Washington's greenhouse gas inventory
The greenhouse gas inventory estimates Washington’s total emissions using many datasets from every sector of the economy. It’s our official tool for tracking progress toward our state's legal limits on greenhouse gas emissions.
In 2026, Ecology began publishing inventories every year, as opposed to every two years, in an effort to get more current data to lawmakers and the public. The next inventory will be published by December 2026.
The inventory is designed to measure the collective impact of Washington’s climate policies and reveal long-term trends.
Washington’s emissions peaked more than a quarter-century ago in 2000. Between 2000 and 2022, emissions fell 12.4%. In that same time, the state's population grew by a third and its gross domestic product nearly doubled.
The long-term trend tells that the state’s emissions decoupling from economic growth, something we expect to continue as the state’s continues implementing its suite of climate policies.
Greenhouse gas inventories
Our most recent inventory shows that Washington's greenhouse gas emissions declined 0.5% from 2021 to 2022, following a partial rebound from 2020 to 2021 after the pandemic.
- 2022 total emissions — 96.1 million metric tons
- 2021 total emissions — 96.6 million metric tons
- 2020 total emissions — 89.2 million metric tons
- Washington State Greenhouse Gas Emissions Inventory: 1990–2021
- Washington State Greenhouse Gas Emissions Inventory: 1990-2019
- Washington State Greenhouse Gas Emissions Inventory: 1990–2018
- Washington State Greenhouse Gas Emissions Inventory: 1990–2015
- Washington State Greenhouse Gas Emissions Inventory: 2012–2013
- Washington State Greenhouse Gas Emissions Inventory: 2010–2011
- Washington State Greenhouse Gas Emissions Inventory: 2009–2010
- Washington State Greenhouse Gas Emissions Inventory: 2007–2008
- Washington State Greenhouse Gas Emissions Inventory: 1990 baseline
Like most states that compile statewide emission inventories, we rely primarily on data from the Environmental Protection Agency's (EPA) State Inventory Tool to build this report, which lags by several years.
We're working to provide more frequent emissions updates and decrease the lag time between emissions data and inventory publication by building a team that identifies and collects in-state data to replace and supplement what we currently receive from the EPA.
Greenhouse gas emissions for 2022
Washington's latest greenhouse gas inventory shows the state’s total emissions declined 0.5% from 2021 to 2022, falling from 96.6 to 96.1 million metric tons. That 0.5% reduction equates to half a million metric tons of carbon pollution — about the same as a year’s worth of emissions from 109,000 passenger cars.
The reduction appears to be driven by declines in coal- and natural gas-based power generation, higher wind and solar production, and more hydropower generation – a category that can vary significantly from year-to-year.
In a separate dataset, Ecology also collects greenhouse gas emissions data directly from all the state’s largest emitters. This new dataset, which accounts for most of Washington’s emissions, indicates that statewide emissions continued declining through 2024.
Sources of Washington greenhouse gases in 2022
Speeding up emissions tracking
Since there is no way to track greenhouse gas emissions in real time, Ecology calculates Washington’s emissions after they occur. We’re working to get more current greenhouse gas data to lawmakers and the public.
Our most recent greenhouse gas data is the data we collect annually from the state’s largest emitters. This relatively new dataset accounts for the majority of Washington’s emissions, making it a valuable leading indicator of the statewide total.
Washington’s greenhouse gas inventory relies on many different datasets—most of which are federal-- that become available on different schedules. Ecology recently started publishing the greenhouse gas inventory each year, instead of every two years, and we’re figuring out how to utilize more current state-sourced data.
More frequent reporting and new data sources will decrease the inventory’s lag time.