The Global Effort to
Understand Carbon Dioxide
James R. Mahoney, Ph.D.Assistant Secretary of Commerce for Oceans and Atmosphere
NOAA Deputy Administrator Director: US Climate Change Science Program
September 26, 2005
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Outline
Carbon Dioxide Variability
Role of Atmosphere in Carbon Cycle
Role of Oceans in Carbon Cycle
Role of Terrestrial Processes in Carbon Cycle
Future Directions in Assessing the Carbon Cycle
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Long Term Record of Atmospheric CO2
Increase in CO2 in the past 100 years is unprecedented in ~450ky
Modern record shows increasing NH source throughout century
Interhemispheric difference has been increasing
Seasonal Cycle is largest in NH
Atmospheric CO2
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Atmospheric CO2 at Mauna Loa Observatory
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0.0
0.5
1.0
1.5
2.0
2.5
3.0
1979 1984 1989 1994 1999 2004
10 Minor CFC11 CFC12 N2O CH4 CO2
Ra
dia
tiveF
orc
ing
(W
m-2
)
Radiative Forcing by Long-Lived Atmospheric Gases
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Global Atmospheric Watch (WMO/GAW) Monitoring Sites for CO2
Monitoring Stations for Carbon Dioxide (CO2)
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Courtesy of World Data Centre For Greenhouse Gases
http://gaw.kishou.go.jp/wdcgg.html
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Data-Driven Interpretive Analysis:Identifying Global Sources and Sinks
Oceanic Processes
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Column inventory of anthropogenic CO2 in the ocean (mol m2).
High inventories are associated with deep water formation in the North Atlantic and intermediate and mode water formation between 30° and 50°S.
Total inventory of shaded regions is 106 ± 17 Pg C. (From Sabine et al. 2004)
Ocean Carbon Inventory
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Sea-air exchange of carbon dioxide
Terrestrial Processes
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Terrestrial biosphere takes up approximately three billion tons of human emitted carbon dioxide per year
Carbon Dioxide Partitioning
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Average concentrations of CO2 in marine surface air indicate that the continent of North America could be a net sink of CO2.
Or is this a more “local” effect that is caused mainly by sources/sinks in the ocean basins?
part
s pe
r m
illio
n
CO2 in Air:North Atlantic minus North Pacific
Future
Directions
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US Effort—Climate Change Science Program (CCSP)
Guides and directs federal research efforts
Answers emerging climate science questions addresses key climate research challenges
Involves 13 Federal Agencies/Departments
Overseen by Ministerial/Cabinet-level officials
Operates on a ~$2B annual expenditure
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CCSP Strategic Plan(www.climatescience.gov)
Chapter 3: Atmospheric Composition
Chapter 7: Carbon Cycle
Chapter 12: Observing and Monitoring the Climate System
S&A Product 2.2: Will provide a synthesis and integration of the current knowledge of the North American carbon budget and its context within the global carbon cycle. In a format useful to decisionmakers
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International Efforts— GEOSS
Leadership in development and implementation of the Global Earth Observation System of Systems (GEOSS)
GCOS is a major contribution to GEOSS for climate observations
GEOSS supports integrated global observations of CO2 & related gases
Climate Technical Reference Document (USG document)
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Charles David Keeling1928—2005