamin Miller, Anna Karion, Jocelyn Turnbull and Pieter Tans of CIRES, Chad Wolak of CU's INSTAAR and John Southton of the University of California, Irvine.
One surprise in the study was that the researchers detected continued emissions of methyl chloroform and several other gases banned from production in the United States. Such observations emphasize the importance of independent monitoring, since the detection of such emissions could be overlooked by the widely used accounting-based estimation techniques, said CIRES Fellow Montzka. 

The atmospheric air samples were taken every two weeks for six years by aircraft off the coastlines of Cape May, N.J., and Portsmouth, N.H. 

Fossil fuel emissions have driven Earth's atmospheric CO2 from concentrations of about 280 parts per million in the early 1800s to about 390 parts per million today, said Miller. The vast majority of climate scientists believe higher concentrations of the greenhouse gas CO2 in Earth's atmosphere are directly leading to rising temperatures on the planet. 

"We think the approach offered by this study can increase the accuracy of emissions detection and verification for fossil fuel combustion and a host of other man-made gases," said Lehman. He said the approach of using carbon-14 has been supported by the National Academy of Sciences and could be an invaluable tool for monitoring greenhouse gases by federal agencies like NOAA. 

Unfortunately, NOAA's greenhouse gas monitoring program has been cut back by Congress in recent years, said Lehman. "Even if we lack the will to regulate emissions, the public has a right to know what is happening to our atmosphere. Sticking our heads in the sand is not a sound strategy," he said. 

John Miller, 303-497-7739, 
Karin Vergoth, CIRES, 303-497-5125,

A smoke-related chemical, isocyanic acid, may be a significant air pollutant in some parts of the world, especially where forest fires and other forms of biomass burning are common, according to new research by Cooperative Institute for Research in Environmental Sciences (CIRES) scientists and colleagues.

In a modeling study, the scientists found that relatively high levels of isocyanic acid likely occur in parts of tropical Africa, Southeast Asia, China, Siberia, and the Western Amazon Basin.

“This is the first study to model the global distribution of isocyanic acid, and the concentrations we estimated for many regions are high enough to warrant more research to understand people’s exposures,” said CIRES scientist Paul Young Paul Young, lead author of the paper published online April 30 in the Journal of Geophysical Research. Young is also an atmospheric scientist with NOAA’s Earth System Research Laboratory.

Isocyanic acid is emitted by burning biomass including forest fires, and inefficient wood-burning stoves. In the body, isocyanic acid can trigger certain kinds of protein damage which, in turn, leads to cataracts and inflammation associated with cardiovascular disease and rheumatoid arthritis, according to published health research.

CIRES scientists published a study last year that was one of the first to observe the acid in the air. Using a CIRES-NOAA custom-built instrument, the researchers found the chemical in the air of downtown Los Angeles, downwind of a Colorado wildfire, and in cigarette smoke. That study also suggested that if the acid was present in the air at 1 part per billion by volume (ppbv) or higher, it could trigger chemical reactions associated with negative health effects.

In the new study, Young and his colleagues investigated further, using a sophisticated computer model of the atmosphere to better understand the chemical’s distribution around the globe. Their model used the limited information available on isocyanic acid to include processes that remove the chemical from the atmosphere and to estimate its emissions.

The researchers found that annual average levels of isocyanic acid are likely highest in parts of China, where modeled concentrations reached 0.470 ppbv (about half of the 1 ppbv suspected to trigger health concerns). But at certain times, the pollutant spiked significantly higher in regions where episodic fires occurred: Isocyanic levels periodically reached 4 ppbv in parts of tropical Africa and the Western Amazon Basin, and up to 10 ppbv in southeast Asia and Siberia.

In parts of Siberia and tropical Africa, modeled isocyanic acid levels surpassed 1 ppbv for more than 60 days out of the year, the team reported. In more highly populated areas, however, exposure is potentially more significant: For Southeast Asia, the scientists estimated that more than 50 million people could be exposed to levels of isocyanic acid above 1 ppbv for more than seven days in one year.  

Isocyanic acid is difficult to detect in the atmosphere with conventional measurement techniques, and the emissions estimates in the new paper are likely significantly underestimated in some parts of the world (where inefficient stoves are common), and possibly overestimated in others (where fossil fuel burning for electricity is more common).

“Our estimates are preliminary,” said co-author Jim Roberts, a NOAA chemist. “But given the potentially high concentrations of isocyanic acid in those hotspots, and the numbers of people potentially affected, we hope that more atmospheric scientists and health researchers will be encouraged to look into this issue.”

Karin Vergoth, CIRES,, 303-497-5125

Starting today, a sophisticated new weather forecast computer model developed by scientists from the Cooperative Institute for Research in Environmental Sciences (CIRES) and NOAA will help improve predictions of quickly developing severe weather events such as thunderstorms, winter storms and dangerous air turbulence.

The Rapid Refresh model was developed at NOAA’s Earth System Research Laboratory (ESRL) in Boulder, Colo. in collaboration with NOAA’s National Centers for Environmental Prediction (NCEP) in Camp Springs, Md. It provides NOAA’s most rapidly updated weather forecast, updating every hour with a new forecast extending out 18-hours for North America. Such forecasts are especially important in aviation, where fast-developing weather conditions can affect safety and efficiency, but they are also important for severe weather and energy-related forecasting.

“When accurate and timely weather modeling is needed most, the new Rapid Refresh model delivers,” said Louis Uccellini, Ph.D., director, NOAA’s National Centers for Environmental Prediction, a part of NOAA’s National Weather Service. “This new tool ensures that forecasts are the best they can be by using the latest science and computer techniques in effort to create a more weather-ready nation.”

The United States is the only country in the world that updates computer model forecasts every hour using the latest observations from an extensive network of ground- and satellite-based sensors, radars and aircraft, said CIRES Fellow Stan Benjamin, lead developer of the new model and a research meteorologist at ESRL.

The new model was tested extensively, running experimentally for 22 months at NOAA’s NCEP, and will replace the older rapidly updated model, Rapid Update Cycle (RUC). In comparisons with that older model, the new Rapid Refresh (RAP) performed well. “Overall, RAP provides equal or better forecasts than RUC for all variables, from winds to precipitation,” Benjamin said.

For example, RAP performed significantly better than its predecessor in forecasting heavy rain that pounded the Midwest in June last year. For one 24-hour period of comparison, RAPs forecasts correctly projected more of the regions that received 2 inches or more of precipitation.

RAP’s skillful forecasts derive from three key improvements over the earlier model: RAP is based on a significantly more advanced numerical weather prediction model, the Weather Research and Forecasting (WRF) model. WRF was created through a collaboration of NOAA, the National Center for Atmospheric Research, the Air Force Weather Agency, and dozens of other research institutions; RAP uses an innovative technique for “assimilating” current observations used to start the forecast model. The newer assimilation technique, developed through a NOAA-NASA research partnership led by NOAA’s NCEP, improves short-range forecasts; and RAP extends the geographical coverage of NOAA’s weather situational awareness information to all of North America, not just the contiguous U.S. as was the case for the RUC model.

The addition of Alaska, where air travel is common, is particularly important. “The majority of Alaska is not connected to a road network, so the only means of transportation to many locations is by air,” said Gene Petrescu, science and technology transfer meteorologist at NOAA’s National Weather Service in Anchorage, Alaska. “We are hearing from our forecast offices that they see value in these hourly forecasts.”

CIRES scientists instrumental in developing the model along with Stan Benjamin are Curtis Alexander, Ming Hu, Tanya Smirnova, Joe Olson, Patrick Hofmann, Eric James, Bill Moninger, Xue Wei, Steven Peckham Media Contact: Karin Vergoth,, 303-497-5125

The uncovering of a new type of wave may have a ripple effect in the Earth and planetary sciences, says the scientist from the Cooperative Institute for Research in Environmental Sciences (CIRES) who discovered the wave.

“It is completely unexpected—the wave type is unusual in several respects,” said CIRES Senior Research Scientist Oleg Godin, whose finding was published May 9 in Physical Review Letters. “It just flies in the face of what we teach students.”

Both in water and air, waves can vary in height—amplitude—and in length—wavelength.  These waves, which can range from less than a centimeter in length to thousands of kilometers, play a key role in transferring energy both within and between the ocean and the atmosphere. “In this way, to a large degree waves control weather and climate,” Godin said.

Previously, while a collection of mathematical solutions have explained the impact of variables such as a fluid’s buoyancy and compressibility on how waves move through fluids, they don’t fully describe the diversity of the wave types. The new wave, with its simple and exact mathematical description, will grant scientists greater understanding of how waves transfer energy through the environment and the subsequent climatic implications. 

“The discovery has uncovered a new mechanism of coupling between physical processes in the ocean and the atmosphere,” Godin said. “The new wave gives us an opportunity to really understand some aspects of what is going on.”

The new wave type comes with some unique quirks, Godin said. While the wave can move through fluid at speeds close to, or greater than, the speed of sound, motion does not compress the fluid. Another unusual characteristic is that the vertical structure of the fluid motion is independent of sound speed and density variation in the fluid, he said.

This latter anomaly is one that may have implications for remote sensing, Godin said. It means the wave type is highly sensitive to background fluid velocity (such as wind velocity), and specific measurements taken of the new wave type can reveal a full wind profile without having to obtain knowledge of other properties such as the temperature field and other material parameters.

“This is particularly important for remote sensing of atmospheres on other planets, where we do not have a lot of information about their material properties,” Godin said. 

Given there are very few tools to study large-scale motion in the atmospheres of planets, the new wave type may prove a valuable asset to scientists, he said. “It allows you to probe different aspects of the atmosphere,” he said.  

Oleg Godin, CIRES,, 303-497-6558
Karin Vergoth, CIRES,, 303-497-5125

Thinning sea ice in spring affects ozone chemistry, with implications for mercury contamination

Arctic warming has thinned the blanket of sea ice that stretches across the Arctic Ocean in springtime and a study led by a scientist from the Cooperative Institute for Research in Environmental Sciences (CIRES) shows that this change is altering the chemistry of the atmosphere at ground level in the region. Those atmospheric changes may, in turn, be increasing the amount of toxic mercury contaminating the region.

“We have observed a substantial increase in springtime surface ozone-depletion events in the Arctic during the last 40 years,” said Samuel Oltmans, lead author of a new study published in the Journal of Geophysical Research. “We haven’t been measuring mercury long enough to know yet if mercury deposition, itself, is getting worse, but that is likely.”
The sea ice and mercury changes are linked chemically through bromine, which is released from seawater. The sea ice surface controls the way bromine escapes the ocean and reaches the atmosphere. When they do reach the air, bromine molecules can do two things: chemically scrub out ozone, and transform mercury from a fairly unreactive form to a reactive form. Reactive mercury can fall out of the atmosphere into snow, ice and the ocean.

“It is this converted form of mercury that can be incorporated into Arctic food chains in the ocean and on land,” said Oltmans, an atmospheric scientist with CIRES and NOAA’s Earth System Research Laboratory.  At high enough levels, mercury can harm organisms’ nerves, brains, reproductive systems and more, depending on the form of the metal and type of exposure.

Oltmans detailed the relationship between sea ice, ozone and mercury this week during the Global Monitoring Annual Conference at NOAA’s Earth System Research Laboratory in Boulder, Colo.

Scientists have long known that the chemical bromine can escape seawater and get into the atmosphere, where it can trigger reactions that destroy ground-level ozone, which is both a naturally coccurring component of the atmosphere and a pollutant. High levels of ozone can damage people’s lungs and plants, so in general, less ozone is good for air quality.

But in the Arctic, there’s a catch: when surface ozone-scrubbing events occur, changes in the atmosphere also transform airborne mercury into its more reactive form. It is well-known that when atmospheric mercury is transformed into reactive form, much of it disappears from the atmosphere and accumulates in the snow and ice below.

Recently, other scientists have shown that thin ”annual” sea ice (ice that formed during the previous winter and is riddled with cracks) is better at promoting bromine-related ozone destruction than thick, sturdy multi-year ice. Springtime sea ice in the Arctic is much thinner than it was in the past, with far less multi-year ice.

In the new study, Oltmans and his colleagues pull the story together, showing that ground-level ozone-depletion events are significantly more common during the month of March in recent years than they were just a few decades years ago.
“In the first half of the record, ozone depletion events were rare, occurring less than 15 percent of the time in March,” Oltmans said. But since 1993, ozone depletion events have occurred more than 25 percent of the time.

He and his colleagues showed that the increase in ozone-scrubbing events is not related to changes in wind patterns in the Arctic; rather, it appears that the thinner ice is promoting the changes in chemistry.

And that, Oltmans suspects, is bad news for Arctic ecosystems already well-known to suffer from mercury contamination. If warming continues, leading to more ozone-depletion events, that may well also mean that mercury is slipping more easily into Arctic food webs.

“In addition to measuring ozone, we will also want to routinely track mercury levels,” Oltmans said, “since it is the mercury compounds that have the most direct environmental implications for the Arctic.”

Sam Oltmans, CIRES,, 720-442-5794
Karin Vergoth, CIRES,, 303-497-5125

A decline in the population of emperor penguins appears likely this century as climate change reduces the extent of Antarctic sea ice, according to a detailed projection published this week.

The study, led by the Woods Hole Oceanographic Institution (WHOI), with co-authors from the CIRES, the National Center for Atmospheric Research (NCAR) and other organizations, focuses on a much-observed colony of emperor penguins in Terre Adélie, Antarctica. The authors conclude that the number of breeding pairs may fall by about 80 percent by 2100.

“The projected decreases in sea ice may fundamentally alter the Antarctic environment in ways that threaten this population of penguins,” says NCAR scientist Marika Holland, a co-author of the study.

The study uses a set of sophistical computer simulations of climate as well as a statistical model of penguin demographics. Building on previous work, it examines how the sea ice may vary at key times during the year such as during egg laying, incubation, rearing chicks, and non- breeding season, as well as the potential influence of sea ice concentrations on males and females.

The authors stress that their projections contain large uncertainties, because of the difficulties in projecting both climate change and the response of penguins. However, almost all of their computer simulations pointed to a significant decline in the colony at Terre Adélie, a coastal region of Antarctica where French scientists have conducted penguin observations for more than 50 years.
“Our best projections show roughly 500 to 600 breeding pairs remaining by the year 2100,” says lead author Stéphanie Jenouvrier, a WHOI biologist. “Today, the population size is around 3,000 breeding pairs.”

She noted that another penguin population, the Dion Islets penguin colony close to the West Antarctic Peninsula, has disappeared, possibly because of a decline in Antarctic sea ice.

The new research represents a major collaboration between biologists and climate scientists to assess the potential impacts of climate change on a much-studied species.

Published this week in the journal Global Change Biology, the study was funded in part by the National Science Foundation, NCAR’s sponsor. Other funders include WHOI; the French National Agency for Research (ANR) program on biodiversity; the ANR REMIGE program (Behavioral and Demographic Responses of Indian Ocean Marine Top Predators to Global Environmental Changes); the Zone Research Workshop for the Antarctic and Subantarctic Environment (ZATA); the Paul Emilie Victor Institute (IPEV); Alexander von Humboldt Foundation; Marie-Curie European Fellowship; and the U.S. Cooperative Institute for Research in Environmental Sciences (CIRES) visiting fellowship.

Vulnerable emperors of the ice

At nearly four feet tall, emperors are the largest species of penguin. They are vulnerable to changes in sea ice, where they breed and raise their young almost exclusively. If that ice breaks up and disappears early in the breeding season, massive breeding failure may occur, Jenouvrier says.

Disappearing sea ice may also affect the penguins’ food sources. They feed primarily on fish, squid, and krill, a shrimplike animal that feeds on zooplankton and phytoplankton that grow on the underside of ice. If the ice goes, Jenouvrier says, so too will the plankton, causing a ripple effect through the food web that may starve the various species that penguins rely on as prey.

To project how the extent of sea ice in the region will change this century, Holland and another co-author, Julienne Stroeve, a sea ice specialist from CIRES National Snow and Ice Data Center.(NSIDC), evaluated 20 of the world’s leading computer-based climate models. They selected the five models that most closely reproduced changes in actual Antarctic sea ice cover during the 20th century.
“When a computer simulation performs well in reproducing past climate conditions, that suggests its projections of future climate conditions are more reliable,” Holland says.

The team evaluated simulations from each of the 20 climate models. The simulations were based on a scenario of moderate growth in greenhouse gas emissions during this century. The moderate growth scenario portrays future reliance by society on a combination of greenhouse-gas emitting fossil fuels as well as renewable energy sources.

The simulations showed a decline in sea ice coverage across a large region by Terre Adélie at key times in the penguin breeding cycle, although they differed in the details.

Jenouvrier used the output from the climate models to determine how changes in temperature and sea ice might affect the emperor penguin population at Terre Adélie, studying such details as how the sea ice was likely to vary during breeding season and how it could affect chicks, breeding pairs, and non-breeding adults. She found that if global temperatures continue to rise at their current rate—causing sea ice in the region to shrink—penguin population numbers most likely will diminish slowly until about 2040, after which they would decline at a much steeper rate as sea ice coverage drops below a usable threshold.

The authors say that more research is needed to determine whether emperor penguins may be able to adapt to changing conditions or disperse to regions where the sea ice is more habitable.

Human reliance on the Antarctic

Rising temperature in the Antarctic isn’t just a penguin problem, according to Hal Caswell, a senior mathematical biologist at WHOI and collaborator on the study. As sea ice coverage continues to shrink, the resulting changes in the Antarctic marine environment will affect other species, and may affect humans as well.

“We rely on the functioning of those ecosystems,” he says. “We eat fish that come from the Antarctic. We rely on nutrient cycles that involve species in the oceans all over the world. Understanding the effects of climate change on predators at the top of marine food chains—like emperor penguins—is in our best interest, because it helps us understand ecosystems that provide important services to us."

CIRES co-authors of the study were Mark Serreze and Julienne Stroeve of the National Snow and Ice Data Center in the United States.

About the article

Title: Effects of climate change on an emperor penguin population: analysis of coupled demographic and climate models

Authors:  Stéphanie Jenouvrier, Marika Holland, Julienne Stroeve, Christophe Barbraud, Henri Weimerskirch, Mark Serreze, and Hal Caswell

Journal: Global Change Biology

Press release courtesy of NCAR/UCAR Communications

The White House today named CIRES scientists David Noone and Rebecca Washenfelder as recipients of the 2011 Presidential Early Career Award for Scientists and Engineers (PECASE). The PECASE award is the highest honor given by the U.S. government to outstanding scientists and engineers in the early stages of their careers.

Noone’s award citation acknowledges him for his “innovative use of stable isotope tracers and modeling efforts directed towards an integrated understanding of the cycling of water and carbon dioxide through the atmosphere, and for actively engaging students in cutting-edge research at middle schools.”

“The award is a fabulous honor,” Noone said. “It is a tremendous recognition that I’m delighted to share with the wonderful students and colleagues with whom I work, and it is truly humbling.”
Currently, Noone, a CIRES Fellow, is working with nearly 200 school children to collect rainwater that falls on rooftops. His team then analyzes the samples’ water chemistry to determine where the water came from and eventually what its fate will be. The rainfall data being collected complement other measurements that he makes using advanced laser spectrometers, and together, they provide a critical body of information that is essential for advancing state-of-the-art climate models.

“Water is so pervasive in so many aspects of our environment, but it remains a challenge to understand both how changing climate will alter the water cycle and how changes in the water cycle influence climate,” Noone said.

“Understanding how water moves around in the air and on the land surface—the water cycle—will help us know how to use water more effectively for agriculture, environmental sustainability, and recreation and also improve estimates of regional climate change,” Noone said. “This project is not really possible without combining citizen science—in this case, the help of students—with the work my group is doing in CIRES.”

Noone, who has given talks both in schools and in the local community about his research, sees combining climate research with outreach work as important for both raising awareness about important environmental issues and increasing interest in science. “I really enjoy science. I think it is really exciting, and I like to share that with people,” Noone said. “It is just a lot of great fun figuring out how the natural world works.” He also hopes that his enthusiasm for science will inspire middle-school students to consider careers in science.

An article about his research and involvement with education and outreach, “Science ‘n’ Schools Symbiosis,” will be coming out in the next edition of CIRES’s science magazine, Spheres (September 2012 edition). To see a presentation about his work, click here, and for a video about his work, click here.

Washenfelder’s award citation acknowledges her for her “pioneering work in developing and applying new measurement techniques to study atmospheric chemistry related to climate and air quality and for commitment to science education and outreach.” 

Washenfelder, an atmospheric chemist, developed a new instrument that uses light to measure the concentrations of trace pollutants in the atmosphere. She used this instrument during field measurements in Los Angeles, Calif., to study the sources and composition of aerosols—tiny airborne particles that can impact both air quality and climate. It is hoped that Washenfelder’s new instrument can be extended for field measurements of other atmospheric species as well.

Washenfelder has also been actively involved in education and outreach, working to communicate the importance and progress of her research to the public. To read an article on her research, work that has helped improve air quality in Houston, Texas, click here. To listen below to a podcast with Washenfelder:

Washenfelder, who earned her master’s and doctoral degrees in environmental science and engineering from the California Institute of Technology, says she first became interested in her chosen career while a student at Pomona College in Los Angeles County. As she ran around the college’s track, she says, she sometimes couldn’t even see the nearby San Gabriel Mountains because of the smog. “There would just be a brown haze and no mountains,” Washenfelder said. “I was fascinated by the air quality and decided that I wanted to study atmospheric chemistry.”

“I am honored to receive this award,” she said.

Both Washenfelder and Noone are faculty scientists with the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder; Noone also serves on the faculty of CU’s Department of Atmospheric and Oceanic Sciences. According to William Lewis, CIRES Interim Director, “these two outstanding young scientists are making discoveries of great fundamental and practical importance; they illustrate the great strength of environmental sciences at University of Colorado Boulder as developed through collaboration between CU’s institutes and departments.”

David Noone, CIRES Fellow,, 303-735-6073
Rebecca Washenfelder, CIRES scientist,, 303-497-4810 
Karin Vergoth, CIRES,, 303-497-5125

CIRES is a partnership of NOAA and CU Boulder.