The 2000 Aljoya Consensus Statement on Long-Range Transport in the North Pacific
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Long-range atmospheric transport of contaminants in the Pacific Ocean region north of the equator, as elsewhere in the world, increases the risk of adverse effects to wildlife, ecosystems, climate, and human health and livelihood. Current levels of contaminants transported to and deposited in the north Pacific region are of concern. Unless preventative measures are taken, levels will increase due to continued economic growth in the region and the rest of the world.
Long-range transport of contaminants in the north Pacific is one of many inter-continental and trans-oceanic pathways of concern within a larger context of global atmospheric exchange of contaminants in which all countries participate as both sources and receptors. Other pathways of concern include Saharan dust transport over the tropical Atlantic to the Americas, North American pollutant movement across the North Atlantic, European pollution carried to Asia, and the transport of northern Eurasian contaminants over the frozen Arctic Ocean.
There are numerous atmospheric routes by which contaminants can be carried to and across the Pacific Ocean basin. Research on these Pacific pathways and our understanding of attendant physical, chemical, and biological effects due to natural and anthropogenic emissions, transport, transformation, and deposition of contaminants in the region is still in the formative stages. Existing knowledge is scattered among a wide variety of disciplines, programs, and individual research projects. To date, no attempt has been made to synthesize, summarize, and evaluate the various strands of research.
For this reason, an international and multidisciplinary group of over 100 experts gathered at the Aljoya Conference Center in Seattle, Washington, USA, 27-29 July 2000 for the First International Conference on Trans-Pacific Transport of Atmospheric Contaminants. Participants included experts in the fields of energy and emissions, atmospheric sciences, marine sciences, biogeochemistry, forestry, biological sciences, and international environmental policy. The objectives of the conference were to:
- Discuss the state of science on long-range atmospheric transport of contaminants in the North Pacific region, including identifying initial conclusions to be drawn from existing data;
- Discuss scientific research needs required to clarify uncertainties and gaps in our knowledge;
- Promote a network of individuals and organizations in the Pacific and other regions interested in addressing the emission, transport, transformation, deposition, and effects of atmospheric contaminants transported in the Pacific region.
The conference Steering Committee (Appendix 1) finalized this consensus statement, which was developed with input from all conference participants (Appendix 2) acting in an individual and unofficial capacity. The three-day conference included presentations, small group discussions broken out by specialty, a plenary session of open discussion on a draft of the statement, and finalizing of the statement by the conference Steering Committee.
· A large number of contaminants released into the global atmosphere as a result of human activity and natural processes can affect the Pacific region. Contaminants include: gaseous species such as ozone; aerosols such as sulfates; persistent organic pollutants (POPs) such as DDT; heavy metals such as mercury; and radionuclides such as cesium-137.
· Lower atmospheric circulation patterns that carry contaminants in the Pacific region north of the equator include the equatorial northeasterly trade winds and the mid-latitude westerlies. In the middle to upper troposphere, west to east concentric atmospheric flows around the pole tend to prevail. Persistent climatological featuressuch as the Siberian High, the Aleutian Low, sub-tropical high pressure cells, and the inter-tropical convergence zone (ITCZ)and topographically affected winds, vertical mixing, and precipitation, result in highly variable contaminant pathways across the Pacific.
· Patterns of long-range transport and deposition of atmospheric contaminants in the Pacific region are modulated in large part by variations in emissions and meteorological conditions, and by global ocean circulation.
· On a seasonal basis, gaseous and aerosol contaminants introduced into the north Pacific airshed can be transported thousands of kilometers in less than a week. For example, during the winter-spring period at latitudes greater than 20° N, eastward transport of atmospheric contaminants occurs off the land masses in the western portion of the Pacific Rim, while during the summer months westward transport on the tradewinds occurs from North and Central America.
· Evidence shows that some of the contaminants transported in the north Pacific region originate outside the region.
· Rates of deposition of contaminants are influenced by meteorological and topographical conditions, and air-surface exchange processes.
· Visible contaminant layers have been detected over remote and pristine continental areas and tracked to long-range transport in the north Pacific region.
· Mineral dust aerosols originating primarily in the deserts and drylands of Asia are periodically transported long distances through the atmosphere into and across the Pacific Ocean basin. There is great seasonal (strongest in winter and spring) and inter-annual variation modulated by synoptic and mesoscale weather patterns. Atmospheric dust events in downwind areas are highly episodic.
· Long-range atmospheric transport of biomass burning contaminants emitted to the Pacific region from Southeast Asia, Siberia, and North and Central America represents a significant source of contaminants to the north Pacific. It varies significantly from year to year.
· The chemistry of the troposphere above the Pacific Ocean and of the ocean itself, and contaminant concentrations in terrestrial and aquatic systems, could be significantly impacted due to long-range atmospheric transport.
· Some airborne chemicals, especially organochlorines and mercury, have the potential to enter foodwebs and biomagnify thereby increasing the toxicological risk to top predators, including humans.
· Ocean productivity could be altered by airborne chemicals (for example, nutrients like nitrates and iron) carried from continents and deposited to the Pacific Ocean. Changes in air-surface exchange processes could follow.
· The radiative forcing of the atmosphere over the Pacific Ocean could be changed by airborne contaminants, with implications for global climate change. In turn, global climate change could shift and alter the sources and sinks of contaminants in the Pacific region.
· The suspension, transport, and deposition of dust-borne chemicals to the Pacific and surrounding regions may increase due to desertification exacerbated by human activities.
· Air quality in some areas of the Pacific region, including remote locations, may be negatively affected due to primary or incremental burdens of windblown dust and contaminants transported from distant sources.
· Seasonally and annually varying biomass burning events could contribute to long-term alteration of atmospheric, and possibly marine, chemistry in the Pacific region.
A. What are the contributions of anthropogenic emissions in Asia, Europe, and North America to atmospheric contaminant concentrations and deposition in the Pacific region and how will these change in the future?
To answer this question we need to:
- Develop improved contaminant emission inventories with particular emphasis on those substances for which no inventories now exist;
- Conduct integrated process studies to better understand transport, transformation, and air-surface exchange of contaminants;
- Broaden the geographical range and temporal coverage of systematic atmospheric measurements in the Pacific region to include as many contaminants as necessary, as well as vertical profiles, while standardizing and coordinating between programs and nations.
B. How do atmospheric concentrations and deposition of contaminants affect terrestrial and marine ecosystems and human health in the Pacific region?
To answer this question we need to:
- Study deposition processes of contaminants in the Pacific region and the associated feedback of deposition on atmospheric composition;
- Undertake whole system studies that follow contaminants from atmospheric deposition through terrestrial and aquatic pathways to biological exposure and toxicological effects;
- Determine geographic distributions and trends of contaminants in freshwater, marine, and terrestrial biota in the Pacific region, and the forces that cause the observed variability;
- Quantify the risks to humans and marine and terrestrial ecosystems in the Pacific region due to exposure to contaminants.
C. How do atmospheric contaminants in the Pacific region affect regional and global climate?
To answer this question we need to:
- Conduct process oriented closure experiments of the direct radiative forcing of contaminants and dust in the Pacific basin;
- Apply satellite and other observations to the analysis of radiative perturbations from anthropogenic aerosols and greenhouse gases over the Pacific;
- Investigate the impact of aerosols on cloud distributions, radiative properties, and precipitation in the Pacific region.
In conclusion, the widespread distribution of contaminants in the Pacific
region, coupled with the expected expansion of human activities, requires
that we develop a common scientific understanding of the complex dynamics
of long-range transport of atmospheric contaminants in the region. We
recommend a Pacific Environmental Research Strategy be developed
to promote cooperation and coordination between disciplines, programs,
countries, and international organizations.
APPENDIX 1: Steering Committee
Prof. AKIMOTO Hajime
Director, Atmospheric Composition Research Program
Institute for Global Change Research, Japan
Dr. Leonard A. BARRIE (Chair)
Chief Scientist, Atmospheric Chemistry
Atmospheric Sciences and Global Change Resources
Pacific Northwest National Laboratory
U.S. Department of Energy
Prof. Jules M. BLAIS
University of Ottawa
Prof. Thomas A. CAHILL
University of California-Davis
Prof. Greg CARMICHAEL
University of Iowa
Dr. Sergei CHICHERIN
Deputy Director, Main Geophysical Observatory, Russia
Mr. ENDO Hajime
Assistant Director, Air Pollution Control Division
Environment Agency of Japan
Mr. Bruce HICKS
Director, Air Resources Laboratory
National Atmospheric and Oceanic Administration
Prof. Barry HUEBERT
University of Hawaii
Prof. Rudolf HUSAR
Prof. Daniel JACOB
Prof. Daniel JAFFE
University of Washington-Bothell
Dr. Carey JANG
Environmental Scientist, Air Quality Modeling Group
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Prof. Shaw LIU
Georgia Power/GRA Eminent Scholar and Professor
School of Earth and Atmospheric Sciences
Georgia Institute of Technology
Dr. Robie W. MACDONALD
Institute of Ocean Sciences
Department of Fisheries and Oceans, Canada
Dr. Suzanne K. M. MARCY
Senior Scientist in Ecology
National Center for Environmental Assessment
U.S. Environmental Protection Agency
Dr. Don C. MCKAY
Director, Air Quality Research Branch
Meteorological Service of Canada
Dr. MURANO Kentaro
Senior Research Scientist
Global Environment Research Division
National Institute for Environmental Studies, Japan
Prof. PARK Soon-Ung
Seoul National University
Dr. Keith PUCKETT
Chief, Air Quality Processes Research Division
Air Quality Research Branch
Dr. Frank SCHIERMEIER
Director, Atmospheric Modeling Division
National Exposure Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Dr. David STONE
Director, Northern Science and Contaminants Research
Department of Indian Affairs and Northern Development, Canada
Dr. TANG Xu
General Director, Institute of Strategy Development & Overall Planning
China Meteorological Agency
Dr. Kathy TONNESSEN
Research Coordinator, Rocky Mountain Cooperative Ecosystem Study Unit
National Park Service
Mr. TU Ruihe
Deputy Director, Division of Bilateral Cooperation, Department of International Cooperation
State Environmental Protection Administration of China
Dr. WANG Mingxing
Director, Institute of Atmospheric Physics
Chinese Academy of Science
Ms. Marilyn ENGLE
Office of International Activities
U.S. Environmental Protection Agency
Dr. Kenneth E. WILKENING
APPENDIX 2: Participants List
Jules M. BLAIS University of Ottawa
Larry FUNNELL Environment Canada-British Columbia & Yukon Region
Patrick HIGGINS Canadian Consulate, Seattle
Nick HUMPHREYS Canadian Forest Service / Pacific Forestry Centre
Robie W. MACDONALD Department of Fisheries and Oceans / Institute of Ocean Sciences
John MCEWEN Department of Indian Affairs and Northern Development / Northern Contaminants Program
Don C. MCKAY Environment Canada / Meteorological Service of Canada
Ian G. MCKENDRY University of British Columbia
Don MUNTON University of Northern British Columbia
Keith PUCKETT Environment Canada / Meteorological Service of Canada
Peter S. ROSS Department of Fisheries and Oceans / Institute of Ocean Sciences
D. Patrick SHAW Environment Canada / Aquatic and Atmospheric Sciences Division
David STONE * Department of Indian Affairs and Northern Development / Northern Contaminants Program
Bruce THOMSON Environment Canada / Aquatic and Atmospheric Sciences Division
CHAI Fahe Chinese Research Academy of Environmental Sciences / Center
for Environmental Assessment
HU Min Peking University, Center for Environmental Sciences
TANG Dagang Chinese Research Academy of Environmental Sciences / Air Research Institute
TANG Xu China Meteorological Agency
TU Ruihe State Environmental Protection Administration of China
WANG Mingxing Institute of Atmospheric Physics
WANG Yanjia Energy and Environmental Technology Center, Tsinghua University
AKIMOTO Hajime * Institute for Global Change Research
ENDO Hajime Environment Agency of Japan
MUKAI Hitoshi National Institute for Environmental Studies
MURANO Kentaro National Institute for Environmental Studies, Global Environment Research Division
MURAYAMA Toshiyuki Tokyo University of Mercantile Marine
SHIBATA Yasuyuki National Institute for Environmental Studies, Environmental Chemistry Division
UNO Itsushi Kyushu University
Simon WILSON Arctic Monitoring and Assessment Program
Paul J. MILLER Commission for Environmental Cooperation
Sergei CHICHERIN Main Geophysical Observatory
Alexey GUSEV Meteorological Synthesizing Centre-East, European Monitoring and Evaluation Program
Vasili F. MISHUKOV Pacific Oceanological Institute
KIM Byung-Gon National Institute of Environmental Research
PARK Soon-Ung Seoul National University
Renata BAILEY Montclair State University
Leonard A. BARRIE Department of Energy / Pacific Northwest National Laboratory
Timothy S. BATES National Oceanic and Atmospheric Administration / Pacific Marine Environmental Laboratory
Andrea BLAKESLEY National Park Service / Denali National Park and Preserve
Carol BOHNENKAMP Environmental Protection Agency / Region 9 (Arizona, California, Hawaii, Nevada, & the Pacific Islands)
Michael R. BOYER Washington Department of Ecology / Air Quality Program
Cathy CAHILL University of Alaska-Fairbanks
Thomas A. CAHILL University of California-Davis
John CALDER National Atmospheric and Oceanic Administration / Office of Oceanic and Atmospheric Research
Greg CARMICHAEL University of Iowa
Mark COHEN National Atmospheric and Oceanic Administration / Air Resources Laboratory
Doug DASHER State of Alaska Department of Environmental Conservation
John DIAMANTE Environmental Protection Agency / Office of International Activities
Stan DURKEE Environmental Protection Agency / Office of Research and Development
Richard C. EASTER Department of Energy / Pacific Northwest National Laboratory
Sylvia A. EDGERTON Department of Energy / Pacific Northwest National Laboratory
Robert EDMONDS University of Washington
Marilyn ENGLE Environmental Protection Agency / Office of International Activities
Fred FEHSENFELD National Oceanic and Atmospheric Administration / Aeronomy Laboratory
Jeremy HALES North American Research Strategy for Tropospheric Ozone (NARSTO) Secretariat
Shelley HALL National Park Service / Olympic National Park
Edward HEITHMAR Environmental Protection Agency / Office of Research and Development
Bruce HICKS National Atmospheric and Oceanic Administration / Air Resources Laboratory
Shieh-Tsing HSIEH Tulane University
Barry HUEBERT University of Hawaii
Rudolf HUSAR * Washington University
Mahbubul ISLAM Environmental Protection Agency / Region 10 (Pacific Northwest & Alaska)
Daniel JACOB Harvard University
Daniel JAFFE University of Washington-Bothell
Carey JANG Environmental Protection Agency / Office of Air Quality Planning and Standards
Terry KEATING Environmental Protection Agency / Office of Air and Radiation
James D. KILGROE Environmental Protection Agency / Office of Research and Development
Robert KOTCHENRUTHER University of Washington
Dixon LANDERS Environmental Protection Agency / National Health and Environmental Effects Research Laboratory
Matt LANDIS Environmental Protection Agency / Office of Research and Development
Ann LESPERANCE Environmental Protection Agency / Region 10 (Pacific Northwest & Alaska)
Hiram LEVY National Atmospheric and Oceanic Administration / Geophysical Fluid Dynamics Lab
Shaw LIU Georgia Institute of Technology, School of Earth and Atmospheric Sciences
Jennifer LOGAN Harvard University
Winston LUKE National Atmospheric and Oceanic Administration / Air Resources Laboratory
Suzanne MARCY Environmental Protection Agency / National Center for Environmental Assessment
Denise MAUZERALL Princeton University
Don MCNERNY California Air Resources Board
Amanda MOSES University of Washington
Masami NAKATA Nautilus Institute
Peter NEITLICH National Park Service / Forest Health Monitoring Program
Lee OTIS Environmental Protection Agency / Region 10 (Pacific Northwest & Alaska)
William T. PENNELL Department of Energy, Pacific Northwest National Laboratory
Kevin PERRY San Jose State University
Mahesh J. PHADNIS Princeton University
Eric PRESTBO Frontier Geosciences
Heather PRICE University of Washington
William RICE National Park Service / Alaska Support Office
Judy ROCCHIO National Park Service / Pacific West Region
Regina M. ROCHEFORT National Park Service / North Cascades National Park
Barbara SAMORA National Park Service / Mount Rainier National Park
Frank SCHIERMEIER Environmental Protection Agency / Office of Research and Development
Russ SCHNELL National Oceanic & Atmospheric Administration / Climate Monitoring & Diagnostics Laboratory
Marianne G. SEE State of Alaska Department of Environmental Conservation
Dennis SMITH National Energy Technology Laboratory
Leigh SMITH National Park Service / North Cascades National Park
Qingyuan SONG Ford Research Laboratory
Doug STEELE Environmental Protection Agency / Office of Research and Development
Robert K. STEVENS Environmental Protection Agency / Office of Research and Development
Kathy TONNESSEN National Park Service / Rocky Mountain Cooperative Ecosystem Study Unit
Tony VAN CUREN California Air Resources Board
Bronwen WANG United States Geological Survey
Douglas L. WESTPHAL Naval Research Laboratory at Monterey
Pai-Yei WHUNG National Atmospheric and Oceanic Administration / Office of Oceanic and Atmospheric Research
Ken WILKENING Nautilus Institute
An asterisk designates a member of the Conference Steering Committee who was unable to attend the conference.