Understanding, quantifying, and tracking atmospheric methane and emissions is essential for addressing concerns and informing decisions that affect the climate, economy, and human health and safety. Atmospheric methane is a potent greenhouse gas (GHG) that contributes to global warming. While carbon dioxide is by far the dominant cause of the rise in global average temperatures, methane also plays a significant role because it absorbs more energy per unit mass than carbon dioxide does, giving it a disproportionately large effect on global radiative forcing. In addition to contributing to climate change, methane also affects human health as a precursor to ozone pollution in the lower atmosphere.

Improving Characterization of Anthropogenic Methane Emissions in the United States summarizes the current state of understanding of methane emissions sources and the measurement approaches and evaluates opportunities for methodological and inventory development improvements. This report will inform future research agendas of various U.S. agencies, including NOAA, the EPA, the DOE, NASA, the U.S. Department of Agriculture (USDA), and the National Science Foundation (NSF).

Contents

• The National Academies of SCIENCES • ENGINEERING • MEDICINE
• COMMITTEE ON ANTHROPOGENIC METHANE EMISSIONS IN THE UNITED STATES: IMPROVING MEASUREMENT, MONITORING, PRESENTATION OF RESULTS, AND DEVELOPMENT OF INVENTORIES
• BOARD ON ATMOSPHERIC SCIENCES AND CLIMATE
• Acknowledgments
• Preface
• Summary
  • MEASUREMENT APPROACHES
  • INVENTORIES AND CURRENT U.S. METHANE EMISSIONS
  • MEETING THE CHALLENGES OF CHARACTERIZING METHANE EMISSIONS
• 1. Introduction
  • WHY MONITOR, MEASURE, AND TRACK ATMOSPHERIC METHANE AND METHANE EMISSIONS?
  • METHANE IN THE ATMOSPHERE
  • METHANE INVENTORIES
  • SOURCES OF METHANE EMISSIONS
  • METHANE EMISSION ESTIMATION: THE TOP-DOWN AND BOTTOM-UP METHODOLOGIES AND MODELS
  • THIS STUDY AND THE COMMITTEE’S APPROACH
  • REPORT ROADMAP
• 2. Current Inventories of Methane Emissions
  • INVENTORY OF U.S. GREENHOUSE GAS EMISSIONS AND SINKS
  • GREENHOUSE GAS REPORTING PROGRAM
  • STATE-LEVEL METHANE EMISSION INVENTORIES
  • GRIDDED METHANE INVENTORIES AND STUDIES
  • OVERVIEW OF METHANE EMISSIONS IN THE UNITED STATES FROM KEY SOURCE CATEGORIES
  • RECALCULATIONS IN THE GHGI
  • FUTURE U.S. METHANE EMISSIONS
• 3. Methane Emission Measurement and Monitoring Methods
  • BOTTOM-UP TECHNIQUES FOR MEASURING METHANE EMISSIONS
  • TOP-DOWN TECHNIQUES FOR MEASURING METHANE EMISSIONS
  • COMPARISON OF BOTTOM-UP AND TOP-DOWN APPROACHES
• 4. Addressing Uncertainties in Anthropogenic Methane Emissions
  • SOURCES OF UNCERTAINTIES IN THE BOTTOM-UP APPROACH
  • SOURCES OF UNCERTAINTIES IN THE TOP-DOWN APPROACH
  • EMISSION INVENTORY IMPROVEMENT STUDIES: DESIGN AND DATA ANALYSES
• 5. Presenting Methane Emission Data and Results
  • DESIGNING THE STUDY
  • REPORTING THE DATA TRANSPARENTLY
  • MAKING INPUT DATA PUBLICLY AVAILABLE
  • GUIDANCE ON INCORPORATING INFORMATION FROM NEW STUDIES INTO THE GHGI
• 6. Meeting the Challenges of Characterizing Methane Emissions
• References
• Glossary
• APPENDIXES
  • APPENDIX A. Acronyms and Abbreviations
  • APPENDIX B. Definition of U.S. Greenhouse Gas Inventory Categories
  • APPENDIX C. Other Anthropogenic Sources of Methane
  • APPENDIX D. U.S. Greenhouse Gas Inventory Development
  • APPENDIX E. Acknowledgment of Those Who Provided Input to the Committee
  • APPENDIX F. Common Units for Reporting Methane Concentrations and Emissions
  • APPENDIX G. Biographical Sketches of Committee Members
  • APPENDIX H. Disclosure of Conflict of Interest

Suggested citation:

National Academies of Sciences, Engineering, and Medicine. 2018. Improving Characterization of Anthropogenic Methane Emissions in the United States. Washington, DC: The National Academies Press. doi: https://doi.org/10.17226/24987.