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Date:  March 19, 2010

Contacts:  Sara Frueh, Media Relations Officer

Jennifer Walsh, Media Relations Officer

Luwam Yeibio, Media Relations Assistant

Office of News and Public Information

202-334-2138; e-mail <>




Better Estimates of Greenhouse Gas Emissions Needed to Monitor, Verify International Climate Treaties;

Strategic Investments Could Improve Reporting Within Five Years


WASHINGTON -- Countries can inventory their carbon dioxide emissions from fossil-fuel use accurately enough to support monitoring of an international climate change treaty, but currently there is no sufficiently accurate way to verify countries' self-reported estimates using independent data, such as atmospheric measurements, says a new report from the National Research Council.  Strategic investments could be made that within five years would both improve self-reporting and yield a useful way to verify these estimates, reducing uncertainties about carbon dioxide emissions from fossil-fuel use and deforestation to less than 10 percent, said the committee that wrote the report.  


Agreements to limit emissions of greenhouse gases are currently the focus of international negotiations, and with such accords will come the need to accurately estimate these emissions and monitor their changes over time.  "For any international agreement to limit greenhouse gas emissions, it would be essential for each country to monitor its own emissions and to provide a transparent capability for any nation to check the values reported by another," said Stephen Pacala, chair of the committee that wrote the report and the Frederick D. Petrie Professor of Ecology and Evolutionary Biology at Princeton University, Princeton, N.J.  "This would give nations confidence that their neighbors are living up to their commitments."


Under the United Nations Framework Convention on Climate Change (UNFCCC), countries are currently required to estimate their greenhouse gas emissions by identifying human activities that cause emissions, and then multiplying each activity by its rate of emissions.  The level of uncertainty in these self-reported estimates depends on each country's institutional and technical capabilities, the report notes.  In many developed countries, for example, uncertainties are reported to be less than approximately 5 percent for carbon dioxide emissions from fossil-fuel use.  


The committee focused on carbon dioxide because it is the largest single contributor to global climate change and is thus the focus of many mitigation efforts.  Estimates of emissions of greenhouse gases other than carbon dioxide are likely to remain relatively uncertain, the report says.


Because UNFCCC procedures have broad international support and can estimate carbon dioxide emissions from fossil fuels with reasonable accuracy, they will likely continue to be the primary way to monitor emissions under any new climate treaty, the report notes.  But the reporting system has shortcomings, the committee found.  Developing countries do not provide regular, detailed emissions reports, for example, and independent data to check self-reported emissions is limited.  In addition, there are large uncertainties in estimates of the carbon dioxide and other greenhouse gases released into or removed from the atmosphere because of changes in land use, such as deforestation or reforestation. 


The report recommends ways to overcome these weaknesses, listing methods that could improve both self-reported estimates and other nations' ability to verify them.  Regular, rigorous reporting and review should be extended to all countries, said the committee.  And the most stringent and accurate methods for calculating greenhouse gas emissions should be used for the largest emissions sources in each country, which in some cases may be deforestation and agriculture rather than fossil-fuel use. 


Financial and technical assistance will be required for developing countries to build an ongoing capacity to collect, analyze, and report emissions information regularly, the report says.  Significant improvements in the accuracy of the inventories from 10 of the highest-emitting developing countries, such as China and India, could be achieved for approximately $11 million over five years, according to the committee. 


Enabling independent verification of countries' self-reported estimates will require additional atmospheric measurements and improved models to predict the movement of greenhouse gases in the atmosphere, the report says.  It recommends that new monitoring stations be established near cities and other large local emissions sources.  In addition, NASA should build and launch a replacement for the Orbiting Carbon Observatory, which failed at launch in February 2009.  Such an observatory could monitor carbon dioxide emissions from cities and power plants and attribute them to individual countries; no other satellite has its critical combination of abilities, including high precision, a small footprint, and an ability to sense carbon dioxide near Earth's surface. 


Using improved methods, fossil-fuel carbon dioxide emissions could be estimated by each country and checked using independent information with less than 10 percent uncertainty, the report says. The same is true for satellite-based estimates of deforestation, which is the largest source of carbon dioxide emissions next to fossil-fuel use, and for growth of new forests, which is an important "sink" for reducing carbon dioxide.


To aid efforts to understand how greenhouse gases are affected by land use, a working group should be established to produce publicly available global maps of land use and land cover change at least every two years, using Landsat and high-resolution satellite imagery.  In addition, an interagency group with broad participation from the research community should design a program to improve ways to estimate how agriculture, forestry, and other land uses affect emissions of carbon dioxide, nitrous oxide, and methane. 


The report adds that the isotope carbon-14 should be measured in the carbon dioxide already collected at atmospheric sampling stations.  Carbon-14 is present in living organisms but not in fossil fuels, so it provides a way to discern whether carbon dioxide is generated from fossil-fuel or non-fossil-fuel sources.  These measurements could be made by the National Oceanic and Atmospheric Administration, a national laboratory, or a university at a cost of approximately $5 million to $10 million per year.


The National Research Council is the operating arm of the National Academy of Sciences and National Academy of Engineering.  They are independent, nonprofit institutions that provide science, technology, and health policy advice under an 1863 congressional charter.  Committee members, who serve pro bono as volunteers, are chosen for each study based on their expertise and experience and must satisfy conflict-of-interest standards.  The resulting consensus reports undergo external peer review before completion.  For more information, visit A committee roster follows.



Copies of Verifying Greenhouse Gas Emissions: Methods to Support International Climate Agreements are available from the National Academies Press; tel. 202-334-3313 or 1-800-624-6242 or on the Internet at Reporters may obtain a copy from the Office of News and Public Information (contacts listed above). 


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[ This news release and report are available at ]



Division on Earth and Life Studies

Board on Atmospheric Sciences and Climate


Committee on Methods for Estimating Greenhouse Gas Emissions


Stephen W. Pacala* (chair)

Frederick D. Petrie Professor of Ecology and Evolutionary Biology, and


Princeton Environmental Institute

Princeton University

Princeton, N.J.


Clare Breidenich

Independent Consultant



Peter G. Brewer

Senior Scientist

Monterey Bay Aquarium Research Institute

Moss Landing, Calif.


Inez Y. Fung*

Professor of Atmospheric Science, and


Berkeley Institute of the Environment

University of California



Michael R. Gunson

Chief Scientist

Earth Science and Technology Directorate

Jet Propulsion Laboratory

Pasadena, Calif.


Gemma Heddle

Carbon Management Adviser

Chevron Corp.

San Ramon, Calif.


Beverly E. Law

Professor of Global Change Forest Science

Oregon State University



Gregg Marland

Senior Staff Scientist

Environmental Science Division

Oak Ridge National Laboratory

Oak Ridge, Tenn.


Keith Paustian

Professor of Soil Ecology

Department of Soil and Crop Sciences, and

Senior Research Scientist

Natural Resources Ecology Laboratory

Colorado State University

Fort Collins


Michael J. Prather

Fred Kavli Chair and Professor

Department of Earth System Sciences

University of California



James T. Randerson


Department of Earth System Science

University of California



Pieter P. Tans

Senior Scientist

Earth System Research Laboratory

National Oceanic and Atmospheric Administration

Boulder, Colo.


Steven C. Wofsy

Abbott Lawrence Rotch Professor of Atmospheric and Environmental Sciences

Department of Earth and Planetary Sciences

Harvard University

Cambridge, Mass.




Anne Linn

Study Director


*Member, National Academy of Sciences