California's Global Warming Solution Act of 2006 mandates that facilities emitting more than 25,000 metric tons of carbon dioxide equivalents annually from stationary combustion must report emissions starting this year. This could affect public agencies that have diesel generators, landfill gas flares, wastewater digester gas combustion, water pump engines, and/or green waste grinders. It's also likely that the rule will be extended in the future to cover more specific sources — such as landfills.

In June, California's Air Resources Board (CARB) released the details on how to determine and calculate how much greenhouse gas an agency or company produces. They have two choices: management control and equity share.

Management control is simpler, but forces a public agency to take credit for all emissions if it controls more than 50% of an operation. Equity share more accurately reflects distribution among a public agency and a for-profit entity, but detailed financial and management stake analyses are required to divvy up responsibility by percentage.

Mandatory reporting under California's Global Warming Solutions Act of 2006 focuses on specific emissions sources. But voluntary reporting programs enable cities and counties to determine a more true carbon footprint of operations by allowing coverage of a much wider range of sources. Whether or not they are subject to mandatory reporting, public agencies can report emissions through the California Climate Action Registry (CCAR) or The Climate Registry (TCR), which serves multiple U.S. states, some Canadian provinces, and a few Mexican states. Eventually, most cities and counties in California will be subject to mandatory reporting requirements, at which time they will be forced to report emissions to CARB; however, they can always voluntarily provide additional data to CCAR or TCR.

Formed in 2001, CCAR may give up its voluntary registry program for annual emission inventories next year to become the registry for reduction credits as part of a regional voluntary carbon market and California's cap-and-trade program. If that happens, TCR will be the primary and perhaps only voluntary registry for emissions in North America.

The registries share a Los Angeles office, have similar protocols, and accept reports that include emissions of six Kyoto-established pollutants: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). Limited reporting options are available under both registries during the initial years of membership, such as CCAR's allowance for participants to “opt to limit their reports only to carbon dioxide emissions during the first three years of participation.” Ultimately, though, reporting requirements will apply to all six Kyoto pollutants.

Both registries require reporting on direct emissions “from sources owned or controlled by the reporting entity,” and only “encourage” reporting indirect emissions like employee commuting and business travel or product disposal and transport of purchased raw materials.

Reporting under CCAR is done through CARROT, the registry's online calculation tool. TCR has a similar online tool called CRIS. Learning how to use these tools is another basic step that public agencies are taking toward completing their inventories.

California generates 6.2% of the nation's, and 1.4% of the world's, greenhouse gases. In 1990, the state emitted 427 million metric tons carbon dioxide equivalent; 2020 levels are projected at 600 million. The goal of the state's Global Warming Solutions Act is to bring the 2020 projection down to the 1990 level. Source: California Air Resources Board

California's pending emissions cap-and-trade program is the cap and trade program the cornerstone of the cornerstone of the state's Global Warming Solutions Act. At this time, , it is unknown what sources or entities will be subject to the cap; however, it would be prudent for any agency to assume it will have to reduce emissions to achieve its 1990 baseline.