Climate Change: Selected Nations' Reports on Greenhouse Gas Emissions Varied in Their Adherence to Standards
Published: 2003-12-23T00:00:00

Fast Facts:

Highlights:
section_title: Why GAO Did This Study
paragraphs: In 1992, the United States and other parties, including both developed and developing nations, agreed to try to limit dangerous human interference with the climate by participating in the United Nations Framework Convention on Climate Change. The parties agreed, among other things, to report on their emissions of carbon dioxide and five other gases whose buildup in the atmosphere is believed to affect the climate. The parties developed standards for these reports and processes for periodically evaluating the reports. Expert teams selected by the parties review the developed nations' reports; staff of the Framework Convention's administrative arm (the Secretariat) assess developing nations' reports. GAO agreed to describe the results of the most recent reviews and assessments of reports from selected economically developed and developing nations, as well as the parties' plans to improve the reports. For the developed nations, GAO agreed to study four geographically dispersed nations with high levels of emissions--Germany, Japan, the United Kingdom, and the United States. For the developing nations, GAO studied China, India, and Mexico, which also have high emissions levels and are geographically dispersed. These nations are not representative of others; therefore, GAO's findings cannot be generalized.
section_title: What GAO Found
paragraphs: In their most recent reviews, expert teams found that the United Kingdom's 2000 and 2002 reports on greenhouse gas emissions and the United States's 2000 report were largely complete, although the teams noted minor findings, such as the lack of information on quality assurance methods, which the nations were encouraged, but not required, to include in their submissions. In contrast, they found that Germany's 2001 and Japan's 2000 reports lacked critical elements, such as the required documentation that was essential to understanding them. Preliminary checks found that all four nations' 2003 reports were largely complete. Secretariat staff have not assessed inventories from China and India because these nations have not submitted them. According to Secretariat records, China and India plan to submit inventories in February 2004 and November 2003, respectively. Secretariat staff assessed Mexico's most recent inventory, but they reported few details about it because their policy is to consolidate the findings of all the developing nations' inventories submitted during a year. To improve the inventories, the parties are changing the reporting standards and review process. For example, starting in 2004, developed nations must present their inventory reports in a standardized format to facilitate review, and developing nations must report data for more years and gases than before. Also, in 2003, the parties began conducting more rigorous reviews of developed nations' inventories, but no such changes for developing nations are planned.

section_title: Letter
paragraphs: The Congress recently debated the need to limit U.S. emissions of the so- called “greenhouse gases”—whose buildup in the atmosphere is widely  believed to adversely affect the climate. This debate dates back to at least  1992, when the United States and most of the other nations of the world  took steps toward ensuring that worldwide progress in reducing  greenhouse gas emissions could eventually be measured. At that time, the  nations negotiated the United Nations Framework Convention on Climate  Change (hereafter called the Framework Convention) with the aim of  stabilizing atmospheric concentrations of carbon dioxide and five other  greenhouse gases.  The nations also agreed to periodically report on their  greenhouse gas emissions.
As of November 2003, 188 parties had ratified the Framework Convention,  including the United States. Of this total, 40 parties—39 nations and the  European Union as a whole—are listed in Annex I of the convention. The  39 Annex I nations include the economically developed nations of the  world as well as nations whose economies are in transition, including the  Russian Federation, the Baltic states, and several central and eastern  European nations. The Annex I nations have agreed to report annually on  their emissions levels. The annual reports, called inventories, generally  reflect estimated—rather than directly measured—data. The remaining 148  nations that are party to the Framework Convention but are not included in  Annex I—“non-Annex I nations”—are generally classified as economically  developing nations. These nations also agreed to report on their emissions,  but in less detail and less frequently than the Annex I nations.
Recognizing that good-quality data on all nations’ greenhouse gas  emissions are critical to determining whether the Framework Convention  is successful at stabilizing greenhouse gas emissions worldwide, the parties  to the convention are working in several ways to ensure the quality of the  emissions data that nations report. First, with technical assistance from the  Intergovernmental Panel on Climate Change (IPCC), the parties developed  extensive procedures for all nations to follow when estimating and  reporting their greenhouse gas emissions and removals (removals offset  emissions—for example, forests absorb carbon dioxide, removing it from  the air). In addition, the developed Annex I nations agreed to provide funds  to help the non-Annex I nations develop their inventories. Finally, the  parties agreed that nations’ estimates of their emissions, and the  documentation that supports these estimates, would undergo one of two  main types of review:  one for Annex I nations and another for non-Annex I  nations.  Annex I nations’ inventories periodically undergo individual  reviews performed by teams of experts assembled from the party nations.  The expert reviews are extensive, examining all aspects of each inventory  and its preparation to determine whether the inventory complied with the  estimating and reporting procedures. The Framework Convention’s  administrative arm, the Secretariat, publishes a report on the findings of  each nation’s individual expert review. Non-Annex I nations’ inventories are  assessed by Secretariat staff, who examine all such inventories submitted  during the year. The assessment is less extensive and evaluative than the  review of Annex I nations’ submissions. It focuses on identifying problems  that the developing nations have had with preparing and reporting their  inventories and ways to improve them. The Secretariat issues one report  each year discussing its findings on the non-Annex I nations’ inventories in  summary format, with few nation-specific details.
We agreed with your offices to (1) describe the results of the most recent  expert reviews of the greenhouse gas inventories submitted by four  economically developed nations—Germany, Japan, the United Kingdom,  and the United States; (2) describe the results of any assessments of the  inventories of three developing nations—China, India, and Mexico; (3)  determine the extent to which the developed nations have confidence in  the quality of their inventory data, and describe any changes that the  parties to the Framework Convention have made to requirements for  assessing data confidence in the future; and (4) describe any steps that the  parties to the Framework Convention are taking as a group to improve the  quality of future inventories, including when such improvements might be  in place.
Also as agreed with your offices, in examining these issues, we did not  independently review the nations’ inventories to assess their quality.  Instead, we examined the guidance developed for the nations and the  requirements they are to meet in preparing and reporting their greenhouse  gas inventories and believe the guidance provides reasonable parameters  for ensuring good-quality inventory data. We also examined the  methodology for the reviews of developed nations’ inventories and believe  it provides reasonable help to reviewers in evaluating the quality of  inventories. We relied on the findings of the reviews as reported by the  Secretariat. Regarding the Annex I nations, we agreed to study the two  European Union nations and the two non-European Union nations with the  highest levels of emissions that are developed nations, according to the  most recent data available to the United Nations (2001). Although some  nations that are considered Annex I nations have economies in transition  and emit significant levels of greenhouse gases, as agreed, we did not  include them in our study. Regarding the non-Annex I nations—developing  nations—we agreed to study China, India, and Mexico because of their high  levels of greenhouse gas emissions and geographic dispersion. These seven  nations are not necessarily representative of other parties to the  Framework Convention; accordingly, our findings are not generalizable to  the other parties. Although we spoke with U.S. officials who are  responsible for assembling and managing the U.S. inventory, we did not  speak with comparable officials in the other six nations. It is our policy to  contact foreign government officials through the U.S. Department of State,  and we asked the department to facilitate that contact; however, the  department did not arrange for those contacts during our review. State  Department officials asserted that issues of reporting and review under the  Framework Convention have been particularly sensitive for the developing  nations; also, foreign governments might not readily grasp the different  roles of the General Accounting Office and the State Department. As a  result, according to State Department officials, some governments might  view a request of this nature from the United States as intrusive, raising  suspicions about the underlying purpose of such a study.
subsections: section_title: Background
paragraphs: Scientists have discovered that changes in the earth’s climate are induced  by the increasing concentrations of certain gases in the earth’s  atmosphere—some naturally occurring, others human-induced—that have  the potential to significantly alter the planet’s heat and radiation balance.  These so-called “greenhouse gases” trap some of the sun’s energy and  prevent it from returning to space. The trapped energy warms the earth’s  climate, much like glass in a greenhouse. Over the past century, humans  have contributed to the greenhouse effect, particularly by burning fossil  fuels, which increased atmospheric carbon dioxide and other greenhouse  gases. The effects of a warmer climate could have important consequences  for human health and welfare by, among other things, altering weather  patterns, changing crop yields, and leading to the flooding of coastal areas.
According to the Department of Energy’s Energy Information  Administration (EIA), in 2001, the most recent year for which data are  available, the United States and other developed nations accounted for just  under half (47 percent) of the world’s emissions of carbon dioxide—the  most prevalent greenhouse gas. The other emissions came from  economically developing nations, including China, India, and Mexico (40  percent), and from nations with economies in transition (13 percent) in  Europe and the Former Soviet Union. EIA projects that, over the next 2  decades, carbon dioxide emissions from each of the three nation groups  will increase; however, carbon dioxide emissions from developing nations  will increase most dramatically, surpassing those of developed nations by  2015, as shown in figure 1.
More specifically, figure 2 shows actual and projected carbon dioxide  emissions for the seven nations in our study. Growth in emissions between  2001 and 2025 is projected to range from 29 million metric tons for the  United Kingdom to 1,012 for China.
The seven nations in our study also differ greatly in terms of their  population and per capita income (an indicator of economic development).  For example, population ranged from about 60 million in the United  Kingdom to nearly 1.3 billion in China, and per capita income ranged from  $2,540 in India to $36,300 in the United States. (See table 1.)
Under the Framework Convention, the United States and the other parties  generally agreed to implement policies and measures aimed at returning  “individually or jointly to their 1990 levels these anthropogenic [human- caused] emissions” of greenhouse gases not covered by another treaty, the  Montreal Protocol. The six primary gases covered by the Framework  Convention are carbon dioxide, nitrous oxide, methane, and three  synthetic gases—sulfur hexafluoride, hydrofluorocarbons, and  perfluorocarbons. Emissions of these gases are generally not measured  because doing so would be too costly; consequently, they must be  estimated. In this regard, the IPCC, at the parties’ request, developed  detailed guidance on methodologies for nations to use when estimating  their emissions and revised that guidance twice, most recently in 1999.  Both developed and developing nations are required to follow this  guidance—Revised 1996 IPCC Guidelines for National Greenhouse Gas  Inventories—when preparing their inventories. In addition, in 2000, the  IPCC published—also at the parties’ request—its Good Practice Guidance  and Uncertainty Management in National Greenhouse Gas Inventories,  which contains information on prioritizing tasks to arrive at the best  possible estimates using finite resources as well as advice on establishing  quality assurance programs, among other things. The nations have been  encouraged, but not required, to follow the good practice guidance.
The parties to the Framework Convention also agreed to report  periodically to the Secretariat on their levels of greenhouse gas emissions.  For Annex I nations, those reports are extensive. Annually, each Annex I  nation is required to submit inventory data—in a common reporting format  the parties themselves agreed to—as well as a national inventory report  that explains how the data in the common reporting format were derived.  The common reporting format calls for data for each of the six emissions  sectors—energy, industrial processes, solvent and other product use,  agriculture, land-use change and forestry, and waste—as well as for the  data on the major sources that contribute to emissions from each sector.  The inventory data are to reflect a nation’s most recent reporting year as  well as all previous years back to the base year, which is 1990. For each  year, the common reporting format calls for 42 tables containing over 8,100  items that are sector-specific numbers; data summarized across sectors;  and other information, such as trends from the base year to the current  reporting year, recalculations of prior years’ data, and reasons certain  emissions were not estimated.  The parties require that data be submitted  in the common reporting format to facilitate comparison across nations  and to make it easier to review the data. Because an inventory contains  data from the base year to the most recent reporting year, each year’s  submission is larger than the last. The 2003 reporting format called for  approximately 98,000 items of inventory data and other information from  1990 through 2001.
The national inventory report, the second component of the submission,  should be detailed and complete enough to enable reviewers to understand  and evaluate the inventory. The report should include, among other things,  descriptions of the methods used to estimate the data, the rationale for  selecting the methods used, and information about the complexity of  methods and the resulting precision of the estimates; information on  quality assurance procedures used; discussion of any recalculations  affecting previously submitted inventory data; and information on  improvements planned for future inventories.
Each year, when Secretariat staff receive Annex I nations’ submissions,  they perform an initial check to determine whether the submissions are  complete and then synthesize the information to facilitate comparison  across nations. Teams of expert reviewers—comprising members chosen  by the parties for their sector expertise as well as to achieve broad  geographic representation—also use this synthesized information to  identify issues requiring clarification during their reviews of individual  submissions.
From 2000 through 2002, the parties tested the usefulness of three methods  of conducting expert reviews on selected submissions from Annex I  nations. The first type of review, called a desk review, consists of about 10  experts spending about 4 weeks in their respective nations reviewing  information on the same three nations’ inventories. For this type of review,  the experts communicate with each other and the nation being reviewed  via the Internet and telephone. The second type of review, called a  centralized review, involves about 10 experts spending about a week at the  Secretariat’s headquarters in Bonn, Germany, jointly reviewing between  four and six nations’ inventories. The third review type, called an in- country review, consists of a team of about 5 experts spending a week in  the nation whose inventory is being reviewed, jointly examining the  nation’s inventory and supporting information. The Secretariat chose  inventories of different levels of completeness to undergo desk and  centralized reviews; only nations that volunteered for an in-country review  received one.
During the 3-year test period, the experts examined the data and  supporting information the nations used to prepare the inventories via all  three types of reviews. For example, the experts determined whether a  nation calculated its emissions estimates using formulas from published  data sources or formulas specified by the parties. The experts also verified  the information provided in response to questions raised in previous  reviews. Finally, the experts summarized the inventories' strengths and  weaknesses; made recommendations for improvement, if warranted; and  presented their findings in reports that were both published and posted on  the Internet.
For Annex I nations’ submissions to be reviewed by the experts, the  submissions must meet two criteria. Since 2000, the experts have reviewed  only submissions that presented their data in the common reporting  format, and, beginning with the 2003 submissions, the experts will review  only submissions that include the national inventory report. According to  the parties to the Framework Convention, the goal of the expert reviews is  to identify areas in the inventories needing improvement; for this reason,  the experts’ reports do not rate the overall quality of the submissions, and  the reports do not identify some findings as being more important than  others. According to the Secretariat, since 1998, Annex I nations’  submissions have steadily and substantially improved in their timeliness  and completeness, and the expert review process has contributed to the  improved quality of recent submissions.
Non-Annex I nations’ requirements for format and frequency of reporting  differ from those for Annex I nations. Although all parties to the  Framework Convention are to develop their inventories using the revised  1996 IPCC guidelines and submit the inventories to the Secretariat, non- Annex I nations’ inventories are not stand-alone documents. Rather, a non- Annex I nation’s inventory is a component of its national communication,  which is a report it must submit to the Secretariat that discusses all of the  steps the nation is taking or plans to take to implement the Framework  Convention. In addition, non-Annex I nations are not required to use the  common reporting format or to submit a national inventory report.  Moreover, non-Annex I nations are not required to submit an inventory  each year but may instead negotiate the frequency of their submissions. To  date, most non-Annex I nations negotiated a deadline for only one  inventory. To help the non-Annex I nations develop and report their  inventories, the developed nations of Annex I provide financial assistance  that is disbursed through the convention’s financial mechanism, the Global  Environment Facility. The facility, which funds various types of  environmental projects in developing nations, disburses the funds,  including those to assist non-Annex I nations with their emissions  reporting, through implementing agencies, such as the United Nations  Development Program. The implementing agencies, in turn, disburse the  funds to the nations on a schedule and according to terms negotiated by the  agency and each nation.
The inventory reviews and the extent to which the results are reported also  differ for Annex I and non-Annex I nations. Reviews of Annex I nations’  submissions focus on compliance with reporting standards, and the results  are made publicly available in considerable detail. In contrast, because  non-Annex I nations are generally in the early stages of developing their  inventories and have limited resources to do so, assessments of their  submissions, and the resulting reports, focus largely on providing a forum  for the non-Annex I nations to exchange information on common reporting  problems and best practices. Consequently, while the Secretariat makes  reports on the results of non-Annex I assessments publicly available, it  does so in summary format and provides only a few nation-specific details  in tables that accompany the aggregated reports.
section_title: Recent Reviews Found That U.K. and U.S. Inventories Were Largely Complete, but German and Japanese Inventories Lacked Critical Elements
paragraphs: The most recent expert reviews of inventories submitted by the four  developed nations found that the U.K. and U.S. inventories contained most  of the required elements, but the German and Japanese inventories were  missing certain critical elements. Experts reviewed inventories variously  submitted from 2000 through 2002 by each of the four developed nations in  our study. The inventories submitted by Japan and Germany in 2000 and  2001, respectively, each received a centralized review. Two U.K. inventories  were reviewed: the one submitted in 2000 received an in-country review,  and the one submitted in 2002 received a desk review. The inventory that  the United States submitted in 2000 received both an in-country review and  a desk review. Although the experts planned to conduct reviews of all  Annex I nations’ inventories submitted in 2003, no results were available at  the time of our study.
The reviews of the submissions of the United Kingdom and the United  States found they were largely complete and noted only relatively minor  problems. For example, the reviews of the two nations’ 2000 submissions  noted that neither submission included information on quality assurance  procedures. Although the good practice guidance calls for including such  information in the national inventory report, the nations were encouraged,  but not required, to follow the good practice guidance for the 2000  submissions. Nonetheless, the experts included the lack of quality  assurance documentation as a finding of the reviews. Because the  problems noted were relatively minor, the suggestions for improving future  submissions constituted refinements rather than recommendations for  large-scale changes. For example, the experts’ report on the 2000 U.K.  submission suggested archiving the documentation supporting the national  inventory report in one location or on the Web. Similarly, the report on the  desk review of the 2000 U.S. submission suggested that more details on the  methods and factors used to estimate emissions for the land-use change  and forestry sector would allow more complete assessment of that sector’s  data.
In contrast, the reviews of the German and Japanese submissions found  them to be missing some critical components, and the experts’ reports  made suggestions for improvement that were fundamental in nature. For  example, the review of Germany’s 2001 submission found it contained only  summary-level and trend data; it did not include any of the sector-specific  data tables or recalculations of prior years’ data called for by the common  reporting format. Furthermore, the national inventory report was missing,  so the reviewers could not determine whether problems noted in previous  inventories had been addressed. Although the review of the Japanese 2000  submission found most of the data required by the common reporting  format was included, like the German submission, this one lacked the  national inventory report. As a result of these shortcomings, the experts  suggested that Germany submit a complete set of data for all of the  required years and sectors and that both nations submit the national  inventory report. Additional details on the findings of the six expert  reviews are contained in appendix I.
Although none of the four Annex I nations’ latest submissions—for 2003— had undergone an expert review as of November 2003, Secretariat staff had  performed initial completeness checks on each of them. They found that all  four nations’ submissions contained most of the required data as well as  the required national inventory reports.
section_title: Little Nation-Specific Inventory Information Is Available for the Three Developing Nations
paragraphs: The Secretariat has not assessed any inventories from China and India  because, as of November 2003, neither nation had submitted one. The  Secretariat assessed Mexico’s 2001 submission, but the Secretariat’s  practice is to issue one report on the findings of its assessments of all the  inventories submitted during the year, with few nation-specific details.  Therefore, the Secretariat made public little information about the results  of its assessments that could be directly tied to Mexico.
According to the Secretariat, China and India are preparing their initial  inventories, to be submitted as part of their first national communications.  Under article 12, paragraph 5, of the Framework Convention, non-Annex I  nations’ first inventories are due to the Secretariat “within three years of  the entry into force of the Framework Convention or of the availability of  financial resources” from the developed nations in Annex I. According to  the Secretariat, funding was approved for China in May 2000 and for India  in December 1999, and the first disbursements of funds took place in  November 2001 for China and in July 2001 for India. According to the  Secretariat, the due dates for their first greenhouse gas inventories are no  later than November 2004 for China and July 2004 for India.
Mexico submitted inventories in 1997 and 2001.  Although 106 developing  nations had submitted their initial inventories as of November 2003,  Mexico is the only nation to have submitted more than one. Secretariat  staff assessed Mexico’s 2001 inventory, along with those of 51 other non- Annex I nations that submitted inventories that year. In keeping with its  practice of reporting on its assessments of non-Annex I nations’ inventories  as a group, the report for 2001 contained only limited details that could be  linked specifically to Mexico’s inventory.  In particular, the Secretariat  reported that Mexico had improved its estimates of emissions from the  energy, agriculture, and land-use change and forestry sectors. It also  reported that Mexico could further improve its inventory by establishing  systematic procedures for preparing the inventory annually and by  including estimates for the solvent-use sector. Otherwise, the Secretariat  reported only generally on the results of the assessments of submissions of  the 52 non-Annex I nations’ inventories.
Mexico’s 2001 submission contained estimates for 1994, 1996, and 1998.  According to an EPA official who is knowledgeable about Mexico’s  inventory, the 2001 Mexico inventory is of reasonably high quality,  especially considering the limited resources Mexico has dedicated to  developing it. According to its submission, Mexico followed the IPCC  estimating guidelines and good practice guidance in preparing the  inventory. The EPA official further commented that Mexico’s 2001  submission is among the best of those of the developing nations, and in  some cases—for example, in presentation of its carbon dioxide emissions  data—is equal to those of some developed nations. On the other hand,  according to that official, Mexico did not (1) comply with the IPCC  estimating guidelines in developing the land-use change and forestry sector  data, (2) adequately estimate data for the three synthetic gases, or (3)  provide adequate documentation explaining the inventory. Furthermore,  Mexico developed its two inventories independent of each other, without  establishing a process that would systematically make documentation and  data additions and revisions as needed. Consequently, in the opinion of the  EPA official, it was difficult for Mexico to build upon its previous efforts  when preparing its second inventory.
section_title: The Four Developed Nations Reported Generally High Confidence in Their Latest Emissions Data, but Future Assessments of Confidence Must Be More Precise
paragraphs: As required for the 2003 submissions, the four developed nations  categorized their confidence in their emissions data as either high, medium,  or low. All four nations reported their confidence in the data as generally  high. To improve the usefulness of nations’ assessments of data confidence,  however, beginning with the 2004 submissions, developed nations must  quantify their confidence assessments.
subsections: section_title: The Four Developed Nations Rated Their Confidence in Their Most Recent Emissions Data as Generally High
paragraphs: As previously explained, the parties to the Framework Convention have  constructed an extensive system of estimating and reporting requirements,  buttressed by periodic reviews, to help nations produce inventory data that  are of high quality. The parties do not attempt, on the basis of the reviews  or any other means, to assign a grade or otherwise rate any nation’s success  in producing high-quality data. However, as one means of helping  developed nations identify areas where their data can be strengthened, the  parties require each nation to assess its confidence in the accuracy of its  own data. Specifically, the nations are required annually to analyze the  quality of the data they report (called an uncertainty analysis) for each gas  and for each major source of emissions and removals in each of the six  sectors. To do this, the nations have been encouraged, but not required, to  use the quantitative methods of uncertainty analysis included in the IPCC  good practice guidance. Alternatively, they could rely on qualitative means  to determine their confidence in these data. In either case, they have been  required to report whether they had high, medium, or low confidence in  each estimate of emissions of each of the six gases by each major source of  those emissions. The nations have not been required to report on their  confidence in the accuracy of the inventory data as a whole. The parties did  not provide further criteria for nations to use when determining which of  the three categories was most appropriate.
As required, all four developed nations reported high, medium, or low  ratings of confidence in their estimates for their 2001 emissions by source.   To determine the confidence each nation had in its inventory data as a  whole, we calculated the proportion of each nation’s data that  corresponded to each of the three rating categories. According to our  calculations, all four nations rated their confidence in their inventory data  as a whole as generally high, with the high-confidence ratings ranging from  about 75 percent for the United States to about 96 percent for Japan. The  high-confidence ratings occurred largely because the lion’s share of each  nation’s total emissions is carbon dioxide from fuel combustion, which can  be estimated with a relatively high level of confidence. Table 2 shows each  nation’s ratings for total emissions by gigagrams of carbon dioxide  equivalent, which is the unit of measurement used by the parties to the  Framework Convention to allow comparisons among greenhouse gases,  which differ in their effects on the atmosphere and expected lifetimes.
Although the national inventory reports contained some information about  the nations’ confidence in their data, none of the nations explained the  criteria they used to determine the high-, medium-, and low-confidence  ratings they reported.
section_title: Developed Nations Must Use Quantitative Methods to Assess Their Confidence in Their Data in 2004
paragraphs: In November 2002, the parties decided to require developed nations to use  the quantitative methods in the IPCC good practice guidance to develop  estimates of data uncertainty beginning with the 2004 submissions. Instead  of designating high, medium, or low ratings of confidence, under the new  requirements, developed nations must quantify their uncertainty in their  emissions estimates for each gas by each major source using 95 percent  confidence levels. In addition, they must combine the source uncertainty  estimates into a quantified uncertainty estimate for the inventory as a  whole and estimate the uncertainty in the trend between the base year and  the most recent year.
The IPCC good practice guidance provides detailed instructions for nations  to follow to produce the quantitative estimates of data uncertainty. The  guidance also describes two methods for combining quantitative  uncertainty estimates—one consisting of relatively simple statistical  calculations that result in a numerical uncertainty estimate, and the other  using computer simulation to calculate the estimates. The computer  simulation is a more sophisticated method and should result in more  accurate estimates; however, according to the EPA official responsible for  compiling the U.S. inventory, the computer simulation also is more costly  than the simpler method. Because of this, the good practice guidance states  that the nations must use the simpler of the two methods to produce their  combined uncertainty estimates; in addition, they are encouraged to use  the more sophisticated method when sufficient resources and expertise are  available.
For example, in its 2003 inventory submission, the United Kingdom used  both methods from the good practice guidance to quantitatively estimate  its confidence in its 2001 emissions data as a whole. Using the simpler  method, the United Kingdom reported an uncertainty value of 17 percent  for its inventory data as a whole; that is, the United Kingdom was 95  percent confident that total emissions were between 17 percent less and 17  percent more than the total of about 660,452 gigagrams of carbon dioxide  equivalent it estimated for the year. In contrast, using the more  sophisticated method, the United Kingdom reported an uncertainty value  of 13 percent, indicating it was 95 percent confident that total emissions  were between 13 percent less and 13 percent more than the year’s total  estimate.
According to the EPA official responsible for compiling the 2003 U.S.  inventory, the high, medium, and low categorizations reflect the early days  of developing inventories, before the IPCC had developed its good practice  guidance on quantitative methods. Prior to the guidance, the parties  recognized that nations would vary in their ability to perform quantitative  uncertainty analysis. The parties instituted the three-part categorization in  an effort to obtain information that was comparable across nations that  were using different methods for assessing data uncertainty. The parties  have moved to the quantitative methods because the three-part  categorization approach yielded limited information about data  uncertainty. For example, a nation could have uncertainty estimates of 35  percent and 60 percent but could have categorized both estimates as  medium. The quantitative estimates provide information about the  uncertainty of the various components of the inventory, thereby helping  nations identify areas in which improvements would have the greatest  effect on the accuracy of the inventory as a whole. In addition, the  quantified estimates make the uncertainty analyses more consistent and  understandable across nations. According to the Secretariat, the quantified  uncertainty analysis also better enables expert reviewers to determine if  nations are targeting their improvements in the appropriate areas.
section_title: The Parties Are Taking Steps to Improve the Quality of Emissions Data
paragraphs: To improve the quality of data on greenhouse gas emissions, the parties to  the Framework Convention are refining their requirements for both Annex  I and non-Annex I nations. In addition, they are bolstering the review  processes for Annex I nations. The changes are to begin to take effect over  the next few years. The parties currently have no plans to change the way  that non-Annex I nations’ inventories are assessed.
subsections: section_title: Changes in Requirements for Annex I and Non-Annex I Nations Take Effect over the Next Few Years
paragraphs: The parties have revised their requirements for both Annex I and non- Annex I nations, with the changes taking effect over the next few years.  The revisions fall mainly into two areas:  procedures for estimating  emissions and procedures for reporting those estimates.
The parties have revised both the estimating and reporting requirements  for Annex I nations. Regarding estimating, for example, beginning with the  2004 submissions, Annex I nations will be required to use both the 1996  IPCC estimating guidelines and the 2000 IPCC good practice guidance.  Previously, Annex I nations were required to use only the 1996 estimating  guidance and were encouraged, but not required, to use the good practice  guidance. Regarding reporting, the parties have specified in greater detail  than before the information that should be included in Annex I nations’  national inventory reports and in the data tables in the common reporting  format. For example, nations should include explanations of how they  recalculated their previous years’ data and, as previously discussed, the  methods they used to quantify their confidence in the data in their national  inventory reports. In their reports, nations should document that they  prepared their estimates in accordance with the IPCC good practice  guidance or explain why they did not; for example, an explanation is  required if they used a more sophisticated methodology than that specified  in the guidance. The nations should also cross-reference the information in  the national inventory report to explain the estimates reported in the data  tables. Furthermore, Annex I nations must submit their national inventory  reports following a specified format designed to facilitate review of the  inventories.
The parties also revised the reporting requirements for non-Annex I nations  that submit inventories in 2003 or later. Non-Annex I nations that had not  submitted an inventory prior to 2003 must include data in their initial  inventories for either 1990 or 1994 to establish an inventory baseline. Those  submitting their second inventories should provide data for 2000 as well.  This is in contrast to the requirement that Annex I nations submit data for  all years, from 1990 to the present. Similarly, the parties specified that non- Annex I nations should report data for carbon dioxide, methane, and  nitrous oxide and encouraged reporting of the other three gases— hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. In  contrast, Annex I nations are required to report data for all six gases.  According to the manager of the 2003 U.S. inventory, the estimating and  reporting requirements for non-Annex I nations are less demanding to  encourage those nations to report because those nations generally have  fewer resources available for reporting.
In addition, the parties have requested that the IPCC continue to improve  its guidance on estimating. Currently, the good practice guidance does not  address estimating emissions and removals for the land-use change and  forestry sector. According to the EPA official who managed the 2003 U.S.  inventory, the IPCC deferred guidance on estimating emissions and  removals because it was developing a special report on them, which was  subsequently published in 2000. On the basis of that report, the IPCC began  drafting new good practice guidance for estimating emissions and removals  for the land-use change and forestry sector, which is due to be completed in  late 2003. As part of this effort, the IPCC is also refining the data tables for  the land-use change and forestry sector. In addition, according to the same  EPA official, the IPCC is merging the 1996 guidelines with its good practice  guidance and expects to complete the effort by 2007.
section_title: The Parties Are Bolstering the Review Process for Annex I Nations, but Not for Other Nations
paragraphs: The parties are strengthening the expert review process for Annex I  nations’ submissions by conducting more reviews and standardizing the  review processes. Beginning with the 2003 submissions, each of the 39  Annex I nations will undergo one of the three types of expert reviews each  year:  an in-country review once every 5 years and either a desk review or a  centralized review in each of the intervening years. This requirement  contrasts with the practices of the past 3 years, when the experts  performed from 8 to 21 expert reviews in a year. Furthermore, to  standardize the reviews, the parties have spelled out, in greater detail than  before, the elements that are to be examined during reviews and have  developed a standardized format for reporting the results of the reviews. In  addition, according to EPA inventory managers, in another effort to make  the expert reviews more uniform, the Secretariat is developing a handbook  and a training program for the expert reviewers and has specified the  composition and responsibilities of the teams of expert reviewers.
According to the Secretariat, the parties have no plans to change the  assessment process for non-Annex I nations’ inventories, but the new  reporting guidance for non-Annex I nations would facilitate changes to the  assessment process, should the parties decide to institute them.
section_title: Scope and Methodology
paragraphs: To examine the results of the most recent expert reviews of the greenhouse  gas inventories submitted by the four economically developed nations  included in our study—Germany, Japan, the United Kingdom, and the  United States—we reviewed and analyzed the Secretariat’s status reports  showing the results of its initial reviews (called stage 1 reviews by the  Secretariat) of the most recently submitted inventories (2003). We also  reviewed the reports on the parties’ most recent expert reviews (called in- depth reviews by the Secretariat) of the four nations’ inventories (2000 for  Japan, 2000 and 2002 for the United Kingdom, 2000 for the United States,  and 2001 for Germany) and related documentation on reporting  requirements and review processes issued by the Secretariat. We  interviewed officials at EPA who manage the U.S. greenhouse gas inventory  and serve as inventory experts for the parties, as well as officials from the  State Department’s Bureau of Oceans and International Environmental and  Scientific Affairs who are responsible for policy issues related to the  Framework Convention. In addition, we reviewed and analyzed the limited  information provided to us by the Secretariat in response to questions we  posed.
To describe the results of any assessments of inventories of the three  developing nations included in our study—China, India, and Mexico—we  reviewed and analyzed the Secretariat’s reports on its assessments of  inventories submitted by non-Annex I nations, including the latest  inventory submitted by Mexico (2001); related documentation on non- Annex I nation reporting requirements and assessment processes; and  other Secretariat information documenting which non-Annex I nations  have submitted inventories. We also interviewed the officials at EPA and  the Department of Energy who are most familiar with the three nations’  efforts to compile and report their inventories, as well as the cognizant  officials from the State Department.
To determine the extent to which the developed nations have confidence in  their data, we analyzed the confidence information each nation provided in  its 2003 submission. To describe any changes in assessing confidence in the  data that are to take effect in the future, we examined documentation from  the Secretariat and the relevant sections of the four developed nations’  2003 submissions.
To describe the steps the parties are taking to improve the quality of future  inventory data and determine when those improvements might be in place,  we reviewed and analyzed documentation of the parties’ new estimating,  reporting, and review requirements; interviewed cognizant EPA officials;  and reviewed and analyzed the limited information on this issue submitted  to us by the Secretariat in response to questions we posed.
We performed our work between November 2002 and November 2003 in  accordance with generally accepted government auditing standards.
section_title: Agency Comments
paragraphs: We provided a draft of this report to the Secretary of State, the  Administrator of EPA, and the Framework Convention Secretariat for  review and comment. EPA provided clarifying comments, which we  incorporated where appropriate. We did not receive comments from the  State Department or the Framework Convention Secretariat.
As arranged with your offices, we plan no further distribution of this report  until 30 days after the date of this letter, unless you publicly announce its  contents earlier. At that time, we will send copies of this report to  interested congressional committees; the Chairmen and Ranking Minority  Members, Senate Committee on Appropriations, House Committee on  Appropriations, Senate Committee on Governmental Affairs, and House  Committee on Government Reform; the EPA Administrator; and the  Secretary of State. We will make copies available upon request to other  interested parties. This report will also be available at no cost on GAO’s  Web site at http://www.gao.gov.
If you or your staffs have any questions about this report, please call me at  (202) 512-3841. I can also be reached at stephensonj@gao.gov. Key  contributors to this report are listed in appendix II.
section_title: Results of Expert Reviews of the Four Developed Nations’ Inventories
paragraphs: The six expert review reports we examined did not follow identical  formats; however, they generally highlighted the experts’ findings and  suggestions for improvement in a summary section at the beginning of each  report.  The experts noted instances of noncompliance with the reporting  requirements.  In addition, the experts noted some instances in which the  nations did not comply with the Good Practice Guidance and Uncertainty  Management in National Greenhouse Gas Inventories, even though  following the good practice guidance was not a requirement at the time that  the inventories were submitted.  The summary-level findings and  suggestions for each of the six expert reviews we examined are listed in  table 3.
section_title: GAO Contacts and Staff Acknowledgments
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section_title: Staff Acknowledgments
paragraphs: In addition to the individuals named above, Simin Ho and Karla Springer  made key contributions to this report.  Nancy Crothers, Sandra Edwards,  Barbara Johnson, Karen Keegan, Andria Key, Charlotte Moore, Chris  Moriarity, Katherine Raheb, and Anne Rhodes-Kline also made important  contributions.
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