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Updated 16 September 2008

The Global Carbon Cycle
USGCRP Program Element




The Global Carbon Cycle


Recent Accomplishments

Near-Term Plans

Archived News Postings [June 2000 - July 2005]

Related Sites

Calls for Proposals

CCSP / USGCRP Carbon Cycle Working Group Members

For long term plans, see Carbon Cycle chapter of the Strategic Plan for the Climate Change Science Program (2003) posted on CCSP web site


Carbon Cycle Science Home Page


The Carbon Cycle.  Basic background information from NASA's Earth Observatory Reference section.

Human Interactions with the Carbon Cycle. Summary of a Workshop.  
By Paul C. Stern for the  National Research Council,  Committee on the Human Dimensions of Global Change, Division of Behavioral and Social Sciences (Washington, DC: National Academy Press, 2002).

Forest2MRW2Increasing levels of atmospheric CO2 and methane are major drivers of climate change. The CCSP global carbon cycle element seeks to better quantify and understand the dynamics of the global carbon cycle that determine CO2 and methane fluxes and carbon storage in terrestrial and oceanic ecosystems. Carbon cycle processes depend on climate, thus linking carbon cycle and climate change analyses is critical. Carbon cycle research involves multiple disciplines and extends over a broad range of spatial and temporal scales. Major multi-agency activities include the North American Carbon Program (NACP), an effort to describe and reduce uncertainties about the North American carbon budget and underlying processes, and the Ocean Carbon and Climate Change (OCCC) Program, a research effort aimed at determining how climate change will affect the future behavior of the oceanic carbon sink. In FY 2009, NACP will address key gaps and uncertainties in the carbon syntheses developed previously, and aspects of the OCCC and NACP will be coordinated to better quantify and understand the roles of adjacent ocean basins in the North American carbon budget. NASA will launch the Orbiting Carbon Observatory (OCO) to provide, for the first time, consistent atmospheric carbon observations globally from space, and carbon data assimilation systems will begin to derive estimates of carbon sources and sinks from these measurements.

See the Carbon Cycle Science Plan
For additional information on the Carbon Cycle Initiative, contact the Carbon Cycle Interagency Working Group's Program Office


Strategic Research Questions

7.1. What are the magnitudes and distributions of North American carbon sources and sinks on seasonal to centennial time scales, and what are the processes controlling their dynamics?

7.2. What are the magnitudes and distributions of ocean carbon sources and sinks on seasonal to centennial time scales, and what are the processes controlling their dynamics?

7.3.  What are the effects on carbon sources and sinks of past, present, and future land-use change and resource management practices at local, regional, and global scales?

7.4. How do global terrestrial, oceanic, and atmospheric carbon sources and sinks change on seasonal to centennial timescales, and how can this knowledge be integrated to quantify and explain annual global carbon budgets?

7.5.  What will be the future atmospheric concentrations of carbon dioxide, methane, and other carbon-containing greenhouse gases, and how will terrestrial and marine carbon sources and sinks change in the future?

7.6.  How will the Earth system, and its different components, respond to various options for managing carbon in the environment, and what scientific information is needed for evaluating these options?

See Strategic Plan for the U.S. Climate Change Science Program, Chapter 7, for detailed discussion of these research questions.

The U.S. Carbon Cycle Science Program is making progress in understanding the changes, magnitudes, and distributions of carbon sources and sinks, the processes operating within and between major terrestrial, oceanic, and atmospheric carbon reservoirs, and the underlying mechanisms involved, including human activities, fossil fuel emissions, land use, and climate forcings. Program scientists are currently quantifying many of the intricate complexities and interactions between the major carbon reservoirs and climate. To execute this undertaking, Federal agencies and departments with carbon cycle interests coordinate, manage, and support the overall science and implementation plans under two major thrusts: North American Carbon Program (NACP) and Ocean Carbon and Climate Change (OCCC) Program. As these science programs mature and generate needed carbon observations, field and experimental results are being used to constrain advanced carbon models at scales from experimental sites to regions as an important means of incorporating site, regional, and global observations into global carbon models and analyses. The ultimate objective is to develop increasingly realistic and predictive coupled carbon-climate and Earth system models to provide better insight into future feedbacks and drivers between the major components of the Earth system.


The U.S. Carbon Cycle Science Program contributes to all goals of the CCSP Strategic Plan (2003)—focusing particularly on Goal 2, “Improved quantification of the forces bringing about changes in the Earth’s climate and related systems.” The program addresses directly the six overarching carbon cycle questions of Chapter 7 of the CCSP Strategic Plan. The research element is synergistic with the Ecosystems, Global Water Cycle, Climate Variability and Change, Atmospheric Composition, Land-Use and Land-Cover Change, and Human Contributions and Responses research elements. The agencies responsible for carbon cycle research are DOE; NASA; NIST; NOAA; NSF; USDA’s Agricultural Research Service (ARS), Cooperative State Research, Education, and Extension Service (CSREES), Forest Service, and Natural Resources Conservation Service (NRCS); and USGS. Together, they have planned and are coordinating a multidisciplinary research strategy to integrate the broad range of needed infrastructure and resources, scientific expertise, and stakeholder input essential for program success and improved decision processes.

In FY 2009, a new CCSPwide research priority will be initiated to quantify the magnitude and dynamics of carbon cycling of high-latitude ecosystems under abrupt climate change. In support of this research initiative, the U.S. Carbon Cycle Science Program will coordinate a concerted Federal effort addressing high-latitude carbon cycle research (observations, attribution, prediction, and mitigation), which will be conducted in unison with its priorities under the NACP and OCCC programs. To accomplish the carbon cycle element of the new CCSP priority at high latitudes, the interagency working group will solicit new investments and reprogram previous research investments to complement current research in order to fill gaps, and promote and augment ongoing carbon observations and networks in high-latitude lands and ocean ecosystems. The enhanced emphasis on high-latitude ecosystems will provide critical scientific information on past and current carbon dynamics of undersampled regions of North America and adjacent oceans, as well as other undersampled regions of the world, such as Antarctica and the adjacent Southern Ocean.

alaska gold project


NACP is designed to address strategic research question 7.1, and elements of questions 7.2 through 7.6, in Chapter 7 of the CCSP Strategic Plan. For example, it will quantify the magnitudes and distributions of terrestrial, freshwater, oceanic, and atmospheric carbon sources and sinks for North America and adjacent coastal oceans; enhance understanding of the processes controlling source and sink dynamics; and produce consistent analyses of North America’s carbon budget that explain regional and continental contributions and year-toyear variability. This program is committed to reducing uncertainties related to the increase of carbon dioxide and methane in the atmosphere and the amount of carbon, including the fraction of fossil fuel carbon, being taken up by North America’s ecosystems and adjacent coastal oceans.

As research programs mature, scientific and governmental collaborations on carbon cycle science are broadening and escalating with international neighbors within North America as well as with extended Northern Hemisphere interests, international organizations, and global partners.


OCCC is designed to address strategic research question 7.2, and elements of questions 7.3 through 7.6, in Chapter 7 of the CCSP Strategic Plan. For example, in regards to question 7.2, it will focus on oceanic research aimed at quantifying how much atmospheric carbon dioxide is being taken up by the ocean at the present time and how climate change will affect the future behavior of the oceanic carbon sink. The terrestrial and ocean carbon programs are synergistic, integrating program activities addressing carbon dynamics on the coastal shelves adjacent to North America (questions 7.1 and 7.2), where carbon changes in the terrestrial system greatly influence carbon processes in the coastal ocean.


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