Greenhouse Gas Inventory
The City tracks the amount of greenhouse gases (GHGs) being emitted in Encinitas because it indicates how much our community is contributing to climate change. A GHG inventory is a monitoring tool used to report on the implementation of the City’s Climate Action Plan (CAP). It helps to understand the source and amount of GHG emissions being generated, as well as track the progress towards CAP emission reduction targets.
The following section demonstrates the City’s efforts in lowering local GHG emissions.
The primary greenhouse gases (GHGs) emitted in the City of Encinitas include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulfur hexafluoride (SF6), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs). Each GHG has varying levels of potency in the atmosphere, therefore, to simplify the discussion and comparison of emissions, the Climate Action Plan (CAP) uses a measurement referred to as carbon dioxide equivalent (CO2e), which is measured in metric tons (MT).
Last updated May 10, 2023
GHG Emissions Inventory
Completing GHG inventories is essential to achieving the main objective of the City’s CAP, which is to meet targeted reductions in emissions by 2020 and 2030. GHG inventories are conducted periodically to provide a snapshot of emissions each year and help develop emissions trends over time. The City’s baseline inventory completed for the 2018 CAP estimated GHG emissions from sources in Encinitas to be 459,000 metric tons of carbon dioxide equivalent (MTCO2e) in 2012.
The most recent GHG emissions inventory was completed in 2023, by San Diego Association of Governments (SANDAG) as part of their Regional Climate Action Planning Framework & Monitoring Program. This most recent inventory reflects GHG emissions from the year 2020.
Using the best and most currently available data and modeling methods, citywide GHG emissions in the City of Encinitas were determined to be 391,800 MTCO2e in 2020. Since transportation emissions data was not included in SANDAG’s 2020 GHG Inventory due to unreliable vehicle miles traveled (VMT) modeling for that year, the City used 2018 transportation emission data as a proxy for 2020. Annual VMT data generated by SANDAG are forecasted estimates from their regional activity-based model (ABM). The most recent activity-based model, ABM2+, was last calibrated with observed data from 2016. Any forecasted VMT data for 2020 would not take into account the impacts of the Covid-19 pandemic and therefore would not be an accurate estimate for that year. Historically, on-road transportation makes up the largest share of the City’s GHG emissions.
Note: The 2020 GHG inventory is based on best available emissions data. All listed sectors include data for 2020 except transportation, which includes data from 2018, as explained above.
Last updated May 10, 2023
GHG Emissions Calculations and Trends
GHG emissions are calculated by multiplying activity data (e.g., kilowatt-hours of electricity, tons of solid waste) by an emission factor (e.g., pounds of CO2 per unit of electricity). Running these calculations involves, among other things, a sophisticated regional transportation model using citywide and regional data. Measuring emissions from transportation is one of the most challenging sectors to evaluate.
As climate science continues to advance and evolve, emissions calculation methodologies will vary from year to year, making direct comparisons difficult. Annual GHG inventories are best compared by evaluating the general trends in data over time.
The City’s CAP set a GHG emissions reduction target of 13% below 2012 levels by 2020. In 2020, emissions went down by 14.6% from the 2012 baseline level. While some sectors showed greater emissions reductions than others, overall, this demonstrates that the City achieved its 2020 target, exceeding it by 1.6%! It is also important to note that the 2020 inventory does not include reductions realized from actions the City has taken within the last two years. Most notably, with the formation of San Diego Community Power, the City began serving Encinitas residents and businesses with 100% renewable electricity in 2021, vastly reducing GHG emissions from this sector. Electricity emissions are expected to decrease to nearly zero in future GHG inventories.
Note: The 2020 GHG inventory is based on best available emissions data, which includes 2020 data for all sectors except transportation, which relies on data from 2018.
Last updated May 5, 2023