~ for immediate release

news release March 25, 2007

Contact: Heather Emmons, DRI PIO, heather.emmons@dri.edu, Reno (775) 673-7313 (w), (702) 743-3435 (c)
Dr. Joseph McConnell, Research Professor, joe.mcconnell@dri.edu, (775) 673-7348
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High resolution graphic of Joe McConnell located at: http://news.dri.edu/highresimg/joemc.jpg
High resolution graphic of drilling: http://news.dri.edu/highresimg/Drilling_icecores.jpg
High resolution graphic of analysis: http://news.dri.edu/highresimg/Analyzing_icecore.jpg
High resolution map: http://news.dri.edu/highresimg/MapRGBbigger.jpg

Dust in Antarctic ice reveals important climate clues, new published DRI study shows

Dr. Joseph McConnell	Drilling ice cores on the polar ice sheet
Analyzing James Ross Island ice core in DRI's one-of-a-kind Ultra-Trace Chemistry Lab	Map of James Ross Island

Reno, Nev.—Recent climate warming and land use changes may be altering atmospheric dustiness over the Antarctic Peninsula and the nearby oceans, according to a new study being released in the March 26-30 online Early Edition of the Proceedings of the National Academy of Sciences.

Atmospheric dust, climate, and landscape are connected in many ways. Atmospheric dust refers to very small particles of soil that are eroded from arid parts of continents and suspended in air. Warm or dry weather, combined with removal of plant cover through clearing of forests, grazing, and burning generally make soils more vulnerable to wind erosion, leading to increased atmospheric dust. While past studies of ice cores have linked high levels of atmospheric dust with large decreases in global air temperature at the end of the last ice age, there are few reliable records from recent decades and centuries when natural processes and human activities have altered climate and the landscape.

In a landmark study funded primarily by the Fulbright Program, the U.S. National Science Foundation and the Instituto Antárctico Argentino, DRI's Dr. Joseph McConnell and colleagues measured total aluminum—a metal found almost exclusively in dust from the Earth's crust—in a 120 meter long ice core obtained from James Ross Island at the northern tip of the Antarctic Peninsula. The highly detailed record of soil dust spans the period 1832 to 1991 and shows that dust deposited from the air onto James Ross Island more than doubled during the 20th century. This increase closely paralleled measured air temperature increases of approximately 1oC in the Southern Hemisphere and southern South America over the same period, with high dust levels in the Antarctic Peninsula corresponding to warm and dry conditions during spring and summer in Patagonia and southern South America.

“To our knowledge, this is the first record that shows a close correspondence between recent climate warming and increases in atmospheric dust,” said lead author McConnell.

“Atmospheric dust is important to climate change in a number of ways,” added co-author Dr. Ross Edwards, also of DRI. “For example, dust from arid continental regions is picked up by wind storms and transported all over the globe. When it falls on the ocean, the dust releases essential nutrients such as iron. Plankton living near the surface of the ocean use up these nutrients and, in the process, take up carbon dioxide from the atmosphere. As the plankton die and are consumed by other organisms, some of the carbon—which was originally in the form of carbon dioxide—falls to the bottom of the ocean removing it from the atmosphere. Thus, dust fertilization of the ocean may directly affect atmospheric concentrations of important greenhouse gases, such as carbon dioxide."

Widespread deforestation and overgrazing have also occurred in southern South America during the 20th century, leading to extensive desertification in the region.

“Although the record is not long enough for us to quantify how much of the recent increase in dust is the result of climate warming and how much is the result of such extensive land degradation, it seems likely that human activities have amplified the impact of climate warming on atmospheric dust,” McConnell said. “More than 600 miles of open ocean separate Antarctica from the tip of South America so we were quite surprised to see that for more than 80 years, climate warming and probably human-caused desertification in Patagonia have very noticeably altered dust levels in the atmosphere and precipitation over the northern Antarctic Peninsula and surrounding regions of the Southern Ocean.”

ABOUT PNAS: PNAS is one of the world's most-cited multidisciplinary scientific serials. Since its establishment in 1914, it continues to publish cutting-edge research reports, commentaries, reviews, perspectives, colloquium papers and actions of the Academy. Coverage in PNAS spans the biological, physical, and social sciences. PNAS is published weekly in print, and daily online in PNAS Early Edition.

ABOUT DRI: A nonprofit, statewide division of the Nevada System of Higher Education, or NSHE, DRI pursues a full-time program of basic and applied environmental research on a local, national, and international scale.  More than 500 full- and part-time scientists, technicians, and support staff conduct more than 300 research projects at DRI annually.  DRI generates $50 million in total revenue consisting predominately of competitively won research contracts and grants. The State of Nevada provides critical funding in support of DRI's administration, operations, and maintenance through the NSHE education budget.  While DRI’s portion of the NSHE budget is approximately one percent, the institute leverages these funds to enhance its competitiveness.