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Open-File Report 2010–1144

Public Review Draft: A Method for Assessing Carbon Stocks, Carbon Sequestration, and Greenhouse-Gas Fluxes in Ecosystems of the United States Under Present Conditions and Future Scenarios

By Zhiliang Zhu (editor), Brian Bergamaschi, Richard Bernknopf, David Clow, Dennis Dye, Stephen Faulkner, William Forney, Robert Gleason, Todd Hawbaker, Jinxun Liu, Shuguang Liu, Stephen Prisley, Bradley Reed, Matthew Reeves, Matthew Rollins, Benjamin Sleeter, Terry Sohl, Sarah Stackpoole, Stephen Stehman, Robert Striegl, Anne Wein, and Zhiliang Zhu

This draft methodology is prepared in support of a national assessment of ecological carbon sequestration and greenhouse-gas fluxes, which is required by the Energy Independence and Security Act of 2007. Public comments are solicited in order to further improve the technical scope, methods, availability of relevant ecological data, and collaborations. To provide comments, please click here.


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The Energy Independence and Security Act of 2007 (EISA), Section 712, authorizes the U.S. Department of the Interior to develop a methodology and conduct an assessment of the Nation’s ecosystems focusing on carbon stocks, carbon sequestration, and emissions of three greenhouse gases (GHGs): carbon dioxide, methane, and nitrous oxide. The major requirements include (1) an assessment of all ecosystems (terrestrial systems, such as forests, croplands, wetlands, shrub and grasslands; and aquatic ecosystems, such as rivers, lakes, and estuaries), (2) an estimation of annual potential capacities of ecosystems to increase carbon sequestration and reduce net GHG emissions in the context of mitigation strategies (including management and restoration activities), and (3) an evaluation of the effects of controlling processes, such as climate change, land use and land cover, and wildlfires. The purpose of this draft methodology for public review is to propose a technical plan to conduct the assessment.

Within the methodology, the concepts of ecosystems, carbon pools, and GHG fluxes used for the assessment follow conventional definitions in use by major national and international assessment or inventory efforts. In order to estimate current ecosystem carbon stocks and GHG fluxes and to understand the potential capacity and effects of mitigation strategies, the method will use two time periods for the assessment: 2001 through 2010, which establishes a current ecosystem GHG baseline and will be used to validate the models; and 2011 through 2050, which will be used to assess future potential conditions based on a set of projected scenarios. The scenario framework is constructed using storylines of the Intergovernmental Panel on Climate Change (IPCC) Special Report Emission Scenarios (SRES), along with initial reference land-use and land-cover (LULC) and land-management scenarios. An additional three LULC and land-management mitigation scenarios will be constructed for each storyline to enhance carbon sequestration and reduce GHG fluxes in ecosystems. Input from regional experts and stakeholders will be solicited to construct realistic and meaningful scenarios.

The methods for mapping the current LULC and ecosystem disturbances will require the extensive use of both remote-sensing data and in-situ (for example, forest inventory data) to capture and characterize landscape-change events. For future potential LULC and ecosystem disturbances, key drivers such as socioeconomic, policy, and climate assumptions will be used in addition to biophysical data. The product of these analyses will be a series of maps for each future year for each scenario. These annual maps will form the basis for estimating carbon storage and GHG emissions. For terrestrial ecosystems, carbon storage, carbon-sequestration capacities, and GHG emissions under the current and projected future conditions will be assessed using the LULC and ecosystem-disturbance estimates in map format with a spatially explicit biogeochemical ensemble modeling system that incorporates properties of management activities (such as tillage or harvesting) and properties of individual ecosystems (such as elevation, vegetation characteristics, and soil attributes). For aquatic ecosystems, carbon burial in sediments and GHG fluxes are functions of the current and projected future stream flow and sediment transports, and therefore will be assessed using empirical modeling methods. Validation and uncertainty analysis methods described in the methodology will follow established guidelines to assess the quality of the assessment results.

The U.S. Environmental Protection Agency’s Level II ecoregions map (which delineates 24 ecoregions for the Nation) will be the practical instrument for developing and delivering assessment results. Consequently, the ecoregion will be the reporting unit of the assessment because the mitigation scenarios, assessment results, validation, and uncertainty analysis will be produced at this scale. The implementation of these methods will require collaborations among various Federal agencies, State agencies, nongovernmental organizations, and the science community. Using the method described in this document, the assessment can be completed in approximately three years. The primary deliverables will be tables, charts, and maps contained in assessment reports that will present the estimated GHG parameters annually for 2001 through 2050 by ecosystem, pool, and scenario. These results will permit the evaluation of a range of policies, mitigation options, and research topics, such as the demographic, LULC, or climate-change effects on carbon stocks, carbon sequestration, and GHG fluxes in ecosystems.

First posted July 2010

For additional information contact:
Zhiliang Zhu
U.S. Geological Survey
12201 Sunrise Valley Drive
Reston, VA 20192

Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.

Suggested citation:

Zhu, Zhiliang, ed., Bergamaschi, Brian, Bernknopf, Richard, Clow, David, Dye, Dennis, Faulkner, Stephen, Forney, William, Gleason, Robert, Hawbaker, Todd, Liu, Jinxun, Liu, Shuguang, Prisley, Stephen, Reed, Bradley, Reeves, Matthew, Rollins, Matthew, Sleeter, Benjamin, Sohl, Terry, Stackpoole, Sarah, Stehman, Stephen, Striegl, Robert, Wein, Anne, and Zhu, Zhiliang, 2010, Public review draft; A method for assessing carbon stocks, carbon sequestration, and greenhouse-gas fluxes in ecosystems of the United States under present conditions and future scenarios: U.S. Geological Survey Open-File Report 2010–1144, 195 p., available online at



Energy Independence and Security Act of 2007

Executive Summary

1. Introduction

1.1. Requirements of Section 712 of the Energy Independence and Security Act of 2007

1.2. Understanding the Concepts and Requirements of the Energy Independence and Security Act of 2007

1.2.1. Assessment

1.2.2. Ecosystems

1.2.3. Adaptation and Mitigation Strategies

1.2.4. Carbon-Sequestration Capacity

1.2.5. Processes That Control the Flux of Covered Greenhouse Gases

1.2.6. Management Activities and Restoration Activities

1.2.7. Range of Policies

1.2.8. Use of Native Plant Species

1.2.9. Measuring, Monitoring, and Quantifying

1.2.10. Use of Economic and Other Systems Models, Analyses, and Estimates

1.3. Summary

2. Review of Concepts and Literature

2.1. Major Carbon-Cycle Processes and Pools

2.2. Current Knowledge of the Carbon Cycle and Greenhouse Gas-Fluxes in the United States

2.3. Effects of Major Controlling Processes

2.3.1. Effects of Land-Use and Land-Cover Change and Land-Management Change

2.3.2. Effects of Ecosystem Disturbances

2.3.3. Effects of Climate Change, Elevated Carbon Dioxide, and Nitrogen Fertilization

2.4. Carbon Sequestration and Ecosystem Services

2.5. Ongoing Global and National Carbon and Greenhouse-Gas Inventories and Assessments

2.5.1. Intergovernmental Panel on Climate Change Scenarios and Guidelines

2.5.2. Examples of Continental-Scale Greenhouse-Gas Inventories and Assessments

2.5.3. Existing National-Scale Inventories and Assessments in the United States

2.5.4. Uncertainty Assessment and Reporting in Existing National Assessments

2.5.5. Economic Analysis and Its Use in Existing National Assessments

3. Methodology for the National Assessment

3.1. Introduction

3.1.1. Design Requirements and Goals for Assessment

3.1.2. Methodology Scope

3.1.3. Methodology Constraints

3.1.4. Collaborations for the Assessment

3.1.5. Methodology Organization

3.2. Methodology Framework

3.2.1. Framework for Assessing Current Carbon Stocks, Carbon Sequestration, and Greenhouse-Gas Fluxes

3.2.2. Framework for Assessing Future Potential Carbon Stocks, Carbon Sequestration, and Greenhouse-Gas Fluxes

3.2.3. Methodology Framework Summary

3.3. Introduction to Assessment Methods

3.3.1. Technical Plan for Key National Datasets

3.3.2. Land-Use and Land-Cover Change

3.3.3. Ecosystem Disturbances

3.3.4. Carbon Stocks, Carbon Sequestration, and Greenhouse-Gas Fluxes in Terrestrial Ecosystems

3.3.5. Carbon Sequestration and Greenhouse Gas Fluxes of Aquatic Ecosystems

3.3.6. Analyses of Assessment Results—Mitigation Activities, Ecosystem Services, Costs, and Benefits

3.3.7. Validation Methods

3.3.8. Methods for Assessing and Reporting Uncertainty

3.3.9. Requirements of Section 712 of the Energy Independence and Security Act for Measuring and Monitoring

3.4. Data Products, Deliverables, and Reports

3.4.1. Data Products

3.4.2. Assessment Reporting

4. Conducting the National Assessment

4.1. Operational Issues

4.2. Major Scientific Research and Development Needs

4.3. Intended Applications

References Cited


Appendix A. Reference and Alternative Mitigation Scenarios

Appendix B. Land-Use and Land-Cover Modeling

Appendix C. Characterization and Modeling of Major Ecosystem Disturbances

Appendix D. Methods for Assessing Carbon Stocks, Carbon Sequestration, and Greenhouse-Gas Fluxes of Terrestrial Ecosystems

Appendix E. Methods for Assessing Carbon Stocks, Carbon Sequestration, and Greenhouse-Gas Fluxes of Aquatic Ecosystems

Appendix F. Methods for Analyzing Ecosystem Services and Benefits and Costs of Mitigation Activities

Appendix G. Methods for Validation and Uncertainty Assessment

Appendix H. Methods for Energy Independence and Security Act Measuring and Monitoring Requirements

Appendix I. Data Management Technical Plan

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