A mandatory greenhouse gas (GHG) reporting and disclosure program is an essential first step in any effort to reduce U.S. GHG emissions. The program should be comprehensive, but should be implemented in phases to allow for the development of widely accepted and sound reporting protocols. Ultimately, the program should:
Human activities are increasing atmospheric greenhouse gas (GHG) concentrations. Evidence is growing that rising global temperatures, higher sea levels, changing precipitation patterns, and other adverse impacts will result. Since the United States is the world’s largest GHG emitter, no strategy to address global climate change can succeed without substantial and permanent reductions in U.S. emissions. Efforts to date have failed to curb the overall growth in U.S. emissions, which have increased by 14.1 percent since 1990.1 
A number of policy options aimed at securing emissions reductions are discussed in another policy brief published by the Pew Center on Global Climate Change, entitled The U.S. Domestic Response to Climate Change: Key Elements of a Prospective Program . That policy brief outlines elements of a domestic climate change program that would: (1) improve the tracking and reporting of GHG emissions, (2) promote new technologies and practices, and (3) secure long-term emissions reductions through a flexible mandatory program, such as a mandated cap on GHG emissions with market-based trading of emissions credits.
This brief provides additional guidance regarding the first step in any domestic program: a reliable and credible system for tracking and reporting GHG emissions. Similar to the federal Toxics Release Inventory (TRI) program, a mandatory GHG reporting program would apply to all major sources of GHG emissions and require disclosure of their reports in a publicly accessible Internet-based database. Such a reporting program would: (1) provide a solid foundation for a U.S. program to reduce GHG emissions, (2) provide the basis for government assurances that companies would not be penalized for their early reductions under a future climate policy, and (3) potentially create a powerful incentive for voluntary reductions.
To achieve these objectives, a sound GHG reporting program must strike a balance between comprehensive tracking of the various greenhouse gases emitted by major sources and minimization of program costs borne by both reporting entities and the administering federal agencies. While the ultimate program should include major direct GHG sources, as well as significant indirect sources,2  such as imports of electricity and product use emissions, a phased approach is likely to be most feasible. This brief describes a program that would ultimately include at least 75 percent of human-induced GHG emissions in the United States.
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