Sitka Community Renewable Energy Strategy

Greenhouse Gas Emissions Inventory

2023 Sitka GHG Emissions Inventory(PDF, 15MB)

Summary

Emission Source End Uses

About Greenhouse Gas Emission Inventories

What are Greenhouse Gases?

Solar radiation from the sun warms the Earth’s surface, which in turn releases heat back into the atmosphere. Some of that heat leaves the atmosphere and dissipates into space, but some is absorbed and re-emitted by certain gases in the atmosphere, trapping the heat in the atmosphere. This is known as the greenhouse effect¹.

Greenhouse gases (GHG) are gases that contribute to this heat trapping effect. Many of these gases occur naturally in the atmosphere; however human activities that emit GHGs are responsible for increases in concentrations. This phenomenon is known as global warming, which plays a significant role in broader climate changes caused by human activities that rely on fossil fuels.

Not all GHGs are the same. Some GHGs are more effective at trapping heat. GHGs can remain in the atmosphere for different lengths of time, from just a few years to thousands of years. Global Warming Potential (GWP) is used to compare GHGs heat trapping capabilities compared to one ton of CO₂ over 100 years.

The Greenhouse Gas Effect. Increased GHGs means less heat from the sun escapes the atmosphere.

How Greenhouse Gases Warm Our Planet. AR6 values, IPCC Sixth Assessment².

Greenhouse Gases and the Carbon Cycle

The carbon cycle (yellow) is a naturally occurring process that influences the climate. However, human activity is currently adding more carbon than the cycle can handle, increasing the amount of carbon in the atmosphere which warms the planet.

Graphic by University of California Berkley Museum of Paleontology.

¹U.S. Environmental Protection Agency (EPA) Overview of Greenhouse Gases Website: https://www.epa.gov/ghgemissions/overview-greenhouse-gases.

²IPCC. 2023.Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, H. Lee and J. Romero (eds.)]. IPCC, Geneva, Switzerland, pp. 35-115, doi:10.59327/IPCC/AR6-9789291691647.

What is a Greenhouse Gas Emissions Inventory?

Greenhouse gas (GHG) emissions inventories consider human activities associated with GHG emissions and estimate the quantity of those emissions from those activities. They are a tool to help communities understand where their energy comes from and where it goes. Greenhouse gas inventories can measure the amount of emissions released at any scale, like from a single home, operations of a business, an entire industry, or whole areas based on local, state, or national boundaries.

The amount of energy used and what it is used for is also known as an energy baseline. Since most human actives use energy from fossil fuel sources, a common way to estimate energy baselines is by measuring the amount of GHG emitted by human sources within a defined boundary over the course of a year.

Why do you Inventory Greenhouse Gas Emissions?

Currently, fossil fuels are necessary in our society. While non-fossil fuel sources of energy are becoming more available every day, everyone directly or indirectly requires fossil fuels for daily life. It is important to remember that GHG emission inventories are a snapshot in time and reflect the level of technology available and should inform strategies that enhance energy independence and reduce harm to people and the environment — keeping the focus on solutions, not fault-finding.

GHG inventories serve as an energy baseline for a community and are essential for energy planning. They provide a comprehensive snapshot of local emissions, energy needs, and other information that can help individuals, organizations, and local government leaders prioritize actions and make informed decisions about their energy use. These inventories can be used to identify reduction targets and effective strategies for reducing emissions, they can also track increases and decreases in future emissions.

With a Greenhouse Gas Emissions Inventory, goals can be set and accomplished strategically.

Example Target Goal:
A community that emits 100,000 MTCO₂e every year wants to reduce their overall emissions by 50% by 2050.

The community can try to cut its emissions by 50% equally across all sources…

…or it can strategically target categories that are important to its livelihoods, have available technology, or are easy to reduce.

The Greenhouse Gas Emissions Inventory Process

Since GHG emission inventories are useful for all sorts of purposes. Standards exist to help inventories remain consistent and comparable. Generally, the process to create a GHG emissions inventory is conducted in the following phases and steps:

GHG Emission Inventory Development Phases

Scope and Plan

1. Define the Purpose, Boundaries, and Timeframe

The purpose of an inventory varies depending on the kind of organization requesting the inventory. Similarly, the boundary of an inventory can range from a single business or industry to a larger community, covering the emissions released by all human activities that occur within the boundaries of a city, town, or county. The team conducting the inventory selects a timeframe, typically a year. Since information necessary for the inventory might take time to be published, the chosen year is often a few years prior to when the inventory is conducted.

2. Choose Methods and Standards

The methodologies used and standards followed should be based on the purpose or specific activities in an inventory, availability of data, and consistency with a country’s national inventory and/or other measurement and reporting programs. The Greenhouse Gas Protocol for Cities³ is the most widely used standard and guidance for governments, cities, and corporations for tracking emissions in their jurisdictions. The protocol includes methodologies and formulas necessary to calculate the total emissions of selected Scopes.

3. Decide the Scope

GHG emissions are commonly classified into three scopes, which are used to help categorize and track emissions.

Categories of Greenhouse Gas Emissions

Visualization of the three Scopes of GHG emissions, based on Scope and whether they are emitted directly or indirectly. Adapted from the GHG for Cities³

The GHG Protocol for Cities defines those Scopes as:

Scope	Definition	Direct/Indirect
Scope 1 Burn	GHG emissions from sources located within the city boundary.	Direct
Scope 2 Buy	GHG emissions occurring due to the use of grid-supplied electricity, heat, steam and/or cooling within the city boundary.	Indirect
Scope 3 Beyond	All other GHG emissions that occur outside the city boundary as a result of activities taking place within the city boundary.	Indirect
Definitions of Scopes for cities’ GHG emissions, as defined by GHG Protocol for Cities with descriptions from the World Resources Institute

Most community-wide inventories include Scopes 1 and 2, and may include some Scope 3 emissions, depending on the purpose of the inventory and data availability. Frequently, Scope 3 is omitted because there is not enough high-quality data that is readily available. Fortunately, the GHG Protocol allows reporting of GHG emissions in a variety of formats depending on the purpose and audience.

Scope 1

Also known as direct emissions, Scope 1 emissions include all GHG emissions from the heating and cooling of residential and non-residential building as well as transport of people and freight occurring within a city's boundaries. A shorthand for Scope 1 emissions is burn, because it includes things a community burns. Scope 1 emissions can be broken down further into:
	Stationary combustion: Fuel, like oil and gas, burned in buildings or equipment in the community. Think boilers and other fuel-powered machinery that does not move and is used for industrial processes.
	Mobile combustion: Fuel used for vehicles and mobile equipment like cars, trucks, and other gas-powered tools within a geographic boundary.
	Fugitive emissions: Refrigeration chemicals released from air conditioning and fire suppression chemicals used in building fire suppression systems or equipment like fire extinguishers.

Scope 2

The shorthand to remember Scope 2 is buy because this scope includes emissions from the energy purchased to run things like heating, cooling, and home appliances. These are considered indirect emissions because in many communities, electricity is generated from fossil fuel sources, often outside the boundaries of a city and delivered via transmission powerlines. Scope 2 emissions are often one of the biggest emission sources for communities, which is why many strategies emphasize saving electricity or installing renewable generation sources.

Scope 3

Scope 3 emissions are indirect emissions from activities that support a community but are not necessarily within a community's boundaries. That is why they are emissions beyond the control of a community but still benefit the community. Scope 3 emissions are the most challenging to find good data for calculations, are challenging to regulate, and are therefore often excluded in GHG emissions inventories. However, understanding Scope 3 emissions help community members make informed decisions about their daily lives. The extent of inclusion of Scope 3 emissions depends on the purpose of the inventory.

Scope 3 emissions can be further categorized into:

Upstream emissions come from moving a good or person to a place, or the emissions in creating a product.

Downstream emissions come from disposing of a product or moving people from a place.

³Greenhouse Gas Protocol. 2022. GHG Protocol for Cities. https://ghgprotocol.org/ghg-protocol-cities

Collect Data and Quantify Emissions

4. Collect Information

Information on energy use in the residential, commercial, and industrial sectors, as well as solid waste, water use and treatment, as well as transportation occurring within the defined boundary are collected from a variety of sources. However, in some cases, data is not available for all sectors. Depending on the scale and Scope needed, government agencies, researchers or other organizations work with a variety of local partners. Such partners may include local utilities, regional transit authorities, and local businesses to collect data to create estimates.

5. Create Informed Assumptions to Fill Data Gaps

Data gaps frequently occur in GHG emissions inventories, especially for larger-region inventories and Scope 3 emissions where data availability is less consistent or boundaries are less clear. In these cases, assumptions, or numbers derived from available information and research, are used to fill data gaps. Assumptions in GHG reports are common, especially for harder-to-track sectors, such as marine and air travel. Fortunately, GHG inventories are a living document and can be updated as new information or more accurate data becomes available. This inventory should be updated accordingly.

6. Calculate Emissions Using Emission Factors

Once all the information is gathered, the total emissions can be calculated based on either the quantity of fuel used in an area, estimated amount of activity, or a combination of both. Since not all fuels produce the same amount or kind of emissions and the fuel efficiency can vary from activity to activity, emission factors are used. Emission factors, or emissions per activity unit, are numbers published by the U.S. Environmental Protection Agency’s (EPA) and can be found on the EPA GHG Factor Hub⁴. These emissions factors may be occasionally updated as more scientific research is done.

7. Validate Estimations

Since almost all data sources and activity data have limitations, comparing multiple forms of data helps improve the accuracy of the inventory. By cross-referencing estimations with multiple sources, areas of improvement can be identified, further researched, and updated to better reflect reality. In many cases, data validation includes a combination of research and community input and requires back and forth collaboration to determine a reasonable level of accuracy. The accuracy of an estimate is indicated by a level of confidence. Estimates with high confidence are considered very accurate while estimates with lower confidence may benefit from some updates which may or may not significantly change the estimate.

⁴Environmental Protection Agency (EPA). 2024. EPA Emissions Factors. https://www.epa.gov/system/files/documents/2024-02/ghg-emission-factors-hub-2024.pdf.

Report, Update, and Track Progress

8. Report Emissions Findings

Emissions are reported in metric tons of carbon dioxide equivalent (MTCO₂e), which is the standard unit for GHG emission reports. Since some GHGs are more effective at trapping heat and remain in the atmosphere for longer periods of time, the Intergovernmental Panel on Climate Change (IPCC), publishes conversions of all GHGs to the global warming potential of one metric ton of carbon dioxide (CO₂) over 100 years². By converting all GHG to MTCO₂e, other GHGs like methane (CH₄), and nitrous oxide (N₂O) can be compared side-by-side. This also has the benefit of enabling comparison between emissions categories that emit different kinds gases either within the inventory or with other GHG emission inventories.

ONE METRIC TON OF CARBON DIOXIDE (MTCO₂e)

has the same global warming potential as:

Examples of one Metric Ton of Carbon dioxide equivalent

9. Use the GHG Inventory to Set Goals

GHG emission inventories are a tool that provides a comprehensive snapshot where energy comes from and where it goes. Since a GHG emission inventory is a tool, it does not include recommendations for action. However, the information in the inventory can help individuals, organizations, and local government leaders prioritize actions and make informed decisions about their energy use. It can be used to identify reduction targets and effective strategies for reducing emissions and track increases and decreases in future emissions.

10. Update and Track Progress on Goals

GHG inventories are a living document and can be updated as new information or more accurate data becomes available. This inventory should be updated accordingly. Additionally, once goals are set, updating the inventory helps track progress on meeting those goals. The frequency of the updates typically ranges between every five to ten years and should be determined based on the kinds of goals set and when a community hopes to accomplish them.

³Greenhouse Gas Protocol. 2022. GHG Protocol for Cities. https://ghgprotocol.org/ghg-protocol-cities.
⁴Environmental Protection Agency (EPA). 2024. EPA Emissions Factors. https://www.epa.gov/system/files/documents/2024-02/ghg-emission-factors-hub-2024.pdf.
⁵Velthof, G.L., Kuikman, P.J. & Oenema, O. 2023. Nitrous oxide emission from animal manures applied to soil under controlled conditions. Biol Fertil Soils 37, 221–230. doi:10.1007/s00374-003-0589-2.

About Sitka's Greenhouse Gas Emission Inventory

About Sitka's Greenhouse Gas Emissions Inventory

The purpose of this inventory is to quantify GHG emissions for the entire community and serve as an energy baseline for Sitka. It can be used for future energy planning efforts, goal identification, and progress tracking for emission reduction, improving energy independence, or simply better understanding how Sitka uses energy. As an energy baseline, this document does not make any policy recommendations.

Based on available data, the chosen baseline year for Sitka’s inventory is 2023, though some data sources are from 2021 or 2022. While the best available information was used at the time of this report, amounts, figures, and statistics can be updated as new data become available.

Who Prepared Sitka’s Greenhouse Gas Emissions Inventory?

Sitka’s GHG emissions inventory was prepared as part of the City and Borough of Sitka’s (CBS) Sitka Community Renewable Energy Strategy (SCRES) project, supported by the 2023 cohort of the Department of Energy’s Energy Technology Innovation Partnership Project (ETIPP), focused on aiding remote and islanded communities that are interested in creating a more reliable, affordable, and efficient energy system. Through ETIPP, CBS partnered with the Pacific Northwest National Laboratory (PNNL). Throughout the process, PNNL was guided and advised by the CBS Sustainability Commission to ensure the inventory accurately reflected the unique needs of Sitka and that assumptions were based on local data that was as accurate as possible.

In this report, the term “Sitka” indicates the community at large, “CBS” indicates the local municipality which includes the municipally owned electric utility, and “Sitka Sustainability Commission” indicates the group of local community members appointed to a city board to advise CBS on matters of sustainability.

Who Prepared Sitka’s Greenhouse Gas Emissions Inventory?

Sitka’s GHG emissions inventory was conducted iteratively over two years following the Greenhouse Gas Protocol for Cities with modifications to better capture the nuances of an islanded community like Sitka. Throughout the process, PNNL was guided and advised by the CBS Sustainability Commission and public comment to ensure the inventory accurately reflected the unique needs of Sitka and that assumptions were based on local data that was as accurate as possible.

Sitka’s GHG Inventory was Built Iteratively and Collaboratively

The working relationship between PNNL, the Sustainability Commission, and the public.

Key Actions and Approvals

Timeline of actions and steps to prepare this inventory.

The Scope of Sitka's Greenhouse Gas Emissions Inventory

Sitka’s categories of GHG emissions differ from standard methodologies

Sitka's GHG Inventory Challenges

	Sitka does not have clear boundaries for some emission sources As a remote, islanded community, Sitka does not have clear boundaries that are typically used in GHG emission inventory methods. While land-based emissions are much easier to calculate as the sources have clear boundaries, many Scope 3 sources are minimally included or excluded in community-wide inventories, but for islanded communities, the role of Scope 3 emissions sources are critical and important to understand and include. Sitka’s emissions sources are not necessarily confined to its land and Sitka is generally more reliant on indirect, Scope 3 sources. Indirect, Scope 3 emissions presented a set of challenges for creating an inventory that is representative of Sitka’s unique lifestyle while remaining helpful, accurate, and not overly broad. To address this, many boundaries used for Sitka were created based on the emission source, available information, and community context provided by the Sustainability Commission and by the public.
	Sitka is only accessible by plane or boat As an islanded community, residents and visitors can only arrive by plane or boat. As Scope 3 sources, these emissions are difficult to calculate as they are often linked to information that is considered proprietary and not publicly available.
	Sitka relies on shipping for goods and waste disposal Since nearly all goods arrive in Sitka via barge, these emissions are important to include in the inventory. However, there is no standard way to calculate this. Similarly, Sitka does not have a landfill that accepts most municipal solid waste. Instead, waste is shipped south to Seattle, where it is then taken to the Roosevelt landfill in Southeastern Washington.
	Sitka is not connected to a regional electric grid All electricity used in Sitka is generated locally by the Blue Lake and Green Lake Hydroelectric Projects, which means electricity generation falls in Scope 1, not Scope 2. There is no connection to a larger regional grid, so Scope 2 does not apply to Sitka. Nearly 100% of electricity in Sitka is renewable and does not emit greenhouse gases. That is good for the total emissions in Scope 1 and means Scope 2 does not apply. In many community GHG emissions inventories, Scope 2 is the largest contribution to the total emissions, depending on the available renewable energy resources.
What does Sitka’s GHG Emissions Inventory NOT Include?
	Natural Process that Emit or Absorb Greenhouse Gases GHG emission inventories are designed to capture emissions from unintentional human behavior. As such, this inventory does not include natural processes like trees removing CO₂ from the atmosphere (carbon sequestration) or other non-human emission sources such as decomposition of materials or other natural processes. The Tongass National Forest stores the most carbon of any U.S. National Forest⁶. While various policies and practices have established ways of quantifying and crediting individuals or organizations for reforestation or forest protection, these methods of crediting are not standard in greenhouse gas inventories. This is especially true when the land in question is not managed or designed intentionally for carbon sequestration. In short, we do not credit Sitka for what the trees do, but that’s okay!
Outline of the Carbon Cycle (Yellow) The carbon cycle (yellow) is a naturally occurring process that influences the climate. Human activity is currently adding more carbon than the cycle can handle, increasing the amount of carbon in the atmosphere which warms the planet. Graphic by University of California Berkley Museum of Paleontology.
	Fugitive Refrigerant Emissions Refrigerants are fluorinated gases (F-gases) that, for the most part, are created by humans and do not occur in nature. Many residential and industrial technologies use refrigerants in refrigerators, air conditioners, industrial ice production facilities, and data centers. Due to the high warming potential (GWP) of refrigerants and the length of time they remain in the atmosphere, the small volume of direct emissions that are released accounts for approximately 1% of U.S. emissions⁷. In theory, refrigerants can be collected from machinery and reused, however this does not often happen because the costs of recovering refrigerants currently outweigh the potential revenue from resale.
How Greenhouse Gases Warm Our Planet. AR6 values, IPCC Sixth Assessment²
	Refrigerant emissions are not included in this inventory, primarily due to the difficulty and uncertainty of quantifying those emissions. Ideally, a refrigerant is contained within the technology where it exists. However, technologies using refrigerants are prone to leakage or improper disposal, which leads to the refrigerants being released into the atmosphere. This leakage is the main source of direct emissions and therefore is extremely difficult to quantify and track. That said, refrigerants are still abundant in Sitka, especially in the technologies used by the seafood processing industry. Any steps taken to make seafood processing more efficient or to prevent refrigerant leakage in the industry could lead to decreased emissions. Similarly, the shipping of goods that require refrigeration is another major source of refrigerant emissions. After fishing vessels, refrigerated bulk carriers are responsible for the highest amount of refrigerant emissions for refrigeration (but not for air conditioning) compared to other ships globally⁸. In 2018, refrigerated containers accounted for 18.2 million MTCO₂e worldwide.
²IPCC. 2023.Climate Change 2023: Synthesis Report.Contribution of Working Groups I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, H. Lee and J. Romero (eds.)]. IPCC, Geneva, Switzerland, pp. 35-115, doi:10.59327/IPCC/AR6-9789291691647. ⁶Barrett, T., M. 2014. Storage and flux of carbon in live trees, snags, and logs in the Chugach and Tongass national forests. General Technical Report. PNW-GTR-889. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. https://research.fs.usda.gov/treesearch/45431. ⁷Environmental Protection Agency (EPA). 2024. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2022 EPA 430R-24004. https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2022. ⁸International Marine Organization. 2020. Fourth Greenhouse Gas Study. https://wwwcdn.imo.org/localresources/en/OurWork/Environment/Documents/Fourth%20IMO%20GHG%20Stud y%202020%20%20Full%20report%20and%20annexes.pdf.

How Sitka's Emissions Were Calculated

Throughout the process of conducting this inventory, the technical experts worked to find the best available data to create estimates for each emission source. In addition to guidance from the Greenhouse Gas Protocol for Cities3, calculations were shaped by feedback from the Sustainability Commission and public input. Assumptions were iterated upon to improve the estimates as new information became available, and they were validated as much as possible through comparison with available data.

In General, Two Kinds of Data Were Used to Create Estimates

Fuel imports were used to calculate the quantity of emissions from different fuel types that arrive in Sitka and activity data was used to break down how that fuel was used in Sitka by sectors and sub-sectors. Breaking fuel and emissions down into finer resolution categories helps determine which policy mechanisms or community actions could have the highest impact to achieve goals.

Fuel Imports		Activity Data
Pros	Quantifies different types of fuels Works well for land-based emission sources	Pros	Uses well researched emission factors for each fuel type Activities like wastewater treatment have standardized calculations Customizable for specific sources
Cons	Doesn’t specify what the fuel types are used for Can be inconsistent year-to-year Doesn’t account for fuels brought in from other locations (a boat refueled in Juneau and traveling to Sitka)	Cons	Requires additional information to determine accurate activity levels, especially for small communities Some necessary information is not publicly available, especially if it is related to a business’s operation

Fuel Imports

U.S. Army Corps of Engineers’ (USACE) 2022 5-Year Cargo Report for Sitka Harbor⁹ is a record of all shipments in and out of the city, including fuels, which are broken into categories of gasoline, kerosene, distillate fuel oil, residual fuel oil, hydrocarbons and petrol gases, and “petro products” not elsewhere counted (NEC). If we were to assume the amount of fuel burned is the same as the amount of fuel imported, emission estimates from burning fossil fuels using the Cargo Report would be simple. However, due to both fluctuations in the Cargo Report data from year to year and some issues with data quality, this is not the only data source relied upon. Instead, a combination of Cargo Report data and activity data is used.

⁹U.S. Army Corps of Engineers (USACE). 2022. 5-Year Cargo Report: Sitka Harbor. https://ndc.ops.usace.army.mil/wcsc/webpub/#/report-landing/year/2021/region/4/location/4808.

Activity Data

Activity data is data that allows us to estimate how often certain emissions-related activities take place in Sitka. Using activity data, emissions are calculated from the ground up by estimating how often certain activities take place and what levels of emissions are caused by those activities. Each emission source’s activity data comes from a variety of sources with a variety of uncertainties, which are outlined in each section.

Breaking fuel and emissions down into specific categories helps determine which policy mechanisms or community actions can have the highest impact in reducing emissions. Policy mechanisms can include incentivizing building energy efficiency measures and electrifying vehicles, buildings, or boats. For example, understanding the emissions tied to heating residential housing can determine the emissions impact of incentivizing home electrification measures.

In 2022, Sitka imported an estimated...

For simplification, this report uses the term diesel in place of “Distillate Fuel Oil”, which includes diesel used for transportation and heating (Diesel #1 and #2). Most of the fossil fuel imported to Sitka is diesel.

⁹U.S. Army Corps of Engineers (USACE). 2022. 5-Year Cargo Report: Sitka Harbor. https://ndc.ops.usace.army.mil/wcsc/webpub/#/report-landing/year/2021/region/4/location/4808.

Limitations

How Accurate is Sitka’s Greenhouse Gas Emissions Inventory?

GHG inventories are a strategic tool and are not 100% accurate, nor do they have to be. While some information necessary for developing GHG emissions inventories is readily available, other information is not as easy to obtain. While doing additional research may improve some estimates, the improvements are often small compared to the resources needed to create the most accurate inventory possible.

Sitka’s GHG emissions inventory uses a combination of commonly used data sources and community sources, such as data from CBS departments and surveys, or local organizations with expertise. Where data gaps remained, assumptions were created based on CBS Sustainability Commission feedback and public comment. Throughout the report, the confidence of an emission estimate is clearly stated.

What are Assumptions?

Gaps in data are a challenge in conducting a GHG emissions inventory, especially for larger-region inventories where data availability is less consistent. Assumptions, or numbers derived from available information and research, are used to fill data gaps. Assumptions in GHG reports are common, especially for harder-to-track sectors, such as marine and air travel. Fortunately, GHG inventories are a living document and can be updated as new information or more accurate data becomes available. This inventory should be updated accordingly.

Confidence Levels

How do you know how accurate a GHG emission estimate is?

For this inventory, each estimate includes the inputs used to create the assumptions that were used to calculate the emissions and the data sources. These data sources were ranked based how detailed they were, and the kind of information provided. Once all the sources were ranked, the overall emissions category was also ranked based on the quality of the inputs. If they fell between levels, the score was rounded down to the lower confidence level.

Confidence Level	Rationale
Great	Values with this ranking use values that are unlikely to need to be adjusted in the future, except in response to major community changes or changes to scientific understanding. Datasets used were specific to Sitka and contained detailed information or were not dependent on Sitka-specific data. EPA emission factors are an example.
Good	Values used may be specific to Sitka but may have been aggregated and some detail obscured, or the inputs are research-based and adapted to Sitka based on additional information and community input if provided. While more information would improve the estimate, the overall impact would likely be small, and these inputs are still justifiable with a general understanding.
OK	The value was not specific to Sitka. Additional, better, or more local data could improve the estimate, but the overall impact would likely be small unless additional inputs were also changed. These inputs are still justifiable with a general understanding.
Poor	Information was likely unavailable or too obscure to be useful for creating the input. More or better data could improve the estimate, and the overall impact could be meaningful to the category.

Questions? Contact

This page was last updated January 30, 2026