Colorado Greenhouse Gas Inventory

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Greenhouse Gas Inventory


The purpose of Colorado’s Greenhouse Gas Inventory Report is to provide the most complete, accurate, precise, consistent, and comparable picture of emissions. The report covers emissions activities within the state and spans all the years of concern. 

The science of climate change is rich in scope and complexity — and continues improving. Colorado uses the best available data and evaluation methods each time updates the Greenhouse Gas Inventory Report. Numbers and trends may change from one inventory report to the next. This is a normal part of how science works and helps ensure information is becoming more accurate over time.

In 2019, Colorado adopted Senate Bill 19-096 (SB 19-096). This law requires the Air Pollution Control Division to publish an updated statewide greenhouse gas inventory at least every two years. Colorado also adopted  House Bill 19-1261 (HB19-1261) in 20129. This law established the first statewide greenhouse gas reduction goals. It also requires progress reports to the legislature every odd-numbered year. 

Each updated Greenhouse Gas Inventory Report includes past, recent, and projected  emissions for the following sectors: 

  • Agriculture.
  • Coal Mining.
  • Electric Power.
  • Industrial Processes and Product Use.
  • Land Use, Land Use Change, and Forestry.
  • Natural Gas and Oil Systems.
  • Residential, Commercial, and Industrial (RCI) Fuel Use.
  • Transportation.
  • Waste Management.


Each updated Greenhouse Gas Inventory Report uses reported data from air pollution sources and other data, such as the U.S. Environmental Protection Agency’s State Greenhouse Gas Emissions and Removals dataset or the State Inventory Tool.

The Greenhouse Gas Inventory is published every two years. The next inventory will be released in 2023. Major changes anticipated in the 2023 inventory include:

  • Updated data sources and methods. 
  • A change in global warming potentials used. The new inventory will use going from the United Nations Intergovernmental Panel on Climate Change 5th Assessment Report (AR5).
  • Changes in total emissions, the baseline, and sector-wide emissions.
  • The report will be more detailed than previous reports and better align with the national inventory.
  • Improved transparency. All supporting data will be publicly available.


Past Greenhouse Gas Inventory Publications:


Current information on critical metrics that impact greenhouse gas emissions between inventories is available in the Greenhouse Gas Metrics dashboard. This information is available in English and Spanish.

For information related to public meetings and other stakeholder engagement opportunities, explore the Stakeholder Opportunities and Involvement section below.

For greenhouse gas inventories published in 2023 and beyond, the emissions data will represent a combination of reported and modeled data.

The 2014, 2019, and 2021 greenhouse gas inventories primarily relied on EPA’s State Inventory Tool to generate emissions data . Beginning with the 2023 inventory, Colorado will rely on that EPA tool only for estimating emissions associated fossil fuel burning. Other sectors, like land use and waste, will rely on the EPA’s Inventory of U.S. Greenhouse Gas Emissions and Sinks by State dataset. 

Additionally, emissions reported to the EPA per their Greenhouse gas Reporting Program — as well as those reported to the State of Colorado per the requirements of Colorado Air Quality Regulation 22, Part A, and Colorado Air Quality Regulation 7, Part D., Sections IV. & V. — will be used as much as possible in the industrial sector, as directed under state law. 

Finally, estimates for the oil and gas sector in the 2023 inventory will continue to rely mostly on a model developed by the Air Pollution Control Division. This model was used in the 2021 inventory. 

The historical data presented in inventories published before 2023 are based on various modules in the EPA’s State Inventory Tool. The modules are updated regularly by EPA with current activity data. The modules are published with those updates annually to reflect real-world data as it becomes available. 

The 2023 greenhouse gas inventory update and publication process presents a lag in the availability of historical data the EPA’s State Inventory Tool can generate. For instance, the EPA’s State Inventory Tool data used in the 2021 inventory only includes historical emissions from the EPA’s State Inventory Tool through 2018. Because future inventories will continue to rely on EPA data released through a similar process, those inventories will continue to publish historical emissions results with a similar lag from the date of publication. The division continually seeks ways to reduce this lag so reports are as relevant as possible.

It is important to note that development of the Colorado statewide Greenhouse gas Inventory is a process of continual improvement. Future reports will continue to expand the quantity and quality of data sources and methods. Each refinement comes with possible revisions to historical estimates, including updates to baseline and target years. This is a mandatory part of the process to ensure that all years are comparable in any given snapshot. 

Similarly, future projections are continually revisited to remain in sync with the latest historical estimates and to incorporate new policy measures.

EPA State Inventory Tool modules used for the 2014 inventory report.

The Air Pollution Control Division published a report to meet requirements in the “Resolution to Ensure Greenhouse Gas Reduction Goals Are Met” adopted by the Colorado Air Quality Control Commission on October 23, 2020. The division conducted its evaluation for the report in August 2022 as required by the resolution. The division submitted the report to the commission.

Air Quality Control Commission GHG Reduction Goals Progress Report

To meet the requirements from House Bill 19-1261, the Air Pollution Control Division must:

  • Track progress toward state greenhouse gas reduction goals.
  • Provide any updated cost-benefit analysis developed for rules adopted to attain the goals.
  • Make recommendations on future legislative action to address climate change. 

The division submitted its first report to the Colorado General Assembly in December 2021.

2021 Greenhouse Gas Emissions Reduction Progress Report to Colorado Legislature

2023 Greenhouse Gas Inventory Fact Sheet in English and Español

Materials for Public Comment (due December 17, 2023)

Please provide written comments using this form by December 17, 2023. Attachments can be emailed to climatechange@state.co.us. (Note all comments are publicly available but your contact information will not be posted.)

  • Updated Draft: 2023 Statewide Greenhouse Gas Inventory (v2)
    • This updated draft includes new content and edits to the previously release Draft (v1).
    • Some sections have seen the addition of, removal of, or edits to individual words or as much as entire paragraphs. 
    • New sections include:
      • Section The Science of Global Warming and Climate Change
      • Section Regional and State Effects of Climate Change 
      • Section Historical Emissions - IPCC
      • Section Emission Projections
      • Section Energy Policy Simulator via RMI and Roadmap 2.0 Development
      • Section 2.8 Projections and Progress Towards Statutory Targets 
      • Almost all text in Chapter 8 Global Warming Potential Comparisons
      • Chapter 9 References and Resources
      • Appendices A, B, and C
  • Markup Version of the Draft 2023 Statewide Greenhouse Gas Inventory
    • This file identifies the changes made between the first (v1) and updated (v2) draft reports. Please note that this markup file focuses on highlighting substantive changes, so not every detail is provided and the page numbers may not be in alignment due to the modified structure. New content is highlighted green and deleted or replaced content has been struck through. Comparison is not offered for the Table of Contents, List of Tables, List of Figures, Acronyms & Abbreviations, Units, or Definitions sections.
  • First Draft: 2023 Statewide Greenhouse Gas Inventory (v1)
  • Draft 2023 report to the legislature: Progress Toward Reduction of Statewide Greenhouse Gas Pollution (expected to be available by December 31, 2023).


Upon request, the Air Pollution Control Division can provide a meeting with staff to share the general content of these documents. Language interpretation is also available upon request. Please email climatechange@state.co.us to make a request. The final inventory will be published by the end of 2023. 

The division will publish a plain-language executive summary of the Greenhouse Gas Inventory on this website for public review in early 2024. The executive summary will be available in English and Spanish.

Previous stakeholder engagement opportunities:

Contact Us


If you have questions or comments about Colorado's greenhouse gas inventory, email climatechange@state.co.us. Please include "GHG Inventory" in the subject line. You can also sign up for email updates on the Colorado Department of Public Health and Environment's ongoing work to address climate change and protect clean air.

Stay up-to-date on the Colorado Department of Public Health and Environment's efforts to reduce GHGs, Climate Equity, and other air quality issues by signing up for e-mail updates.