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Colorado Greenhouse Gas Inventory

Help in your language: Free language assistance services are available to you. To request assistance in another language, email cdphe_apcd_outreach@state.co.us. Please include the topic and “language assistance” in the subject line. Please also link to the specific information you’d like to access, if possible, such as a web page or document.

Ayuda en el idioma de su preferencia: ofrecemos asistencia en el idioma de su preferencia, sin cargo alguno. Si desea solicitar asistencia en español o en otro idioma, envíe un correo electrónico a cdphe_apcd_outreach@state.co.us. Indique el tema y la frase “language assistance” (asistencia en otro idioma) como asunto de su mensaje. De ser posible, incluya un enlace a la información que desea consultar, como la página web o el documento.

Overview

In 2019, Colorado adopted Senate Bill 19-096. This law requires the CDPHE Air Pollution Control Division to publish an updated statewide Greenhouse Gas Inventory Report at least every two years.

Colorado also adopted House Bill 19-1261 in 2019. This law established the first statewide greenhouse gas reduction goals. To coordinate actions for meeting these goals across several state agencies, the Colorado Energy Office developed the state’s Greenhouse Gas Pollution Reduction Roadmap. This law also requires the CDPHE Air Pollution Control Division to share an update on the state’s progress towards the reduction goals with the legislature every odd-numbered year.

In 2023, Colorado adopted Senate Bill 23-016. This law enhanced Colorado’s greenhouse gas reduction goals. It established a net-zero target for 2050 and added interim targets every five years.

Greenhouse Gas Inventory Report

The purpose of the Greenhouse Gas Inventory Report is to provide the most complete, accurate, precise, consistent, and comparable picture of emissions. Each report covers emissions activities within the state back to 2005 as well as projected future emissions under different policy action scenarios.

The science of climate change is rich in scope and complexity and continues to improve. Colorado uses the best available data and evaluation methods each time it 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 becomes more accurate over time.

The CDPHE Air Pollution Control Division originally published the 2023 Greenhouse Gas Inventory Report in December 2023. The division also prepared a one-page overview and an executive summary of the report. In November 2024, the division published an updated version of the 2023 Greenhouse Gas Inventory Report and updated data.

Starting in 2023, each updated Greenhouse Gas Inventory Report includes past, recent, and projected emissions for the following sectors:

  • Energy.
  • Industrial Processes and Product Uses.
  • Agriculture.
  • Land Use, Land-Use Change, and Forestry.
  • Waste.

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 Greenhouse Gas Emissions and Removals and Sinks by State dataset or the State Inventory Tool.

Major changes in the updated 2023 Greenhouse Gas Inventory Report include:

  • Changes to historical Natural Gas and Oil Systems estimates.
  • Incorporation of the latest emissions projections, which are more current than those published in the 2024 Greenhouse Gas Pollution Reduction Roadmap 2.0.
  • Evaluation of progress toward electric utilities retail sales-based emission targets.

Major changes in the 2023 inventory compared to previous inventories include:

  • Updates to data sources and methods.
  • Addition of emissions from newly quantifiable sources.
  • Changes in global warming potentials from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) to the Fifth Assessment Report (AR5).
  • Changes in emissions for all years from 2005 to 2020. 
  • Greater depth in analyses.
  • Changes in organization to better align with the U.S. EPA National Inventory.
  • Improvements in transparency and data availability.

Detailed changes from the December 2023 version to the November 2024 version of the Colorado 2023 Statewide Greenhouse Gas Inventory Report are provided in the link below:

If you would like to access any previous inventories, draft releases of the 2023 Inventory, or have any questions, email climatechange@state.co.us.

Greenhouse gas data sources

It is important to note that the 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 policy measures.

Prior to the 2023 Greenhouse Gas Inventory, inventories primarily relied on the U.S. EPA’s State Inventory Tool. The modules used for the 2014, 2019, and 2021 inventories are available upon request.

Greenhouse Gas Inventory Explorer

The Greenhouse Gas Inventory Explorer complements the latest Colorado Greenhouse Gas Inventory Report, and empowers users to interact with the same data provided in the Inventory report in an intuitive and meaningful way, providing a dynamic and engaging experience. By offering an alternative visual representation of the Inventory’s data, the tool enables users to explore, analyze, and interpret the Inventory’s key findings with greater depth and clarity. This tool aims to enhance users' understanding of the complex information presented in the Inventory and will be updated in conjunction with each Inventory and/or more frequently with latest modeled projections.

Reports and updates to the Air Quality Control Commission

The 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.

Reports to the legislature

To meet the requirements from House Bill 19-1261 (§ 25-7-105(1)(e)(VII), C.R.S.), every odd-numbered year, the division must:

  • Track progress toward state and sector-specific greenhouse gas reduction goals.
  • Provide any updated cost-benefit or regulatory analyses developed for rules adopted to attain the goals.
  • Make recommendations on future commission rules or policies sufficient to achieve the goals.
  • Make recommendations on future legislative action to address climate change. 

2023 Greenhouse Gas Emissions Reduction Progress Report to Colorado Legislature

2021 Greenhouse Gas Emissions Reduction Progress Report to Colorado Legislature

Stakeholder opportunities and engagement

Upon request, the division can provide a meeting with staff to share the general content of these documents. Language interpretation is also available upon request. Email climatechange@state.co.us to make a request. 

Documents from previous stakeholder engagement opportunities are available upon request, including presentation slides and meeting recordings. To request them, please email cdphe_climatechange@state.co.us, putting the topic or document type in the subject line.

Contact us

If you have questions or comments about Colorado's greenhouse gas inventory, email climatechange@state.co.us with the subject line "Greenhouse Gas Inventory.” 

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