Study shows a recent reversal in the response of western Greenland’s ice caps to climate change

Study shows a recent reversal in the response of western Greenland’s ice caps to climate change

Study Shows A Recent Reversal in the Response of Western Greenland’s Ice Caps to Climate Change

Sept 9, 2021
RENO, NV

Climate Change
Polar Research
Ice Cores

Above: A wide view of the Nuussuaq Peninsula in West Greenland. Project collaborators investigate an ice core extracted from this region for signs of change and response to past periods of warming.

Credit: Sarah Das © Woods Hole Oceanographic Institution

Research suggests some ice caps grew during past periods of warming

Although a warming climate is leading to rapid melting of the ice caps and glaciers along Greenland’s coastline, ice caps in this region sometimes grew during past periods of warming, according to new research published today in Nature Geoscience. The study team included Joseph McConnell, Nathan Chellman, and Monica Arienzo of DRI, who analyzed a 140 m ice core from an ice cap on Greenland’s Nuussuaq Peninsula at DRI’s Ice Core Laboratory in Reno, Nevada.

“The use of records from Greenland’s coastal ice caps in climate change research has been hampered by difficulties in creating chronologies for ice-core measurements,” said McConnell. “Here we used a novel approach based on synchronizing detailed measurements of heavy metals in an array of Greenland ice cores.”

“This allowed creation of a tightly constrained chronology in a coastal core for the first time, and it was this chronology that underpinned this climate study,” Chellman added.

The analysis was done using DRI’s unique continuous ice core analytical system, which was developed in McConnell’s lab and funded by grants from the National Science Foundation during the past 15 years.

The full news release from Woods Hole Oceanographic Institution is below.

Ice capped and snow-covered mountains of coastal west Greenland. (Apr. 2015)

Ice capped and snow-covered mountains of coastal west Greenland. (Apr. 2015)

Credit: Matthew Osman © Woods Hole Oceanographic Institution

Thumbnail image of nature geoscience paper

The full text of the study, “Abrupt Common Era hydroclimate shifts drive west Greenland ice cap change,” is available from Nature Geoscience: https://www.nature.com/articles/s41561-021-00818-w.pdf 

News release reposted from Woods Hole Oceanographic Institution:

Woods Hole, Mass. (September 9, 2021) – Greenland may be best known for its enormous continental scale ice sheet that soars up to 3,000 meters above sea level, whose rapid melting is a leading contributor to global sea level rise. But surrounding this massive ice sheet, which covers 79% of the world’s largest island, is Greenland’s rugged coastline dotted with ice capped mountainous peaks. These peripheral glaciers and ice caps are now also undergoing severe melting due to anthropogenic (human-caused) warming.  However, climate warming and the loss of these ice caps may not have always gone hand-in-hand.

New collaborative research from the Woods Hole Oceanographic Institution and five partner institutions (University of Arizona, University of Washington, Pennsylvania State University, Desert Research Institute and University of Bergen), published today in Nature Geoscience, reveals that during past periods glaciers and ice caps in coastal west Greenland experienced climate conditions much different than the interior of Greenland. Over the past 2,000 years, these ice caps endured periods of warming during which they grew larger rather than shrinking.

This novel study breaks down the climate history displayed in a core taken from an ice cap off Greenland’s western coast. According to the study’s researchers, while ice core drilling has been ongoing in Greenland since the mid-20th century, coastal ice core studies remain extremely limited, and these new findings are providing a new perspective on climate change compared to what scientists previously understood by using ice cores from the interior portions of the Greenland ice sheet alone.

“Glaciers and ice caps are unique high-resolution repositories of Earth’s climate history, and ice core analysis allows scientists to examine how environmental changes – like shifts in precipitation patterns and global warming – affect rates of snowfall, melting, and in turn influence ice cap growth and retreat,” said Sarah Das, Associate Scientist of Geology and Geophysics at WHOI. “Looking at differences in climate change recorded across several ice core records allows us to compare and contrast the climate history and ice response across different regions of the Arctic.” However, during the course of this study, it also became clear that many of these coastal ice caps are now melting so substantially that these incredible archives are in great peril of disappearing forever.

The research team on the ground of a coastal West Greenland ice cap, preparing to extract and examine ice cores.

The research team on the ground of a coastal West Greenland ice cap, preparing to extract and examine ice cores.

Credit: Sarah Das © Woods Hole Oceanographic Institution

Due to the challenging nature of studying and accessing these ice caps, this team was the first to do such work, centering their study, which began in 2015, around a core collected from the Nuussuaq Peninsula in Greenland. This single core offers insight into how coastal climate conditions and ice cap changes covaried during the last 2,000 years, due to tracked changes in its chemical composition and the amount of snowfall archived year after year in the core. Through their analysis, investigators found that during periods of past warming, ice caps were growing rather than melting, contradicting what we see in the present day. 

“Currently, we know Greenland’s ice caps are melting due to warming, further contributing to sea level rise. But, we have yet to explore how these ice caps have changed in the past due to changes in climate,” said Matthew Osman, postdoctoral research associate at the University of Arizona and a 2019 graduate of the MIT-WHOI Joint program. “The findings of this study were a surprise because we see that there is an ongoing shift in the fundamental response of these ice caps to climate: today, they’re disappearing, but in the past, within small degrees of warming, they actually tended to grow.” 

According to Das and Osman, this phenomenon happens because of a “tug-of-war” between what causes an ice cap to grow (increased precipitation) or recede (increased melting) during periods of warming. Today, scientists observe melting rates that are outpacing the rate of annual snowfall atop ice caps. However, in past centuries these ice caps would expand due to increased levels of precipitation brought about by warmer temperatures. The difference between the past and present is the severity of modern anthropogenic warming.

The team gathered this data by drilling through an ice cap on top of one of the higher peaks of the Nuussuaq Peninsula. The entire core, about 140 meters in length, took about a week to retrieve. They then brought the meter-long pieces of core to the National Science Foundation Ice Core Facility in Denver, Colorado, and stored at -20 degrees Celsius. The core pieces were then analyzed by their layers for melt features and trace chemistry at the Desert Research Institute in Reno, Nevada. By looking at different properties of the core’s chemical content, such as parts per billion of lead and sulfur, investigators were able to accurately date the core by combining these measurements with a model of past glacier flow.

“These model estimates of ice cap flow, coupled with the actual ages that we have from this high precision chemistry, help us outline changes in ice cap growth over time. This method provides a new way of understanding past ice cap changes and how that is correlated with climate,” said Das. “Because we’re collecting a climate record from the coast, we’re able to document for the first time that there were these large shifts in temperature, snowfall and melt over the last 2,000 years, showing much more variability than is observed in records from the interior of Greenland,” Das added. 

“Our findings should urge researchers to return to these remaining ice caps and collect new climate records while they still exist,” added Osman. 

University of Arizona postdoctoral research associate Matthew Osman and U.S. Ice Drilling Program specialist Mike Waszkiewicz move an ice core barrel into place in West Greenland, as part of their work to study ice caps’ response to climate change.

The research team on the ground of a coastal West Greenland ice cap, preparing to extract and examine ice cores.

Credit: Sarah Das © Woods Hole Oceanographic Institution

Additional collaborators and institutions:

  • Benjamin Smith, University of Washington
  • Luke Trusel, Pennsylvania State University
  • Joseph McConnell, Desert Research Institute
  • Nathan Chellman, Desert Research Institute
  • Monica Arienzo, Desert Research Institute
  • Harold Sodemann, University of Bergen and Bjerknes Centre for Climate Research 

This research is funded by the National Science Foundation (NSF), with further support from the U.S. Department of Defense National Defense Science and Engineering Graduate Fellowship; and an Ocean Outlook Fellowship to the Bjerknes Centre for Climate Research; the National Infrastructure for High Performance Computing and Data Storage in Norway; Norwegian Research Council; and Air Greenland. 

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About Woods Hole Oceanographic Institution

The Woods Hole Oceanographic Institution (WHOI) is a private, non-profit organization on Cape Cod, Massachusetts, dedicated to marine research, engineering, and higher education. Established in 1930, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate an understanding of the ocean’s role in the changing global environment. WHOI’s pioneering discoveries stem from an ideal combination of science and engineering—one that has made it one of the most trusted and technically advanced leaders in basic and applied ocean research and exploration anywhere. WHOI is known for its multidisciplinary approach, superior ship operations, and unparalleled deep-sea robotics capabilities. We play a leading role in ocean observation and operate the most extensive suite of data-gathering platforms in the world. Top scientists, engineers, and students collaborate on more than 800 concurrent projects worldwide—both above and below the waves—pushing the boundaries of knowledge and possibility. For more information, please visit www.whoi.edu

About DRI

The Desert Research Institute (DRI) is a recognized world leader in basic and applied environmental research. Committed to scientific excellence and integrity, DRI faculty, students who work alongside them, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge on topics ranging from humans’ impact on the environment to the environment’s impact on humans. DRI’s impactful science and inspiring solutions support Nevada’s diverse economy, provide science-based educational opportunities, and inform policymakers, business leaders, and community members. With campuses in Las Vegas and Reno, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu.

DRI Ice Core Lab Data Shows Magnitude of Historic Fire Activity in Southern Hemisphere

DRI Ice Core Lab Data Shows Magnitude of Historic Fire Activity in Southern Hemisphere

DRI Ice Core Lab Data Shows Magnitude of Historic Fire Activity in Southern Hemisphere

May 28, 2021
RENO, NEV.

Ice Cores
Fire Activity
Climate Change

Above: Smoke from human-caused wildfires on the Patagonian steppe are trapped in Antarctic ice. 

Credit: Kathy Kasic/Brett Kuxhausen, Montana State University.

A new study in Science Advances features ice core data from the DRI Ice Core Laboratory and research by Nathan Chellman, Ph.D., Monica Arienzo, Ph.D., and Joe McConnell, Ph.D.

Fire emissions in the Southern Hemisphere may have been much higher during pre-industrial times than in the present day, according to new research from an international team of scientists including Nathan Chellman, Ph.D., Monica Arienzo, Ph.D., and Joe McConnell, Ph.D., of the Desert Research Institute (DRI) in Reno.

The study, published today in Science Advances, used new ice core data from DRI’s Ice Core Laboratory to document changes in levels of soot from ancient fires and modern fossil fuel combustion during the years 1750 to 2000. Many of the 14 Antarctic ice cores included in the study were obtained through national and international collaborations, and together comprise an unprecedented long-term record of Southern Hemisphere fire activity that provided the foundation for the modeling effort described in the new paper.

All of the ice cores were analyzed using a specialized method for soot measurements in ice that McConnell and his team pioneered at DRI nearly 15 years ago. This method is now widely used in laboratories around the world.

For more information about the DRI Ice Core Laboratory, please visit: https://www.dri.edu/labs/trace-chemistry-laboratory/. The full news release from Harvard University, A fiery past sheds new light on the future of global climate change, is posted below.

Co-author Dr. Robert Mulvaney from the British Antarctic Arctic Survey drilling the James Ross Island core in the Antarctic Peninsula.

Co-author Dr. Robert Mulvaney from the British Antarctic Arctic Survey drilling the James Ross Island core in the Antarctic Peninsula. 

Credit: Robert Mulvaney.

Thumnail image of Science Advances paper, links to paper

The full text of the paper, Improved estimates of preindustrial biomass burning reduce the magnitude of aerosol climate forcing in the Southern Hemisphere, is available from Science Advances: https://advances.sciencemag.org/content/7/22/eabc1379.abstract

A fiery past sheds new light on the future of global climate change

Ice core samples reveal significant smoke aerosols in the pre-industrial Southern Hemisphere 

By Leah Burrows, Harvard University

Centuries-old smoke particles preserved in the ice reveal a fiery past in the Southern Hemisphere and shed new light on the future impacts of global climate change, according to new research published in Science Advances.

“Up till now, the magnitude of past fire activity, and thus the amount of smoke in the preindustrial atmosphere, has not been well characterized,” said Pengfei Liu, a former graduate student and postdoctoral fellow at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and first author of the paper. “These results have importance for understanding the evolution of climate change from the 1750s until today, and for predicting future climate.”

One of the biggest uncertainties when it comes to predicting the future impacts of climate change is how fast surface temperatures will rise in response to increases in greenhouse gases. Predicting these temperatures is complicated since it involves the calculation of competing warming and cooling effects in the atmosphere. Greenhouse gases trap heat and warm the planet’s surface while aerosol particles in the atmosphere from volcanoes, fires and other combustion cool the planet by blocking sunlight or seeding cloud cover. Understanding how sensitive surface temperature is to each of these effects and how they interact is critical to predicting the future impact of climate change.

Ancient ice from James Ross Island in the Northern Antarctic Peninsula about to be extracted from the drill barrel.

Ancient ice from James Ross Island in the Northern Antarctic Peninsula about to be extracted from the drill barrel. 

Credit: Robert Mulvaney.

Many of today’s climate models rely on past levels of greenhouse gasses and aerosols to validate their predictions for the future. But there’s a problem: While pre-industrial levels of greenhouse gasses are well documented, the amount of smoke aerosols in the preindustrial atmosphere is not. 

To model smoke in the pre-industrial Southern Hemisphere, the research team looked to Antarctica, where the ice trapped smoke particles emitted from fires in Australia, Africa and South America. Ice core scientists and co-authors of the study, Joseph McConnell and Nathan Chellman from the Desert Research Institute in Nevada, measured soot, a key component of smoke, deposited in an array of 14 ice cores from across the continent, many provided by international collaborators.

“Soot deposited in glacier ice directly reflects past atmospheric concentrations so well-dated ice cores provide the most reliable long-term records,” said McConnell.    

What they found was unexpected.

“While most studies have assumed less fire took place in the preindustrial era, the ice cores suggested a much fierier past, at least in the Southern Hemisphere,” said Loretta Mickley, Senior Research Fellow in Chemistry-Climate Interactions at SEAS and senior author of the paper.

To account for these levels of smoke, the researchers ran computer simulations that account for both wildfires and the burning practices of indigenous people.

“The computer simulations of fire show that the atmosphere of the Southern Hemisphere could have been very smoky in the century before the Industrial Revolution. Soot concentrations in the atmosphere were up to four times greater than previous studies suggested. Most of this was caused by widespread and regular burning practiced by indigenous peoples in the pre-colonial period,” said Jed Kaplan, Associate Professor at the University of Hong Kong and co-author of the study.

Drilling ice cores in East Antarctica as part of the Norwegian-U.S. International IPY Scientific Traverse of East Antarctica.

Drilling ice cores in East Antarctica as part of the Norwegian-U.S. International IPY Scientific Traverse of East Antarctica.

Credit: Mary Albert.

This result agrees with the ice core records that also show that soot was abundant before the start of the industrial era and has remained relatively constant through the 20th century. The modeling suggests that as land-use changes decreased fire activity, emissions from industry increased.

What does this finding mean for future surface temperatures?

By underestimating the cooling effect of smoke particles in the pre-industrial world, climate models might have overestimated the warming effect of carbon dioxide and other greenhouse gasses in order to account for the observed increases in surface temperatures.

“Climate scientists have known that the most recent generation of climate models have been over-estimating surface temperature sensitivity to greenhouse gasses, but we haven’t known why or by how much,” said Liu. “This research offers a possible explanation.”

“Clearly the world is warming but the key question is how fast will it warm as greenhouse gas emissions continue to rise. This research allows us to refine our predictions moving forward,” said Mickley.

The research was co-authored by Yang Li, Monica Arienzo, John Kodros, Jeffrey Pierce, Michael Sigl, Johannes Freitag, Robert Mulvaney, and Mark Curran.

It was funded by the National Science Foundation’s Geosciences Directorate under grants AGS-1702814 and 1702830, with additional support from 0538416, 0538427, and 0839093.

 

Additional Information:

The full text of the paper, Improved estimates of preindustrial biomass burning reduce the magnitude of aerosol climate forcing in the Southern Hemisphere, is available from Science Advances: https://advances.sciencemag.org/content/7/22/eabc1379.abstract

The news release above was reposted with permission from Harvard University: https://www.seas.harvard.edu/news/2021/05/fiery-past-sheds-new-light-future-global-climate-change. 

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About the Desert Research Institute
The Desert Research Institute (DRI) is a recognized world leader in basic and applied environmental research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policymakers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu

New DRI projects for 2021 include microplastics, microfossils, snowmelt risk, and solute transport

New DRI projects for 2021 include microplastics, microfossils, snowmelt risk, and solute transport

New DRI projects for 2021 include microplastics, microfossils, snowmelt risk, and solute transport

FEB 26, 2021
RENO & LAS VEGAS, NEV.

Introducing the winners of DRI’s 2021 Institute Project Assignment (IPA) competition.

Each year, the Desert Research Institute awards funding to several new faculty and staff projects each year through its Institute Project Assignment (IPA) competition. Winners of the IPA competition receive a research grant from DRI to pursue a topic that interests them and develop ideas that can ultimately be turned into externally funded research projects. This year, winners of the IPA competition are DRI scientists Erick Bandala, Monica Arienzo, Sandra Bruegger, Benjamin Hatchett, and Lazaro Perez. Details about each project are below.

Erick Bandala and Monica Arienzo: Assessing environmental aging of microplastics

Microplastics, defined as plastic fragments smaller than 5mm, were first discovered in the natural environment in the early 2000s. Two decades later, much is still unknown about these pollutants – including how microplastic particles degrade or break down as they age. A new project led by Erick Bandala, Ph.D., and Monica Arienzo, Ph.D., will assess the environmental aging of microplastic particles through accelerated aging tests, using UV-A radiation to imitate the effects of unfiltered sunlight over different time spans on microplastics of different types, shapes, and sizes. Their results will provide new insight into the fate of microplastics after their release into the environment.

Closeup of microplastic fibers

A close-up image of microplastic fibers. Credit: DRI.

Benjamin Hatchett and Anne Heggli: Towards improved decision support for snow-covered watersheds: A snowmelt risk advisory

Rain-on-snow events (in which a warm winter storm rains onto existing snowpack under windy and humid conditions) are linked to many of the largest floods in Nevada and other parts of the United States. These types of events are projected to increase in frequency and magnitude as the climate warms. This change creates new challenges for water managers, who are tasked with deciding when water should be stored in reservoirs for economic and ecological benefits, and when water should be released downstream for flood control and public safety. To help water managers make decisions using the best available data, Division of Atmospheric Sciences graduate student Anne Heggli, advised by Benjamin Hatchett, Ph.D., will design and develop a tool called a Snowmelt Risk Advisory (SRA). This framework will combine risk matrices with weather datasets to create a tool that will help inform reservoir operations in snow-dominated watersheds.

A ski lift at Kirkwood ski resort during a warm storm

A rain-on-snow event at Kirkwood Ski Area. Credit: Ben Hatchett/DRI.

Sandra Brugger: Microfossils in Greenland Ice – Establishing a new method at DRI

Greenland’s ice sheets hold important records of pollen grains and other microfossils that can provide researchers with insight into long-term environmental change in the Arctic, however, these resources have not yet been studied extensively. Recently, Sandra Brugger, Ph.D., developed a new method for extracting microfossils from Greenland ice cores and created the first reliable record of microfossils from well-dated Greenland ice, with a second record currently under development. With IPA funding, Bruegger will hold a workshop to train additional scientists in her methodology, and develop a microfossil record from east-central Greenland ice spanning the past 8000 years. She will also give a talk to the local community at the Alta Skilled Nursing and Rehabilitation Center in Reno, sharing her research with an audience that has been isolated for months during the pandemic.

DRI scientist Sandra Brugger inspects samples under a microscope. Credit: Manu Friederich

DRI scientist Sandra Brugger inspects samples under a microscope. Credit: Manu Friederich.

Lazaro Perez: Tortuosity Characterization via Machine Learning to Quantify Solute Transport in Berea Sandstone

Understanding and predicting the fate of solutes (dissolved substances) as they pass through various types of rocks and soils in a groundwater system is crucial for several environmental and industrial applications, but modeling this process is complex. Building on work completed as part of an IPA-funded project in 2020, Lazaro J. Perez, Ph.D., will use training data for the development of a machine-learning algorithm to predict solute transport through material containing pores of different sizes, such as sandstone. Dr. Perez’s work, focused on solute transport simulations on pore-scale images of two types of sandstones, will help scientists better understand processes as diverse as contaminant transport in groundwater flow and protein diffusion in living cells.

DRI scientist Lazaro Perez

DRI scientist Lazaro Perez.

Traditional hydrologic models may misidentify snow as rain, new citizen science data shows

Traditional hydrologic models may misidentify snow as rain, new citizen science data shows

Traditional hydrologic models may misidentify snow as rain, new citizen science data shows

FEB. 22, 2021
RENO, NEV.

Weather Forecasting
Climate
Citizen Science

Tahoe Rain or Snow weather spotters help reduce inaccuracies in estimating precipitation

Normally, we think of the freezing point of water as 32°F – but in the world of weather forecasting and hydrologic prediction, that isn’t always the case. In the Lake Tahoe region of the Sierra Nevada, the shift from snow to rain during winter storms may actually occur at temperatures closer to 39.5°F, according to new research from the Desert Research Institute (DRI), Lynker Technologies, and citizen scientists from the Tahoe Rain or Snow project.

The new paper, which published this month in Frontiers in Earth Science, used data collected by 200 volunteer weather spotters to identify the temperature cutoff between rain and snow in winter storms that occurred during the 2020 season. Their results have implications for the accuracy of water resources management, weather forecasting, and more.

“Scientists use a temperature threshold to determine where and when a storm will transition from rain to snow, but if that threshold is off, it can affect our predictions of flooding, snow accumulation, and even avalanche formation,” said Keith Jennings, Ph.D., Water Resources Scientist at Lynker Technologies and one of the lead authors on the study.

DRI scientist Monica Arienzo collects data for the Tahoe Rain or Snow project with Lake Tahoe in the distance.
From a backcountry area near Lake Tahoe, Desert Research Institute scientist Monica Arienzo collects field data from her smartphone for the Tahoe Rain or Snow project. January 2021.
Credit: DRI.
Thumbnail image of Tahoe Rain or Snow paper

The full text of the study “Enhancing Engagement of Citizen Scientists to Monitor Precipitation Phase” is available from Frontiers in Environmental Science: https://www.frontiersin.org/articles/10.3389/feart.2021.617594/full

Previous studies have found that thresholds used are particularly problematic in the Sierra Nevada, where a significant proportion of winter precipitation falls near 32°F. When the temperature is near freezing, weather forecasts and hydrologic models have difficulty correctly predicting whether it will be raining or snowing.

Tahoe Rain or Snow was launched in 2019 to take on the challenge of enhancing the prediction of snow accumulation and rainfall that may lead to flooding by making real-time observations of winter weather. The team is comprised of two scientists, one education specialist, and about 200 volunteer weather spotters from the Lake Tahoe and western slope regions of the Sierra Nevada and Truckee Meadows.

Tahoe Rain or Snow harnesses the power of hundreds of local volunteers. The real-time observations that they share with scientists add an incredible amount of value to the study of hydrology and clarify crucial gaps left by weather models,” said Meghan Collins, M.S., Education Program Manager for DRI and another lead author on the paper.

DRI scientist Meghan Collins collects data from her smartphone for the Tahoe Rain or Snow project
Closeup of smartphone displaying the Citizen Science Tahoe app
Above: Desert Research Institute scientist Meghan Collins collects data from her smartphone for the Tahoe Rain or Snow project using the Citizen Science Tahoe app during January 2021.

Credit: DRI (left) and Keith Jennings/Lynker Techologies (right)

In 2020, these citizen scientists submitted over 1,000 timestamped, geotagged observations of precipitation phases through the Citizen Science Tahoe mobile phone app.

Ground-based observations submitted by the Tahoe Rain or Snow team in 2020 showed that a much warmer temperature threshold of 39.5°F for splitting precipitation into rain and snow may be more accurate for our mountain region. In contrast, a 32°F rain-snow temperature threshold would have vastly overpredicted rainfall, leading to pronounced underestimates of snow accumulation. Such model errors can lead to issues in water resources management, travel planning, and avalanche risk prediction.

Tahoe Rain or Snow citizen scientists across our region open a door to improve our understanding of winter storms”, said Monica Arienzo, Ph.D., Assistant Research Professor of Hydrology at DRI and another lead author on the paper. “Growing our team of volunteer scientists is important given that climate change is causing the proportion of precipitation falling as snow to decrease, and they help enhance the predictions of precipitation that we rely on in the Sierra Nevada and Truckee Meadows.”

Tahoe Rain or Snow is continuing in 2021. To join, text WINTER to 877-909-0798. You will find out how to download the Citizen Science Tahoe app and receive alerts as to good times to send weather observations. Tahoe Rain or Snow particularly needs observations from sparsely populated, remote, or backcountry areas of the Sierra Nevada.

DRI scientist Monica Arienzo collects data for the Tahoe Rain or Snow project with a rainbow-colored umbrella
Desert Research Institute scientist Monica Arienzo collects field data from her smartphone for the Tahoe Rain or Snow project. January 2021.
Credit: DRI.

Additional Information:

This study was funded by Nevada NASA EPSCoR Grant 20-23, 19-40.

The full text of the study “Enhancing Engagement of Citizen Scientists to Monitor Precipitation Phase” is available from Frontiers in Environmental Science: https://www.frontiersin.org/articles/10.3389/feart.2021.617594/full

To learn more about the Tahoe Rain or Snow project, please visit: https://www.dri.edu/project/tahoe-rain-or-snow/

 

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The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policymakers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, please visit  www.dri.edu.

Lynker Technologies delivers innovative solutions to support global environmental sustainability and economic prosperity as a trusted partner to governments, communities, research institutions, and industry. We are passionate about what we do and the high value we provide to water resources management, hydrologic science, and conservation across the US and beyond. For more information, please visit https://www.lynker.com/.

People-powered research: Citizen science makes microplastics discovery at Lake Tahoe possible

People-powered research: Citizen science makes microplastics discovery at Lake Tahoe possible

Take a moment to picture a scientist who has made a groundbreaking discovery. What does that person look like?

Perhaps it’s a person in a white coat standing in a lab with microscopes and test tubes, or a distinguished professor accepting an award on stage.

What if we told you that you could have pictured yourself?

In citizen science projects, community members like you utilize their curiosity, enthusiasm, and talents alongside professional scientists in real-world research projects. They act as the eyes, ears, or an extra set of hands for scientists, helping to extend the spatial reach of a study or adding important perspectives that scientists cannot provide themselves.

That’s precisely what Lake Tahoe locals did this summer to help DRI scientists identify microplastic pollution in the Lake for the first time ever.

DRI microplastics researchers sample water from the shore of Lake Tahoe in spring 2019.

DRI microplastics researchers sample water from the shore of Lake Tahoe in spring 2019.

 

Why citizen science?
In fall of 2018, Desert Research Institute scientists Monica Arienzo, Zoe Harrold, and Meghan Collins were formulating a project to search for microplastic pollution in the surface waters of Lake Tahoe and in stormwater runoff into the lake. But the team was not satisfied in seeking to identify the presence of microplastic alone—they also wanted to make connections with community members in Tahoe.

“By involving citizen scientists in understanding the problem of microplastics,” explained Arienzo, “we can naturally connect the community to evidence-based solutions to reduce the microplastic problem.”

To recruit citizen scientists, DRI partnered with the League to Save Lake Tahoe, which runs the Pipe Keepers program. Pipe Keepers volunteers throughout the Tahoe Basin collect water samples from stormwater outfalls into Lake Tahoe and monitor for stormwater pollution.

These outfalls, which drain water from roadways, parking lots and neighborhoods into the lake, are a significant source of fine sediment pollution in Lake Tahoe, which threatens the clarity of Tahoe’s famous blue waters. They’re also a potential culprit of microplastic pollution since plastic litter, tires, and other sources can break down into smaller pieces and be swept away with the stormwater.

“Our citizen science programs are a great way to get locals and visitors directly engaged in protecting the Lake,” said Emily Frey, the League’s Citizen Science Program Coordinator. “We’re really excited to contribute to this groundbreaking research.”

Over the course of the 2019 field season, volunteer Pipe Keepers collected 24 liters of water from six sampling sites. Arienzo, Harrold, and Collins also pumped water samples from several places along the Lake’s shoreline surface waters for the study.

In both the stormwater samples and the surface water samples, a large portion of the microplastics found were small fibers, which can come from the breakdown of synthetic clothing. The stormwater represents a point-source of this microplastic pollution, which, in theory, could be mitigated in the future.

Meghan Collins in the Microplastics Lab at DRI's Reno campus, holding a sample collected by a Pipe Keeper. Credit: Cat Allison/Nevada Momentum.

Meghan Collins in the Microplastics Lab at DRI’s Reno campus, holding a sample collected by a Pipe Keeper. Credit: Cat Allison/Nevada Momentum.

Broad benefits
Beyond providing important data for research projects, citizen science also has the power to engage communities in scientific inquiry and inspire care for the places where we live and play.

Laura Schlim has been a volunteer with the Pipe Keepers program for three years, and she worked with the DRI team to collect samples for the microplastics project. The best thing about citizen science for her? It’s fun!

“I’m naturally interested in why things work a certain way,” explained Schlim, a certified California naturalist. “It’s fun to be part of something where I can contribute to the greater body of knowledge while also enjoying the natural world.”

Vesper Rodriguez, a Pipe Keeper since 2018, echoed this sentiment.

“I volunteer because I like to be outside and I have a lot of fun with the projects. Volunteering for the League’s Stewardship Days and their Pipe Keepers program in particular, which allows volunteers to monitor stormwater infrastructure, is really fulfilling,” Rodriguez said. “It’s a rewarding feeling to contribute to the community and the land that I live on.”

Since community members have been vested in the research from the start, the DRI team is optimistic that the findings of their work will be able to go far beyond the lab and begin to solve the microplastic pollution problem in Lake Tahoe.

“A core mission of the DRI team is to generate evidence-based solutions to microplastics in our water, by identifying sources that could be mitigated or finding techniques to better prevent microplastic generation in the first place,” said Collins. “Building a community of citizen scientists creates a strong network of engaged individuals who care and can implement these solutions as they are developed.”

DRI microplastics researchers (beginning top row, from center) Zoe Harrold, Meghan Collins, and Monica Arienzo pose with the Pipe Keeper volunteers on the project. Credit: League to Save Lake Tahoe.

DRI microplastics researchers (beginning top row, from center) Zoe Harrold, Meghan Collins, and Monica Arienzo pose with the Pipe Keeper volunteers on the project. Credit: League to Save Lake Tahoe.

The study on microplastics is one of many active citizen science projects led by DRI and the League to Save Lake Tahoe. DRI also leads Stories in the Snow and Tahoe: Rain or Snow?, projects related to weather and climate in the Sierra Nevada. In addition to the Pipe Keepers program, the League also runs Eyes on the Lake, which helps monitor and prevent the spread of aquatic invasive plants.

Interested in joining the team of citizen scientists in the Sierra Nevada and around Lake Tahoe? Download the Citizen Science Tahoe app to get started.

In addition to volunteering your time to this project, you can also financially support this research effort at the team’s crowdfunding page.

Lead pollution in Arctic ice shows economic impact of wars, plagues, famines from Middle Ages to present

Lead pollution in Arctic ice shows economic impact of wars, plagues, famines from Middle Ages to present

Photo: Dr. Joe McConnell and graduate student Nathan Chellman work in the ice lab at the Desert Research Institute, in Reno, Nev., on Wednesday, May 15, 2019. Photo by Cathleen Allison/Nevada Momentum.


 

RENO, Nev. (July 8, 2019) – How did events like the Black Death plague impact the economy of Medieval Europe? Particles of lead trapped deep in Arctic ice can tell us.

Commercial and industrial processes have emitted lead into the atmosphere for thousands of years, from the mining and smelting of silver ores to make currency for ancient Rome to the burning of fossil fuels today. This lead pollution travels on wind currents through the atmosphere, eventually settling on places like the ice sheet in Greenland and other parts of the Arctic.

Because of lead’s connection to precious metals like silver and the fact that natural lead levels in the environment are very low, scientists have found that lead deposits in layers of Arctic ice are a sensitive indicator of overall economic activity throughout history.

In a new study published in the Proceedings of the National Academy of Sciences, researchers from the Desert Research Institute (DRI), the University of Oxford, NILU – Norwegian Institute for Air Research, the University of Copenhagen, the University of Rochester, the Alfred Wegener Institute for Polar and Marine Research used thirteen Arctic ice cores from Greenland and the Russian Arctic to measure, date, and analyze lead emissions captured in the ice from 500 to 2010 CE, a period of time that extended from the Middle Ages through the Modern Period to the present.

This work builds on a study published by some of the same researchers in 2018, which showed how lead pollution in a single ice core from Greenland tracked the ups and downs of the European economy between 1100 BCE and 800 CE, a period which included the Greek and Roman empires.

“We have extended our earlier record through the Middle Ages and Modern Period to the present,” explained Joe McConnell, Ph.D., lead author on the study and Director of DRI’s Ultra-Trace Ice Core Chemistry Laboratory in Reno, Nevada. “Using an array of thirteen ice cores instead of just one, this new study shows that prior to the Industrial Revolution, lead pollution was pervasive and surprisingly similar across a large swath of the Arctic and undoubtedly the result of European emissions. The ice-core array provides with amazing detail a continuous record of European – and later North American – industrial emissions during the past 1500 years.”

“Developing and interpreting such an extensive array of Arctic ice-core records would have been impossible without international collaboration,” McConnell added.

The research team found that increases in lead concentration in the ice cores track closely with periods of expansion in Europe, the advent of new technologies, and economic prosperity. Decreases in lead, on the other hand, paralleled climate disruptions, wars, plagues, and famines.

“Sustained increases in lead pollution during the Early and High Middle Ages (about 800 to 1300 CE), for example, indicate widespread economic growth, particularly in central Europe as new mining areas were discovered in places like the German Harz and Erzgebirge Mountains, “McConnell noted. “Lead pollution in the ice core records declined during the Late Middle Ages and Early Modern Period (about 1300 to 1680 Ce) when plague devastated those regions, however, indicating that economic activity stalled.”

Even with ups and downs over time due to events such as plagues, the study shows that increases in lead pollution in the Arctic during the past 1500 years have been exponential.

“We found an overall 250 to 300-fold increase in Arctic lead pollution from the start of the Middle Ages in 500 CE to 1970s,” explained Nathan Chellman, a doctoral student at DRI and coauthor on the study. “Since the passage of pollution abatement policies, including the 1970 Clean Air Act in the United States, lead pollution in Arctic ice has declined more than 80 percent.”

“Still, lead levels are about 60 times higher today than they were at the beginning of the Middle Ages,” Chellman added.

This study included an array of ice cores and the research team used state-of-the-art atmospheric modeling to determine the relative sensitivity of different ice-core sites in the Arctic to lead emissions.

“Modeling shows that the core from the Russian Arctic is more sensitive to European emissions, particularly from eastern parts of Europe, than cores from Greenland,” explained Andreas Stohl, Ph.D., an atmospheric scientist at NILU and coauthor on the study. “This is why we found consistently higher levels of lead pollution in the Russian Arctic core and more rapid increases during the Early and High Middle Ages as mining operations shifted north and east from the Iberian Peninsula to Great Britain and Germany.”

Lead pollution found in 13 ice cores from three different regions of the Arctic (North Greenland, South Greenland, and the Russian Arctic) from 200 BCE to 2010 CE. Increases in lead deposition coincided with times of economic prosperity, such as the Industrial Revolution in the mid-19th century. Dramatic declines in lead pollution followed crises such as the Black Death Plague Pandemic starting about 1347 CE, as well as pollution abatement policies such as the 1970 U.S. Clean Air Act.

 

The combination of expertise on this study is unique, continuing collaboration between researchers in fields as different as ice-core chemistry and economic history. These results, the team argues, are a testament to the benefits of interdisciplinary collaboration.

“What we’re finding is interesting not just to environmental scientists who want to understand how human activity has altered the environment,” said Andrew Wilson, Ph.D., Professor of the Archaeology of the Roman Empire at Oxford and co-author on the study. “These ice-core records also are helping historians to understand and quantify the ways that societies and their economies have responded to external forces such as climate disruptions, plagues, or political unrest.”

Collection, analysis, and interpretation of the ice cores used in this study were supported by the U.S. National Science Foundation, NASA, the John Fell Oxford University Press Research Fund and All Souls College, Oxford, the German Ministry of Education and Research, the German Research Foundation, and the Desert Research Institute.

Locations of the 13 Arctic ice-core drilling sites, as well as ancient and medieval lead/silver mines throughout Europe. Atmospheric modeling shows the impact of emissions from different regions on pollution recorded in the Arctic ice cores. The Russian Arctic, for example, is relatively more sensitive to emissions from mines in eastern Europe, while North Greenland is relatively more sensitive to emissions from western Europe.

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The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policymakers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI is one of eight institutions in the Nevada System of Higher Education. Learn more at www.dri.edu, and connect with us on social media on Facebook, Instagram, and Twitter.

Media Contact:
Justin Broglio
Communications Manager, Desert Research Institute
This email address is being protected from spambots. You need JavaScript enabled to view it.”>Justin.Broglio@dri.edu
775-673-7610
@DRIscience 

Problem Plastic: Investigating Microplastic Pollution in Nevada’s Waterways

Problem Plastic: Investigating Microplastic Pollution in Nevada’s Waterways

Photo: A collection of marine debris including microplastics. Credit: NOAA Marine Debris Program/Flickr.


 

Microplastics research at DRI

Even the tiniest pieces of plastic are a big pollution problem.

Microplastics are plastic pieces ranging in size from 5mm to microscopic particles, in other words, the size of a pencil’s eraser or smaller. They come from a variety of sources, including the breakdown of larger products like single-use plastic bottles and from the microbeads in products like facewash and toothpaste.

The extent of microplastic pollution is only just beginning to be understood, with researchers discovering the tiny plastic pieces everywhere from the air we breathe to the deep ocean. Because microplastics are durable, insoluble, and potentially toxic, they could pose threat to natural ecosystems and human health. But to determine the impact of microplastic pollution, researchers must first understand just how much tiny plastic is out there and where it’s coming from.

 

 

DRI’s Monica Arienzo, Zoe Harrold, Meghan Collins, Xuelian Bai, and University of Nevada, Reno undergraduate Julia Davidson are exploring these questions in two bodies of freshwater in Nevada: Lake Tahoe and the Las Vegas Wash.

“There has been a lot of work done to understand how much microplastic is in marine environments, but there have been far fewer studies in freshwater, and far fewer even in alpine lakes,” explained Collins, Education Program Manager at DRI. “This study is really well placed to identify what microplastics may be in the water, their sources, and their characteristics.”

The research team is collecting samples from four different sites in Las Vegas—one in Lake Mead and three in the Las Vegas Wash—and six sites in Lake Tahoe. Sites were selected to include areas both high and low human activity, like the Tahoe Keys with significant boat traffic and Emerald Bay State Park where human impact is low. Additional sampling was also conducted at three stormwater outfalls into Lake Tahoe in collaboration with the League to Save Lake Tahoe’s Pipe Keepers citizen science program.

Research team sets up equipment at Lake Tahoe.

The research team sets up the pump and filter system at Lake Tahoe’s Emerald Bay State Park in May 2019.

 

“The sampling methods we’re using are unique,” said Arienzo, assistant research professor and project lead. “Past studies collected samples by trailing a large net from a boat or standing with it in a moving stream. Our approach is to sample and filter water in the field for microplastics using a pump, which allows us to filter upwards of 15 gallons of water in locations with still water and in places where boat access is limited.”

“Plus, we don’t have to haul netting around or carry the samples back to the lab—everything we need fits into a backpack, which makes sampling in remote and hard to access locations more feasible,” Arienzo added.

To make this novel method work, researchers place a stake with a funnel clipped to it about 20 feet from the water’s edge. The funnel, positioned on the surface of the water, is connected to tubing that runs back to the pump on shore, which draws water through the tubing and over a series of filters which can capture particles of different sizes.

Filter used to capture microplastic particles.

Tubing runs into the column of filters, which capture particles at three different sizes as water flows through.

 

Tubing runs into the column of filters, which capture particles at three different sizes as water flows through.

Sampling in all locations took place throughout the spring, and now the team is set to process and analyze the samples over the summer.

“To isolate the plastic pieces, we first have to get rid of all the organics, and we’re going to do that by oxidizing them,” explained Harrold, assistant research scientist in DRI’s Division of Earth and Ecosystem Sciences. “It’s a delicate balance between getting rid of the bugs and twigs and whatever else has ended up in there and not dissolving your plastics.”

Once the team oxidizes the organic particles left behind on the filters, they’ll separate the plastics from any remaining sediment using a high-density liquid separation method which will cause the sediments will settle to the bottom while plastics will float to the top.

From there, the team will begin identifying the different kinds of plastic pieces they find. The type of plastic, its size and shape, and the location where it was collected all provide clues about where it may have come from—for example, a nylon fiber may have come from the breakdown of synthetic clothing, and a piece of Styrofoam could have come from a single-use cup.

filter used to sample microplastics

Harrold removes a filter from the sampling instrument to bring it back to the lab for analysis.

 

However, making determinations about where individual pieces of microplastic originate is far from straightforward.

“We’re only discovering more sources of microplastics,” explained Harrold. “Recent studies have shown that microplastics can be transported through the atmosphere, so though some of what we find might be coming from local sources, the pollution could also be coming from a factory manufacturing plastic on the other side of the world. We just don’t know.”

While it’s daunting that there’s so much still unknown about this increasingly problematic pollutant, the research team also finds it exciting.

“This is the second study ever to be done on microplastics in Lake Tahoe,” said Arienzo. “It’s amazing to be a part of advancing the science in this new area of study.”

The team hopes that this work will contribute to a foundation of scientific information about the extent of microplastics pollution in Nevada freshwater so that scientists will be able to better identify the sources of microplastic, potential harmful effects to plant and animal life, and ways to remove it from the environment.

DRI's microplastics research team at Lake Tahoe

From left: Harrold, Arienzo, Collins, Davidson, and Bai after sampling at Emerald Bay in May 2019.

 

Funding for this project came from the DRI Foundation’s Innovation Research Program (IRP), which is designed to support DRI faculty and staff as they pursue their very best ideas. The IRP is funded by individual contributions from science enthusiasts like you—if you’d like to donate to the IRP and help make projects like this one possible, please visit: https://www.dri.edu/foundation/innovation-research-program.

Traces of Roman-era pollution stored in the ice of Mont Blanc

Traces of Roman-era pollution stored in the ice of Mont Blanc

Researchers drill ice cores from a field camp on Mont Blanc in the French Alps. Credit: B. Jourdain, L’Institut des Géosciences de l’Environnement.


 

RENO, Nev. (May 8, 2019) – Last spring, an international team of researchers led by Joe McConnell, PhD, Director of the Ultra Trace Ice Core Chemistry Laboratory at DRI’s campus in Reno, Nevada, traced significant atmospheric lead pollution from Roman-era mining and smelting of lead-silver ores in an ice core record from Greenland, providing new insights about the Roman economy.

Now working with colleagues at the Institute of Geosciences and the Environment in Grenoble, France, some members of the same research team have published findings that show a related record of pollution in an ice core from the Col du Dôme area of Mont Blanc in the French Alps.

Published in Geophysical Research Letters, the new study reveals significant atmospheric pollution from lead and antimony, another toxic heavy metal. This study is the first to document an ice core record of antimony, showing that Roman-era mining and smelting activities had implications beyond lead contamination.

 

Graph of study results.

Lead (black) and antimony (red) concentrations in ice from the Col du Dôme (CDD). On the bottom scale, age is indicated in years. Phases of increasing lead emissions were accompanied by a simultaneous rise in the presence of antimony – another toxic metal – in the alpine ice. The increases and decreases in heavy metal concentration in the ice correspond with boom times and crises in Roman-era economic history.

 

“This is the first study of antiquity-era pollution using Alpine ice,” explained lead author Susanne Preunkert, PhD, of the CNRS Institute of Geosciences and the Environment. “Our record from the Alps provides insight into the impact of ancient emissions on the present-day environment in Europe, as well as a comparison with more recent pollution linked to the use of leaded gasoline in the twentieth century.”

Compared to the lead pollution record obtained from a Greenland ice core in the previous study, which reflects heavy metal emissions from across Europe, the Mont Blanc ice core reflects influences from more local pollution sources.

“This study continues an international collaboration between ice core experts, historians, and atmospheric scientists,” said McConnell. “Cross-disciplinary research like this allows us to interpret the ice record in more detail, leading to a better understanding of the impacts of past human activities on the natural environment while also providing new, more quantitative information on those human activities.”

This research received support from the CNRS, ADEME, and the European Alpclim and Carbosol projects, as well as the Desert Research Institute.

The full study, titled “Lead and Antimony in Basal Ice From Col du Dome (French Alps) Dated With Radiocarbon: A Record of Pollution During Antiquity,” is available here.

François Maginiot of CNRS contributed to this release.

Forest fires accelerating snowmelt across western U.S., new study finds

Forest fires accelerating snowmelt across western U.S., new study finds

Kelly Gleason, assistant professor of environmental science and management at Portland State University, and crew head out in a recently burned forest to collect snow samples. Credit: Kelly Gleason/Portland State University


 

RENO, Nev. (May 2, 2019) – Forest fires are causing snow to melt earlier in the season, a trend occurring across the western U.S. that may affect water supplies and trigger even more fires, according to a new study by a team of researchers at Portland State University (PSU), the Desert Research Institute (DRI), and the University of Nevada, Reno.

It’s a cycle that will only be exacerbated as the frequency, duration, and severity of forest fires increase with a warmer and drier climate.

The study, published May 2 in the journal Nature Communications, provides new insight into the magnitude and persistence of forest fire disturbance on critical snow-water resources.

Researchers found that more than 11 percent of all forests in the West are currently experiencing earlier snowmelt and snow disappearance as a result of fires.

The team used state-of-the-art laboratory measurements of snow samples, taken in DRI’s Ultra-Trace Ice Core Analytical Laboratory in Reno, Nevada, as well as radiative transfer and geospatial modeling to evaluate the impacts of forest fires on snow for more than a decade following a fire. They found that not only did snow melt an average five days earlier after a fire than before all across the West, but the accelerated timing of the snowmelt continued for as many as 15 years.

“This fire effect on earlier snowmelt is widespread across the West and is persistent for at least a decade following fire,” said Kelly Gleason, the lead author and an assistant professor of environmental science and management in PSU’s College of Liberal Arts and Sciences.

Gleason, who conducted the research as a postdoctoral fellow at the Desert Research Institute, and her team cite two reasons for the earlier snowmelt.

First, the shade provided by the tree canopy gets removed by a fire, allowing more sunlight to hit the snow. Secondly and more importantly, the soot — also known as black carbon — and the charred wood, bark and debris left behind from a fire darkens the snow and lowers its reflectivity. The result is like the difference between wearing a black t-shirt on a sunny day instead of a white one.

In the last 20 years, there’s been a four-fold increase in the amount of energy absorbed by snowpack because of fires across the West.

Research team in snowy forest

Burned forests shed soot and burned debris that darken the snow surface and accelerate snowmelt for years following fire. Image Credit: Nathan Chellman/DRI.

“Snow is typically very reflective, which is why it appears white, but just a small change in the albedo or reflectivity of the snow surface can have a profound impact on the amount of solar energy absorbed by the snowpack,” said co-author Joe McConnell, a research professor of hydrology and head of the Ultra-Trace Ice Core Analytical Laboratory at DRI. “This solar energy is a key factor driving snowmelt.”

For Western states that rely on snowpack and its runoff into local streams and reservoirs for water, early snowmelt can be a major concern.

“The volume of snowpack and the timing of snowmelt are the dominant drivers of how much water there is and when that water is available downstream,” Gleason said. “The timing is important for forests, fish, and how we allocate reservoir operations; in the winter, we tend to control for flooding, whereas in the summer, we try and hold it back.”

Early snowmelt is also likely to fuel larger and more severe fires across the West, Gleason said.

“Snow is already melting earlier because of climate change,” she said. “When it melts earlier, it’s causing larger and longer-lasting fires on the landscape. Those fires then have a feedback into the snow itself, driving an even earlier snowmelt, which then causes more fires. It’s a vicious cycle.”

Gleason will continue to build on this research in her lab at PSU. She’s in the first year of a grant from NASA that’ll look at the forest fire effects on snow albedo, or how much sunlight energy its surface reflects back into the atmosphere.

Funding for the study was provided by the Sulo and Aileen Maki Endowment at the Desert Research Institute. Co-authors also included Monica Arienzo and Nathan Chellman from DRI and Wendy Calvin from the University of Nevada, Reno.

The full paper, “Four-fold increase in solar forcing on snow in western U.S. burned forests since 1999,” is available here.

Cristina Rojas of PSU’s College of Liberal Arts and Sciences contributed to this release.

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The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI is one of eight institutions in the Nevada System of Higher Education.

As Oregon’s only urban public research university, Portland State offers tremendous opportunity to 27,000 students from all backgrounds. Our mission to “Let Knowledge Serve the City” reflects our dedication to finding creative, sustainable solutions to local and global problems. Our location in the heart of Portland, one of America’s most dynamic cities, gives our students unmatched access to career connections and an internationally acclaimed culture scene. “U.S. News & World Report” ranks us among the nation’s most innovative universities.

Monica Arienzo receives Board of Regents 2019 Rising Researcher Award

Monica Arienzo receives Board of Regents 2019 Rising Researcher Award

Reno, Nev. (March 1, 2019): This week, the Nevada System of Higher Education (NSHE) Board of Regents awarded Monica Arienzo, Ph.D. of the Desert Research Institute (DRI) in Reno with its annual Rising Researcher Award. The honor is given annually to one NSHE faculty member from DRI, UNR, and UNLV.

Arienzo is an assistant research professor of hydrology with DRI’s Division of Hydrologic Sciences. She was recognized for her early-career accomplishments using geochemical tools to understand climatic changes of the past and human impacts to the environment, and for her commitment to sharing her research with the scientific community, the greater Nevada community, and with students.

As a member of DRI’s Ice Core Laboratory, Arienzo and her collaborators have published climate records extending 100,000 years into the past. Her work also has focused on emissions from anthropogenic processes since the industrial revolution. Using ice cores from Greenland, Antarctica, and the European Alps, this research demonstrated the geographic extent of anthropogenic emissions, variations in emissions through time, and sources of these emissions. Locally, her work includes a project partnering with a Nevada non-profit organization to assess the impact of pollutants to the Tahoe Basin snow and water resources.

“I am honored to receive this award,” Arienzo said. “I look forward to continuing this important work with our team at DRI to understand interactions between the environment, climate, and human activities.”

With her collaborators, Dr. Arienzo is at the forefront in development of new geochemical methods including extraction of small (<1µL) water samples from stalagmites, analysis of formation temperatures for carbonates, and novel dating techniques for ice cores. She is currently collaborating with researchers at eight different institutions in four countries on a variety of interdisciplinary research projects.

Since joining DRI, Dr. Arienzo has been the lead author on four and co-author on ten peer-reviewed manuscripts published in high-impact journals including Proceedings of the National Academy of Sciences, Environmental Science and Technology, and Earth and Planetary Science Letters.

Arienzo holds a B.A. in geology from Franklin and Marshall College and a Ph.D. in marine geology and geophysics from the University of Miami’s Rosenstiel School of Marine and Atmospheric Science. She joined DRI in 2014 as a Postdoctoral Fellow under the mentorship of Dr. Joe McConnell, and was promoted to Assistant Research Professor in 2016.

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The Desert Research Institute (DRI) is a recognized world leader in investigating the effects of natural and human-induced environmental change and advancing technologies aimed at assessing a changing planet. For more than 50 years DRI research faculty, students, and staff have applied scientific understanding to support the effective management of natural resources while meeting Nevada’s needs for economic diversification and science-based educational opportunities. With campuses in Reno and Las Vegas, DRI serves as the non-profit environmental research arm of the Nevada System of Higher Education.

DRI ice core research makes Discover magazine’s list of top breakthroughs in 2018

DRI ice core research makes Discover magazine’s list of top breakthroughs in 2018

Reno, Nev. (Thurs. January 17th) – For the second time, research out of the Ultra-trace Ice Core Chemistry Laboratory at the Desert Research Institute (DRI) in Reno, Nevada, has been named one of the year’s biggest scientific discoveries by Discover magazine.

The research, originally published in the Proceedings of the National Academies of Science last May, used ice samples from the North Greenland Ice Core Project (NGRIP) to measure, date, and analyze European lead emissions that were captured in Greenland ice between 1100 BC and AD 800. Their results provide new insights for historians about how European civilizations and their economies fared over time.

“Our record of sub-annually resolved, accurately dated measurements in the ice core starts in 1100 BC during the late Iron Age and extends through antiquity and late antiquity to the early Middle Ages in Europe, a period that included the rise and fall of the Greek and Roman civilizations,” said the study’s lead author Joe McConnell, Ph.D., Research Professor of Hydrology at DRI and Director of the Ice Core Lab. “We found that lead pollution in Greenland very closely tracked known plagues, wars, social unrest and imperial expansions during European antiquity.”

The research team on the project included scientists, archaeologists, and economists from the Desert Research Institute (DRI), the University of Oxford, NILU – Norwegian Institute for Air Research and the University of Copenhagen.

This is the second time research out of the DRI Ice Core Lab has been recognized in the Discover magazine round up of the year’s top science stories. In the January 2008 issue, findings on rising black carbon levels in Greenland ice cores during the industrial revolution made the magazine’s 2007 top 100 list.

“Selection of these findings as among the world’s top science stories of 2018 is very exciting for the members of our research group and our international collaborators. It is especially rewarding for me in that a largely ice core based study was selected as among the top stories in archaeology rather than in earth or environmental sciences. This all demonstrates the vast potential of highly interdisciplinary research teams working together.”

Other DRI researchers who worked on this study are Monica Arienzo, Ph.D., assistant research professor, and graduate student researcher Nathan Chellman.

First non-polar historical iodine record shows impact of fossil fuel emissions

First non-polar historical iodine record shows impact of fossil fuel emissions

Reno, Nev. (Nov. 13, 2018): A new ice core record from the French Alps shows impacts of fossil fuel emissions in the form of a steep increase in iodine levels during the second half of the 20th century, according to a study released this week by an international team of scientists from the Université Grenoble Alpes-CNRS of France, the Desert Research Institute (DRI) in Reno, Nev., and the University of York in England.

“Model and laboratory studies had suggested that atmospheric iodine should have increased during recent decades as a result of increasing fossil fuel emissions but few long-term records of iodine existed with which to test these model findings, and none in Western Europe where modeled iodine increases were especially pronounced,” said French researcher and lead author Michel Legrand, Ph.D.

Iodine is an important nutrient for human health, key in the formation of thyroid hormones. It is present in ocean waters, and is released into the atmosphere when Iodide (I-) reacts with ozone (03) at the water’s surface. From the atmosphere, iodine is deposited onto Earth’s land surfaces, and absorbed by humans in the foods that we eat.

The new study, published in the Proceedings of the National Academy of Sciences, was initiated after scientists observed a three-fold increase in iodine between 1950 and the 1990s measured in an ice core from the Col du Dome region of France. The core was collected by French scientists and analyzed in 2017 in DRI’s Ultra Trace Ice Core Analysis Laboratory.

 

Researchers examine an ice core sample drilled from Mont Blanc.

Researchers examine an ice core sample drilled from Mont Blanc. Credit: B. Jourdain, L’Institut des Géosciences de l’Environnement.

Although previous modeling simulations had indicated a similar increase in global iodine emissions during the 20th century, this new record provides the first ice core iodine record from outside of the polar regions.

“Iodine has been measured previously in polar ice cores but changes there largely can be attributed to variations in sea ice,” said Joe McConnell, Ph.D., research professor of hydrology and head of DRI’s ice core laboratory. “These variations mask the larger scale trends linked to fossil fuel emissions and changes in ozone chemistry. Our new iodine record extends from 1890 to 2000 and is from the French Alps, a part of the world where there are no sea ice influences.”

As part of this study, more than 120 meters (nearly 400 feet) of ice core from the French Alps was analyzed for iodine and a broad range of chemical species by a group of DRI researchers that included McConnell, Monica Arienzo, Ph.D., Nathan Chellman, and Kelly Gleason, Ph.D., using DRI’s unique continuous analytical system.

The study team then analyzed the ice core record alongside modeling simulations to investigate past atmospheric iodine concentrations and changes in iodine deposition across Europe. According to their results, the observed tripling of iodine levels in the ice during the 1950s to 1990s were caused by increased iodine emissions from the ocean.

An ice core sample is processed in DRI’s Ultra-Trace Ice Core Laboratory in Reno, Nev.

An ice core sample is processed in DRI’s Ultra-Trace Ice Core Laboratory in Reno, Nev. Credit: Joe McConnell/DRI.

Ozone in the lower atmosphere acts as an air pollutant and greenhouse gas. Because iodine emissions from the ocean occur when iodine in the water reacts with ozone in the lower atmosphere, the study results indicate that increased ozone levels are increasing the availability of iodine in the atmosphere – and also that iodine is helping to destroy this “bad” ozone.

“Iodine’s role in human health has been recognized for some time – it is an essential part of our diets,” said Lucy Carpenter, Ph.D., Professor with University of York’s Department of Chemistry. “Its role in climate change and air pollution, however, has only been recognized recently and the impact of iodine in the atmosphere is not currently a feature of the climate or air quality models that predict future global environmental changes.”

According to the World Health Organization, iodine deficiency remains a significant health problem in parts of Europe, including France, Italy and certain regions of Spain – regions that now appear to have received a boost in iodine levels in recent years.

“The silver lining in the findings of this study is that the increase in human-caused pollution during the latter half of the 20th century may be leading to an increase in the availability of iodine as an essential nutrient,” Legrand said.

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To view the study, titled Alpine ice evidence of a three-fold increase in atmospheric iodine deposition since 1950 in Europe due to increasing oceanic emissions, published in the journal Proceedings of the National Academy of Sciences on 12 November 2018, please visit:  http://www.pnas.org/content/early/2018/11/07/1809867115

Samantha Martin from the University of York contributed to this release.

The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. Learn more at dri.edu, and connect with us on social media on Facebook, Instagram and Twitter

Monica Arienzo receives Board of Regents 2019 Rising Researcher Award

Lead pollution in Greenland ice shows rise and fall of ancient European civilizations

Dr. Monica Arienzo inspects an ice core sample in the ice core lab at the Desert Research Institute in Reno, Nev. Photo credit: DRI.

Reno, NV (May 14, 2018): To learn about the rise and fall of ancient European civilizations, researchers sometimes find clues in unlikely places: deep inside of the Greenland ice sheet, for example.

Thousands of years ago, during the height of the ancient Greek and Roman empires, lead emissions from sources such as the mining and smelting of lead-silver ores in Europe drifted with the winds over the ocean to Greenland – a distance of more than 2800 miles (4600 km) – and settled onto the ice. Year after year, as fallen snow added layers to the ice sheet, lead emissions were captured along with dust and other airborne particles and became part of the ice-core record that scientists use today to learn about conditions of the past.

In a new study published in PNAS, a team of scientists, archaeologists and economists from the Desert Research Institute (DRI), the University of Oxford, NILU – Norwegian Institute for Air Research and the University of Copenhagen used ice samples from the North Greenland Ice Core Project (NGRIP) to measure, date and analyze European lead emissions that were captured in Greenland ice between 1100 BC and AD 800. Their results provide new insight for historians about how European civilizations and their economies fared over time.

“Our record of sub-annually resolved, accurately dated measurements in the ice core starts in 1100 BC during the late Iron Age and extends through antiquity and late antiquity to the early Middle Ages in Europe – a period that included the rise and fall of the Greek and Roman civilizations,” said the study’s lead author Joe McConnell, Ph.D., Research Professor of Hydrology at DRI. “We found that lead pollution in Greenland very closely tracked known plagues, wars, social unrest and imperial expansions during European antiquity.”

Map showing location of NGRIP ice core.

Map showing location of NGRIP ice core in relation to Roman lead/silver mines. Credit: DRI.

A previous study from the mid-1990s examined lead levels in Greenland ice using only 18 measurements between 1100 BC and AD 800; the new study provides a much more complete record that included more than 21,000 precise lead and other chemical measurements to develop an accurately dated, continuous record for the same 1900-year period.

To determine the magnitude of European emissions from the lead pollution levels measured in the Greenland ice, the team used state-of-the-art atmospheric transport model simulations.

“We believe this is the first time such detailed modeling has been used to interpret an ice-core record of human-made pollution and identify the most likely source region of the pollution,” said co-author Andreas Stohl, Ph.D., Senior Scientist at NILU.

Most of the lead emissions from this time period are believed to have been linked to the production of silver, which was a key component of currency.

“Because most of the emissions during these periods resulted from mining and smelting of lead-silver ores, lead emissions can be seen as a proxy or indicator of overall economic activity,” McConnell explained.

Using their detailed ice-core chronology, the research team looked for linkages between lead emissions and significant historical events. Their results show that lead pollution emissions began to rise as early as 900 BC, as Phoenicians expanded their trading routes into the western Mediterranean. Lead emissions accelerated during a period of increased mining activity by the Carthaginians and Romans primarily in the Iberian Peninsula and reached a maximum under the Roman Empire.

Graph of European lead emissions.

Chronology of European lead emissions that were captured in Greenland ice between 1100 BC and AD 800 in relation to major historic events. Credit: DRI.

The team’s extensive measurements provide a different picture of ancient economic activity than previous research had provided. Some historians, for example, had argued that the sparse Greenland lead record provided evidence of better economic performance during the Roman Republic than during the Roman Empire.

According to the findings of this study, the highest sustained levels of lead pollution emissions coincided with the height of the Roman Empire during the 1st and 2nd centuries AD, a period of economic prosperity known as the Pax Romana. The record also shows that lead emissions were very low during the last 80 years of the Roman Republic, a period known as the Crisis of the Roman Republic.

“The nearly four-fold higher lead emissions during the first two centuries of the Roman Empire compared to the last decades of the Roman Republic indicate substantial economic growth under Imperial rule,” said coauthor Andrew Wilson, Professor of the Archaeology of the Roman Empire at Oxford.

The team also found that lead emissions rose and fell along with wars and political instability, particularly during the Roman Republic, and took sharp dives when two major plagues struck the Roman Empire in the 2nd and 3rd centuries. The first, called the Antonine Plague, was probably smallpox. The second, called the Plague of Cyprian, struck during a period of political instability called the third-century crisis.

“The great Antonine Plague struck the Roman Empire in AD 165 and lasted at least 15 years. The high lead emissions of the Pax Romana ended exactly at that time and didn’t recover until the early Middle Ages more than 500 years later,” Wilson explained.

The research team for this study included ice-core specialists, atmospheric scientists, archaeologists, and economic historians – an unusual combination of expertise.

“Working with such a diverse team was a unique experience in my career as a scientist,” McConnell said. “I think that our results show that there can be great value in collaborating across disciplines.”

Analysis and interpretation of archived NGRIP2 ice-core samples were supported by the John Fell Oxford University Press Research Fund and All Souls College, Oxford, as well as the Desert Research Institute.

Photo of the project team.

The project team included an interdisciplinary team of researchers, including (left to right) Dr. Audrey Yau, ice core specialist and former DRI post-doc; Dr. Monica Arienzo, ice core specialist, DRI; Elisabeth Thompson, doctoral student, Oxford University; Professor Andrew Wilson, historian, Oxford University; and Professor Joe McConnell, ice core specialist, DRI.

 

Massive Antarctic Volcanic Eruptions Linked to Abrupt Southern Hemisphere Climate Changes Near the End of the Last Ice Age

Massive Antarctic Volcanic Eruptions Linked to Abrupt Southern Hemisphere Climate Changes Near the End of the Last Ice Age

Above: A 15-meter pan-sharpened Landsat 8 image of the Mount Takahe volcano rising more than 2,000 meters (1.2 miles) above the surrounding West Antarctic ice sheet in Marie Byrd Land, West Antarctica. Credit: Landsat Image Mosaic of Antarctica (LIMA). USGS and NASA, LIMA Viewer, https://lima.gsfc.nasa.gov/. Image Date: March 4, 2015


New findings explain synchronous deglaciation that occurred 17,700 Years Ago

Reno, NV (Sept. 5, 2017) – New findings published today in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) by Desert Research Institute (DRI) Professor Joseph R. McConnell, Ph.D., and colleagues document a 192-year series of volcanic eruptions in Antarctica that coincided with accelerated deglaciation about 17,700 years ago.

“Detailed chemical measurements in Antarctic ice cores show that massive, halogen-rich eruptions from the West Antarctic Mt. Takahe volcano coincided exactly with the onset of the most rapid, widespread climate change in the Southern Hemisphere during the end of the last ice age and the start of increasing global greenhouse gas concentrations,” according to McConnell, who leads DRI’s ultra-trace chemical ice core analytical laboratory.

Climate changes that began ~17,700 years ago included a sudden poleward shift in westerly winds encircling Antarctica with corresponding changes in sea ice extent, ocean circulation, and ventilation of the deep ocean. Evidence of these changes is found in many parts of the Southern Hemisphere and in different paleoclimate archives, but what prompted these changes has remained largely unexplained.

“We know that rapid climate change at this time was primed by changes in solar insolation and the Northern Hemisphere ice sheets,” explained McConnell. “Glacial and interglacial cycles are driven by the sun and Earth orbital parameters that impact solar insolation (intensity of the sun’s rays) as well as by changes in the continental ice sheets and greenhouse gas concentrations.”

“We postulate that these halogen-rich eruptions created a stratospheric ozone hole over Antarctica that, analogous to the modern ozone hole, led to large-scale changes in atmospheric circulation and hydroclimate throughout the Southern Hemisphere,” he added. “Although the climate system already was primed for the switch, we argue that these changes initiated the shift from a largely glacial to a largely interglacial climate state. The probability that this was just a coincidence is negligible.”

Furthermore, the fallout from these eruptions – containing elevated levels of hydrofluoric acid and toxic heavy metals – extended at least 2,800 kilometers from Mt. Takahe and likely reached southern South America.

Monica Arienzo works with an ice core sample at DRI.

Monica Arienzo, Ph.D., an assistant research professor of hydrology at DRI, loads an 18,000-year-old sample of the WAIS Divide ice core for continuous chemical analysis using DRI’s ultra-trace ice core analytical system in Reno, Nevada. Credit: DRI Professor Joseph R. McConnell, Ph.D.

How Were These Massive Antarctic Volcanic Eruptions Discovered and Verified?

McConnell’s ice core laboratory enables high-resolution measurements of ice cores extracted from remote regions of the Earth, such as Greenland and Antarctica. One such ice core, known as the West Antarctic Ice Sheet Divide (WAIS Divide) core was drilled to a depth of more than two miles (3,405 meters), and much of it was analyzed in the DRI Ultra-Trace Laboratory for more than 30 different elements and chemical species.

Additional analyses and modeling studies critical to support the authors’ findings were made by collaborating institutions around the U.S. and world.

“These precise, high-resolution records illustrate that the chemical anomaly observed in the WAIS Divide ice core was the result of a series of eruptions of Mt. Takahe located 350 kilometers to the north,” explained Monica Arienzo, Ph.D., an assistant research professor of hydrology at DRI who runs the mass spectrometers that enable measurement of these elements to as low as parts per quadrillion (the equivalent of 1 gram in 1,000,000,000,000,000 grams).

“No other such long-lasting record was found in the 68,000-year WAIS Divide record,” notes Michael Sigl, Ph.D., who first observed the anomaly during chemical analysis of the core. “Imagine the environmental, societal, and economic impacts if a series of modern explosive eruptions persisted for four or five generations in the lower latitudes or in the Northern Hemisphere where most of us live!”

Discovery of this unique event in the WAIS Divide record was not the first indication of a chemical anomaly occurring ~17,700 years ago.

“The anomaly was detected in much more limited measurements of the Byrd ice core in the 1990s,” notes McConnell, “but exactly what it was or what created it wasn’t clear. Most previous Antarctic ice core records have not included many of the elements and chemical species that we study, such as heavy metals and rare earth elements, that characterize the anomaly – so in many ways these other studies were blind to the Mt. Takahe event.”

DRI’s initial findings were confirmed by analysis of replicate samples from WAIS Divide, producing nearly identical results.

“We also found the chemical anomaly in ice from two other Antarctic ice cores including archived samples from the Byrd Core available from the University of Copenhagen and ice from Taylor Glacier in the Antarctic Dry Valleys,” said Nathan Chellman, a graduate student working in McConnell’s laboratory.

Extraction of the WAIS-Divide ice core and analysis in DRI’s laboratory were funded by the U.S. National Science Foundation (NSF).

“The WAIS Divide ice core allows us to identify each of the past 30,000 years of snowfall in individual layers of ice, thus enabling detailed examination of conditions during deglaciation,” said Paul Cutler, NSF Polar Programs’ glaciology program manager. “The value of the WAIS Divide core as a high-resolution climate record is clear in these latest results and is another reward for the eight-year effort to obtain it.”

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The Desert Research Institute (DRI) is a recognized world leader in investigating the effects of natural and human-induced environmental change and advancing technologies aimed at assessing a changing planet. For more than 50 years DRI research faculty, students, and staff have applied scientific understanding to support the effective management of natural resources while meeting Nevada’s needs for economic diversification and science-based educational opportunities. With campuses in Reno and Las Vegas, DRI serves as the non-profit environmental research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu.  

Black Carbon Emissions from Ancient Wildfires Linked to Historical Climate Conditions

Black Carbon Emissions from Ancient Wildfires Linked to Historical Climate Conditions

Monica Arienzo, PhD, assistant research professor of hydrology at DRI, demonstrates part of the black carbon analysis process in the clean room of DRI’s Ice Core Laboratory. Credit DRI.


DRI-led research team publishes longest ice core black carbon record to date

Reno, NV (Aug. 10, 2017): Smoky skies and burnt landscapes are the easily recognizable, local and immediate impacts of large wildfires. Long after these fires are gone, their emissions are cataloged and stored forever in ice covering the Earth’s polar regions.

New research, led by a team at the Desert Research Institute (DRI) in Reno, Nevada, has revealed that Earth’s ancient climate conditions affected large regional scale wildfires.

The new study identifies a link between the concentration of wildfire black carbon (BC) emissions —a type of biomass-burning aerosol particle commonly known as soot—found in Antarctic ice cores and climate conditions in the Southern Hemisphere during the mid-Holocene, about 6,000 years ago.

Led by Monica Arienzo, PhD, an assistant research professor of hydrology at DRI, a team of international researchers used DRI’s unique ultra-trace ice core analytical laboratory to measure BC concentrations in two Antarctic ice cores, ice that contains traces of compounds present in the atmosphere at the time the snow fell. This method allowed researchers to make comparisons to other records, such as lake and marine sediment cores, and develop a high-resolution record of biomass-burning emissions in the Southern Hemisphere from 14 to 2.5 thousand years before present day.

“This is the longest ice core black carbon record published to date,” Arienzo said, “and it tells us a fascinating story about wildfire.”

The new ice core record illustrates that, during the mid-Holocene, decreases in precipitation and soil moisture coupled with increases in temperature and fire season length in regions of South America were mirrored by increased concentrations of BC in Antarctic ice.

“Our analysis gives us a sense of what climate-fire relationships were like before significant human-caused changes to the climate,” explained Joe McConnell, PhD, a study co-author and research professor of hydrology at DRI. “Knowing what climate-fire relationships were like in the past will help scientists make more accurate climate models because they can account for BC contributions from wildfires in addition to those from human sources.”

BC acts as an agent of climate forcing, a process which occurs in the atmosphere when the amount of incoming energy is greater than the amount of outgoing energy, “forcing” the planet to adjust by releasing energy as heat and warming up. This is a natural process, catalyzed by events such as large volcanic eruptions and changes in the sun’s energy output; however, human-caused climate forcing in the form of BC emissions, has increased dramatically since the Industrial Revolution and now is a significant climate forcing agent, second only to carbon dioxide (CO2).

BC also impacts ice sheet albedo, the reflectivity of a surface. Ice and snow have a high albedo because they are very white and reflect much of the sun’s energy. This reflectivity keeps the snow and ice cold and delays melting. Conversely, snow and ice with BC deposits have a lower albedo, causing increased absorption of energy into the snow and ice and more rapid melting.

“Recent precipitation models indicate vast regional changes in rainfall in the Southern Hemisphere in the future,” Arienzo added. “Our findings indicate that such rainfall changes may be accompanied by changes in Southern Hemisphere wildfires. Given that BC emissions from human sources are predicted to increase, our findings are an important factor for climate predictions involving BC impacts.”

The full version of the study—“Holocene black carbon in Antarctica paralleled Southern Hemisphere climate”—is available online at – http://onlinelibrary.wiley.com/doi/10.1002/2017JD026599/full

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The Desert Research Institute (DRI) is a recognized world leader in investigating the effects of natural and human-induced environmental change and advancing technologies aimed at assessing a changing planet. For more than 50 years DRI research faculty, students, and staff have applied scientific understanding to support the effective management of natural resources while meeting Nevada’s needs for economic diversification and science-based educational opportunities. With campuses in Reno and Las Vegas, DRI serves as the non-profit environmental research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu.