Action - Commit to conducting an emissions inventory
The Mayors Climate Protection Agreement suggests that you “inventory global warming emissions in City operations and in the community, set reduction targets and create an action plan.”

We think this is a critical first step to effectively reducing them. If you don't know where you started, how will you know if you're making progress? And having a clear understanding of where most of your emissions are generated is very helpful when you're developing your climate action strategy.

Action – Determine the scope of your inventory
Before you begin collecting data for your emissions inventory, you need to identify the sources of your emissions and then decide which ones you're going to include in your inventory. In a nutshell, the where and that what of your inventory.

Your organizational boundary is the where. For your community the most straightforward definition of this boundary is the community’s geographical limits. For your city operations this boundary isn’t necessarily so straightforward since there are numerous buildings, departments, fleets etc. Will you include them all? Or will you include only some of them? If so, which ones? We encourage you to be as inclusive as possible, but either way, it is important that you clearly define this boundary. 

Your operational boundary is the what. What emission sources within your organizational boundary should you/will you include? The GHG Protocol, the accounting framework for nearly every GHG standard and program in the world, stipulates that you include all emissions generated from directly burning a fuel (e.g. natural gas in your furnace or gas in your car) and those created in the generation of any purchased energy such as electricity, steam or chilled water. These emissions absolutely should be included.

Your city and community be indirectly responsible for the creation of other emissions. These are the ones that are considered optional to include in your inventory. For example, most cities don't include the emissions created from aircraft that utilize their municipal airport since there is little the city can do to reduce them. The emissions generated by operating the airport should be included, but not necessarily those generated by aircraft.

Be sure to be transparent about what all is included and excluded. Carefully documenting the scope of your inventory will allow for meaningful comparisons with future inventories.

Action – Select a base year
After defining the scope of your inventory, you need to figure out which year is going to be your base year -the same year for which you will conduct your first emissions inventory. When choosing a base year keep in mind that you will need energy usage and other data from that year.

The Kyoto Protocol suggests a base year of 1990, long before computers and electronic record keeping were commonplace. As a result data collection may require digging through old boxes and archives, and in some cases you may not be able to find all of the data necessary for a comprehensive and complete 1990 inventory. In cases such as this, selecting a more recent year is advised.

GCBL selected 2005 as a base year for the Northeast Ohio inventory we conducted in 2007.  Three Northeast Ohio cities, Cleveland, Akron and Oberlin, also used 2005 as a base year for their inventories. 

Action – Set emissions reduction goals
Now that you’ve selected your base year you can begin to think about your emission reduction goals. In signing the U.S. Mayors Climate Protection Agreement you're committing to meeting or exceeding the reduction target set in the Kyoto Protocol, which for the U.S. is 7% below 1990 levels by 2012.

The IPCC recommends much deeper emissions reductions of 25 to 40% below 1990 levels by 2020 and 80 to 90% by 2050. We recommend that you consider targets more in line with these. While these targets may seem more extreme and harder to achieve, they’re scientifically based and have established to avoid warming exceeding two degrees Celsius - the threshold at which the vast majority of today’s climate scientists believe dangerous, irreversible changes in the climate system will occur.

GCBL's emissions reduction plan was developed around the goals of 50% below the 2005 by 2030 and 90% by 2050.

London has set a target of reducing emissions 60% below 1990 levels by 2025!

Action – Perform an emissions inventory for both city operations and the community
The most difficult part of this process is collecting the data. Actually calculating the carbon footprints is relatively easy, thanks to a number of user friendly tools designed to do just that. 

The GreenCityBlueLake Institute recommends that your community consider joining the international non-profit group ICLEI - Local Governments for Sustainability, a membership association for local governments committed to climate protection and sustainability. There is an annual membership fee, but the benefits of membership are numerous and invaluable. Among the benefits of membership is access to their Clean Air Climate Protection (CACP) software, a very user friendly inventory, forecasting, and climate action planning tool.

Another membership based option would be to join The Climate Registry. "The Climate Registry establishes consistent, transparent standards throughout North America for businesses and governments to calculate, verify and publicly report their carbon footprints in a single, unified registry." Their greenhouse calculation tool, the Climate Registry Information System (CRIS), is available online. One of the primary differences between this path and others is that members are required to verify their emissions and publicly report them.

While we recommend that your city consider joining ICLEI, there are several free inventory tools available to you as well.

• The Greenhouse Gas Protocol Cross Sector Tools 
  • These are downloadable Macro enabled Excel spreadsheet based calculators
  • The Greenhouse Gas Protocol Public Sector Standard (coming soon) will be a good guidance document to use with these tools