Greenhouse Gas Emissions in Boulder County, CO

Boulder County residents are already experiencing the impacts of the climate crisis in the form of high heat days, extreme weather, drought, poor air quality, unpredictable precipitation, and catastrophic wildfires. As temperatures rise, the number of extreme weather events and wildfires will continue to increase. Climate-related disasters are personally affecting residents of Boulder County while also becoming more pervasive regionally. Climate change disproportionately impacts communities of color and low-income communities. Climate change impacts also carry an enormous price tag for local governments.

Boulder County has been in a continuous state of disaster recovery since the 2010 Fourmile Canyon Fire, which signaled the beginning of increased wildfire activity across the county.  Damages from the catastrophic 2021 Marshall Fire totaled more than $2 billion, becoming one of the most expensive wildfires in national history.

To align with science-based targets and the IPCC’s call for limiting global average warming to 1.5°C, Boulder County has updated our emissions reduction goal: Boulder County is now committed to reducing countywide emissions 80% from 2021 levels by 2030 and achieving carbon neutrality by 2035.

In the last five years, since 2016, we’ve reduced emissions 16%. To meet our 2030 goal, we need to more than triple the rate of emissions reduction in the next 8 years (2022 to 2030), and drastically decrease from 12 mt CO ₂ e per person to 2 mt CO ₂ e per person.

A greenhouse gas (GHG) inventory is a helpful tool that quantifies our emissions resulting from human activities and helps us track progress towards emissions reductions goals. Boulder County completes GHG emissions inventories roughly every five years, using the Global Protocol for Community-scale GHG Emissions Inventories (GPC). The GPC is a globally-recognized process and standard designed for cities and counties to account for and report GHG emissions. These inventories quantify the emissions countywide, as well as broken down by sector and community. With this information, we can understand the largest sources of carbon emissions and take focused action to drastically reduce our emissions.

In 2021, Boulder County produced 4.1 million mt CO ₂ e: or an average of 12 mt CO ₂ e per person annually. The 2021 emissions are shown by sector in the graph above. Boulder County categorizes its GHG data into seven commonly-used sectors, shown in the graph.

• Building energy use (i.e. primarily due to electricity and natural gas use) was the greatest emitting sector, comprising 64% of total countywide emissions (with 40% of total emissions coming from commercial buildings and 24% from residential buildings).
• Transportation was the second-greatest emitting sector, making up 26% of total countywide emissions. Gasoline and aviation fuel were the greatest transportation-related emissions sources.

Boulder County recorded a 16% overall reduction of GHG emissions from 2016 to 2021 despite a 5% population increase in the same time period. The municipalities in Boulder County had reductions in GHG emissions ranging from 7% to 25%.

• Since 2016, electricity emissions countywide have decreased 20%, largely due to the growing proportion of electricity that is sourced from clean and renewable energy sources.
• Since 2016, natural gas use emissions increased 11%, which can be attributed to the increase in the county’s population, a colder winter, and the 6% increase in the global warming potential of methane.
• Since 2016, transportation sector emissions countywide have decreased 31%. This is due, in part, to travel restrictions and an increase in the population working from home with the COVID-19 pandemic.

Based on these results, programs and policies aimed at reducing emissions related to building energy use and transportation activities have the greatest potential to reduce emissions.

A traditional greenhouse gas inventory accounts for all emissions within the geographic area. It does not account for emissions associated with what residents consume from outside our boundaries, such as food or goods and services. That is why, for the first time ever, Boulder County also completed a Consumption-Based Emissions Inventory (CBEI). The CBEI will enable the county to understand the emissions that may occur anywhere in the world—directly or indirectly—as a result of the activities of Boulder County residents.

Boulder County’s 2021 CBEI shows that we produced a total of 6.0 million mt CO ₂ e. Housing, transportation, and services account for over 69% of total emissions. In Boulder County, the typical household emitted roughly 43 mt CO ₂ e, or about 19 mt CO ₂ e per person—that needs to come down to 2 mt CO ₂ e per person by 2030 if we are to meet our updated goal.

The CBEI inventory provides Boulder County and the community the opportunity to better understand how our choices and the following activities impact our GHG emissions: our consumption of goods and services; the importance of dense, affordable, and transit-oriented housing; and whether we source renewable energy or fossil fuels to power our homes, businesses, and transportation.

You can find out more about the CBEI by clicking  here .

Based on the results of the inventory, programs and policies aimed at reducing emissions related to building energy use and transportation activities have the greatest potential to reduce countywide emissions. There are significant opportunities to reduce energy-related GHG emissions through widespread electrification (i.e. building and transportation decarbonization) and more aggressive renewable energy and efficiency policies. It’s essential that communities vulnerable to climate risk have access to support and resources to adapt to and recover from climate impacts and disasters. For more information, see the strategies in the climate action website (coming soon) and in the Boulder County 2023 Sustainability Plan available  here .

 Colorado House Bill 19-1261 , requires all electric utilities statewide to reduce their GHG emissions by 80% from 2005 levels by 2030. Xcel Energy, which provides 73% of the total electricity consumed in the County, has internal goals that surpass the 80% goal. This bill will inevitably drive large electricity emission reductions in coming years, making it even more important to focus on natural gas and transportation emission reductions.

Our 2030 goal will be difficult to meet, if nearly impossible, but we need to do everything we can to do so. We urge every public institution and the business community to commit to this ambitious goal and work together—and with us—to achieve it.

The latest report from the Intergovernmental Panel on Climate Change (IPCC) warns that the window of opportunity to avert the worst impacts of climate change is rapidly shrinking (IPCC, 2021). Globally, we have already reached 1.1°C of temperature increases (Associated Press, 2021), and without immediate reductions in human-caused climate pollution, it is likely Earth will exceed 1.5°C of warming before 2030 (World Meteorological Organization, 2022).

We are seeing increasing numbers of high heat days, extreme weather events, and wildfires. The threats to our natural and human systems are growing more complex as these factors combine.

These climate impacts place an emotional and financial toll on community members and create an enormous price tag for local governments. Boulder County has been in a continuous state of disaster recovery since the 2010 Fourmile Canyon Fire, which signaled the beginning of increased wildfire activity across the county. Damages from the catastrophic 2021 Marshall Fire totaled more than $2 billion, with 6,200 acres burned and over 1,000 structures completely destroyed.

Over the centuries since the Industrial Revolution, human activities have dramatically increased the amount of greenhouse gases (GHGs) in the atmosphere. These gases trap heat in the atmosphere, which at pre-industrial levels allowed life on Earth to flourish. However, such a rapid rise in GHG concentrations has disrupted these climate conditions and threatens to increase temperatures to dangerously high levels.

Communities can track whether their GHG emission levels are decreasing, staying constant, or increasing through a GHG inventory, so that we can all work towards solving the climate crisis.

Addressing climate change is a huge undertaking. One of the most important steps is to decrease, and eventually eliminate, the greenhouse gas (GHG) emissions that are driving the climate crisis. This process, also called mitigation, can be difficult to track without data, which is why local governments conduct GHG inventories every few years to understand our baseline and track progress towards our goals.

Boulder County’s GHG emissions inventory quantifies our emissions countywide, as well as by community and sector. With this information, we can understand the largest sources of carbon emissions and take focused action to drastically reduce our emissions. This webpage shows the results of our geographic-based inventory (also called sector-based inventory), but also pulls in some important results from a first-ever-completed-in-Colorado consumption-based emissions inventory.

The inventory protocol used is the Global Protocol for Community-based Greenhouse Gas Emissions Inventories (GPC) and it is a globally-recognized process and standard designed for cities and counties to account for and report GHG emissions. The inventory shows emissions that occurred in 2021.

The inventory classifies emissions by Scope 1, Scope 2, and Scope 3 emissions. Scope 1 emissions reflect the emissions generated within the county’s boundary, including natural gas consumption in buildings, gasoline and diesel fuel use for transportation, refrigerant use and cement production, agriculture and other land use, and oil and gas well leaks. Scope 2 emissions reflect emissions resulting from the use of grid-supplied electricity. Scope 3 emissions reflect out-of-boundary emissions such as those resulting from waste and wastewater treatment, electricity transmission and distribution losses, and transboundary transportation such as aviation.

There are other sources of Scope 3 emissions but those are not included in this inventory. The figure below shows how emissions are classified into the Scope 1, 2, and 3 categories and defines which emissions are included in the Boulder County GHG inventory.

To create its inventory, Boulder County counts all the emissions created within its political borders. Another way to look at the emissions generated within Boulder County is at the municipal level. You can see the emissions generated in eight different municipalities in Boulder County as well as in unincorporated Boulder County:

• City of Boulder

• Town of Erie*

• City of Lafayette

• City of Longmont*

• City of Louisville

• Town of Lyons

• Town of Nederland

• Town of Superior

The unincorporated category includes the Towns of Jamestown and Ward.

*Note: A few municipalities have land area in more than one county. Only the Boulder County portions of these municipalities are included in this inventory.

For additional information on individual communities, a few Boulder County municipalities such as the City of Boulder conduct their own inventories. However, the data and information presented here will only reference Boulder County’s inventory. 

Boulder County also completed the first-ever Consumption-Based Emissions Inventory (CBEI) in Colorado. A CBEI is an estimate of the GHG emissions associated with the activity of all residents of a geographic area. It's equivalent to a personal household carbon accounting tool but scaled to all households within Boulder County. The CBEI for Boulder County will enable the county to understand the emissions that may occur anywhere in the world—directly or indirectly—as a result of the activities of Boulder County residents. You can find out more about the CBEI by clicking  here .

CBEIs differ from traditional sector-based greenhouse gas inventories. In traditional sector-based or "geographic" inventories, a county would look at all emissions that occur within the county’s borders. In contrast, CBEIs consider emissions that may occur anywhere in the world, as long as they are directly or indirectly a result of the activities of the residents of the county.

The visual  below  helps illustrate the differences between the sector-based and consumption-based inventories.

Boulder County and municipalities have climate goals to transition to a low-carbon future and a clean energy economy. Boulder County has bold goals to reduce countywide emissions 80% from 2021 levels by 2030 and achieve carbon neutrality by 2035.

In the last five years, since 2016, we’ve reduced emissions 16%. To meet our 2030 goal, we need to more than triple the rate of emissions reduction in the next 8 years (2022-2030), and drastically decrease from 12 mt CO ₂ e per person to 2 mt CO ₂ e per person.

For Boulder County to reach its targets, it needs the help of each municipality. For municipalities to reach their goals shown below, they also need the help of the county. This underscores the collaborative nature of climate action and the need for all hands on deck!

Reducing GHG emissions 80% by 2030, according to the most aggressive local government climate and science-based target, is going to be tough to achieve. We urge every public institution and the business community to commit to this ambitious goal and work together—and with us—to achieve it.

In 2021, Boulder County produced 4.1 million mt CO ₂ e. To best target its efforts to mitigate the impacts of climate change and meet its ambitious emissions reduction targets, Boulder County analyzed its greenhouse gas (GHG) data and inventory results in a number of different ways.

One helpful way to understand our emissions is to look at emissions by sector from the GHG inventory. Breaking down an inventory by sector helps visualize the high-level distribution of emissions and compare major trends across municipalities and other jurisdictions. Boulder County categorizes its GHG data into seven commonly-used sectors, shown in the graph.

For Boulder County, the sectors with the highest emissions include:

• Energy Use in Buildings (Residential and Commercial): 64%
• Transportation: 26%
• Industrial Processes and Product Use (IPPU): 7%
• Other sectors each make up 2% or less.

Over 90% of our GHG emissions in Boulder County result from burning fossil fuels for building energy use and for transportation.

The building energy use sector combines all the energy sources used to power buildings. Electricity, natural gas, stationary diesel, and propane used for heating, cooling, and general building operations account for 64% of Boulder County’s total emissions. Within specific communities, the number varies but typically still dominates total emissions. Within this sector, electricity and natural gas make up the majority of emissions.

The transportation sector refers to any piece of machinery that moves, including automobiles, airline travel, railways, and transit. In Boulder County, this sector accounts for 26% of emissions. The majority of the sector’s emissions come from gas-powered vehicles, followed by aviation fuel and diesel-powered vehicles.

Emissions by sector are further broken down in the following figure:

Agricultural emissions include all the off-gassing from livestock, manure, pesticides and fertilizers, and soil management. They account for 0.2% of Boulder County’s total emissions. Only unincorporated Boulder County produces significant emissions in this sector; the largest sources within the sector are enteric emissions, manure management, and soil management.

The waste and wastewater sectors produce emissions largely from the decomposition of materials in landfills and wastewater treatment processes. These processes release methane and nitrous oxide, both much more potent greenhouse gases than carbon dioxide. In Boulder County, these sectors, which also include compost, combine to about 2% of Boulder County’s total emissions. The decomposition of waste is the largest source at approximately 91% of total waste emissions.

Oil and gas production and IPPU (Industrial Processes and Product Use) emissions make up approximately 7% of Boulder County’s greenhouse gas emissions. These industrial sectors include any emissions resulting from industrial processes within the county’s borders, refrigerant leaks, oil and gas wells, and oil and gas production. Of these sources, IPPU comprises the largest share at 85% and includes emissions from the cement manufacturing plant outside Lyons. In Boulder County, most oil wells are located in unincorporated Boulder County with a few operating in Erie and Lafayette.

Another helpful way to understand our emissions is to look at emissions by source from the GHG inventory. The GHG inventory identifies the largest emitting sources, as shown in the previous figure. Using this information, Boulder County can focus on the most important policies and strategies to maximize reductions from the largest emissions sources.

Boulder County’s top emitting sources include:

• Electricity

• Natural Gas

• Mobile Gasoline

The GHG emissions inventory for Boulder County quantifies all the GHG emissions caused by human activities county-wide as well as emissions in each community in Boulder County. In the dashboard below, you can see the emissions generated in eight different municipalities in Boulder County as well as in unincorporated Boulder County. With this information, the communities in Boulder County can understand the largest sources of carbon emissions and take focused action to drastically reduce our emissions.

Boulder County is diverse in terms of rural and urban communities and other community characteristics. Urban communities can have lower per capita emissions due to density in population, services, and other emission-generating activities. On the other hand, members of more rural communities may have to drive longer distances and rely on older energy infrastructure.

Given these factors, the community with the largest per capita emissions in 2021 was unincorporated Boulder County and the lowest per capita was Superior. With the exception of these two, the rest of the communities included in the county inventory all generated emissions per capita between nine and 11 mt CO ₂ e.

In the dashboard below, the inventory results can be filtered by community.

In 2021, Boulder County recorded a 16% overall reduction of greenhouse gas (GHG) emissions from 2016 levels.

At the sectoral level, the most significant reductions came from the energy use sector and the transportation sector. In the energy use sector, the key source that drove reductions was electricity, which saw a 20% decline. In the transportation sector, mobile gasoline, mobile diesel, and aviation had the largest impacts on reductions.

While overall emissions came down, some sources showed an increase between 2016 and 2021, most notably natural gas with an 11% increase.

Analyzing municipal-level data revealed that all communities had reductions in GHG emissions ranging from 7% to 25% from 2016 to 2021. When assessed on a per capita basis, the Cities of Boulder, Longmont, and Lafayette had the greatest reductions in per capita emissions from 2016 to 2021. Emissions from electricity, mobile gasoline, mobile diesel, and aviation decreased in all communities across the county.

The City of Boulder, the Town of Nederland, and the Town of Superior led the way with the following reductions in their respective community emissions from 2016 to 2021.

• City of Boulder: 25% reduction
  • These reductions were largely driven by electricity (down 33%), mobile gasoline (down 40%), mobile diesel (down 57%) and aviation (down 54%).
• Town of Nederland: 23% reduction
  • These reductions were largely driven by electricity (down 34%) and aviation (down 56%).
• Town of Superior: 19% reduction
  • These reductions were largely driven by electricity (down 19%), mobile gasoline (down 25%), and aviation (down 54%).

Boulder County is a nationally recognized leader in climate action, committed to taking bold steps toward a climate-resilient and just future.

Yet, Boulder County is falling short of its climate targets. Boulder County as well as other municipalities, public institutions, and the business community must do more to address climate change and do so quickly.

Find out how you can address climate change by visiting the climate action website (coming soon) and in the Boulder County 2023 Sustainability Plan available  here . 

• Each section of this StoryMap is listed in the header bar above and describes a different aspect of Boulder County’s emissions inventory process and approach to combating climate change. Click on the section title in the header bar to skip to a specific section.
• Text that is  underlined in green  is linked. Click on a hyperlink to learn more.
• Boulder County is using maps to tell a story about our climate action. All maps have legends in the lower-left corner. Click to expand them.
• Dashboards display a variety of information in a digestible format, helping us understand the complex emissions story in Boulder County. Hover over the dashboards and click on them to interact.
• Click on each municipality in the Goals section to read goals one at a time. To exit, click on the floating "X" in the bottom left corner.

• Climate: Climate is the long-term pattern of weather conditions in a particular location.
• Global Protocol for Community-Scale Greenhouse Gas Emission Inventories (GPC): A globally-accepted, standardized accounting framework for municipalities and other jurisdictions to calculate and report their greenhouse gas emissions.
• Global Warming Potential (GWP): This concept refers to how much heat that a greenhouse gas will trap over a standard period of time relative to carbon dioxide. It helps us compare the warming impact that different gases have in the atmosphere and calculate total emissions across different gases.
• Greenhouse gases (GHGs): These gases trap heat in the earth’s atmosphere, changing the climate.
• Metric tons of carbon dioxide equivalent (mt CO ₂ e): This refers to a common unit used to measure total GHG emissions. It is helpful to convert different GHGs, which may have different atmospheric warming potentials, to CO ₂ e so we can easily compare their impact on the climate.
• Scope 1 Emissions: These emissions are generated within the county’s boundary, including natural gas consumption in buildings, gasoline and diesel fuel use for transportation, refrigerant use and cement production, agriculture and other land use, and oil and gas well leaks.
• Scope 2 Emissions: These emissions result from the use of grid-supplied electricity.
• Scope 3 Emissions: These emissions reflect out-of-boundary emissions such as those resulting from waste and wastewater treatment, electricity transmission and distribution losses, and transboundary transportation such as aviation.

IPCC (2021): “ Summary for Policymakers .” In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change.

Associated Press (2021): “ Scientists give Earth a 50-50 chance of hitting key warming mark by 2026 .” National Public Radio.

World Meteorological Organization (2022):  "Global Annual to Decadal Climate Update, Target years: 2022 and 2022-2026." Royal Meteorological Society.