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Measuring For Climate Change Policymaking

Addressing global climate change means reducing GHG emissions from fossil fuel combustion and, where possible, converting emission sources into emission sinks. Knowing the total quantity of GHG emissions generated and sequestered in-state, is critical to effective state-level policymaking. All states that currently have or are drafting climate legislation include statewide inventories of GHG emissions sources and sinks by fuel and by sector in their policies. In addition, a number of states not currently involved with state-level climate change policymaking are creating inventories for informational purposes. Having an inventory of emissions over time allows states to set overarching statewide emission reduction targets and to prioritize sector and emission source-based standard setting and incentive structures.

The old adage, “what is measured is managed,” rings true in the GHG emissions arena. Taking an inventory of emissions gives policymakers a better understanding of the activities that generate emissions in-state, such as electricity generation, transportation, agriculture, and residential heating. This, in turn, drives policymaking. For example, a state in which 15 percent of total GHG emissions are from electric power production and 40 percent are from automobiles may want to focus resources on transportation planning and public transportation. A state with relatively low emissions in the transportation sector but significant emissions in the electric power generation, residential and commercial energy use sectors may want to focus initial efforts on promoting renewable power generation and energy efficiency improvements in the built environment. States should also identify the potential to turn landbased emission sources into sinks, particularly in the agricultural sector and with regards to forestry and additional natural resource management. The potential to enhance “carbon sinks” on state-owned and private lands may be significant in some areas.

A state can produce an inventory internally, or with the assistance of experienced consulting organizations. The not-for-profit Center for Climate Strategies has helped a number of states prepare inventories and use them to guide policymaking. In addition to quantifying GHG emissions across sectors and activities, a few states are beginning to engage third-party auditors to verify inventory calculations and establish protocols for verification of emission reports from soon-to-be regulated firms.

Comparing Emission Sources and Sinks Across States


The figure above illustrates potential variation in GHG emission sources and sinks across states as percentages of total state GHG emissions. Connecticut has a relatively small quantity of emissions generated in the electricity sector compared to the other three states, but a significantly greater proportion of total emissions from residential, commercial, and industrial direct fossil fuel use compared with North Carolina, Minnesota, and particularly New Mexico. Connecticut also has a greater share of emissions from transportation than the other states. Connecticut, North Carolina and New Mexico have all identified forestry and land use practices as net carbon sinks, while Minnesota has identified land use practices as a net GHG emission source.