Greenhouse gas emissions in Seattle crept up about 4.7% after the COVID-19 pandemic.
The city’s core emissions — from the transportation, building and waste sectors — saw an increase of about 132,500 metric tons of greenhouse gases from 2020 to 2022. That increase is equivalent to about 31,000 gas-powered cars on the road for a year, according to calculations from the U.S. Environmental Protection Agency.
More cars on the road, more extreme weather and more recyclables and compostables brought to landfills are thought to have contributed to the rise.
During the same period, Seattle’s population grew about 2% and the economy grew 22%, according to the city. Despite the rise, emissions remained lower than in the years before the pandemic.
Earlier this year, most Eastside cities reported their greenhouse gas emissions also remained below the highs seen before the pandemic.
The state is required to publish an inventory report of its emissions every two years. The latest report showed the state saw its highest level of greenhouse gas emissions in over a decade in 2019 due to an increase in electricity demand and poor hydropower production, forcing utilities to rely on coal and methane for electricity generation.
The state’s next report is slated to be released this month and include emissions through 2021.
In Seattle, emissions from transportation — passenger vehicles and trucks — made up about 46% of the overall increase of emissions from 2020 to 2022. Transportation emissions typically account for the lion’s share of overall emissions, according to data provided by the city, so it is likely that smaller percentage changes within the transportation sector will have a larger corresponding effect on overall emissions.
The city saw about a 9% increase in vehicle miles traveled from 2020 to 2022, but overall transportation emissions increased by about 4%. This coincided with an increase in the number of electric, plug-in hybrid and other more efficient passenger vehicle registrations, as well as an increase in transit ridership, according to the city.
A rise in emissions from buildings contributed to about half of the overall increase. The city saw more extreme weather events, including an increase both in warmer and colder days in 2022 that likely drove the use of fossil fuels to heat or cool homes and businesses. There were 13 to 15% warmer and colder days in 2022, according to the city.
Colder weather has a bigger impact on the city’s emissions due to the burning of fossil gas versus running electric heat, or air conditioning in warmer weather, according to the city.
“We need to get to a point where our buildings infrastructure and our transportation infrastructure is resilient to all of these variables like more extreme weather, travel patterns changing because of the pandemic, or any other reason,” said Ani Krishnan, climate data and policy manager with the city’s office of Sustainability and Environment. “When we focus on electrification, … we will start to insulate ourselves from those changes.”
The city’s emissions inventory includes offsets equivalent to 97,000 metric tons of greenhouse gas in 2022.
Overall, the city’s core emissions have fallen about 12% since 2008, while the population increased by about 26%, according to data provided by the city. The largest reductions were seen in transportation emissions, which accounted for about 73% of the decrease, followed by buildings and waste.
These reductions are partially attributable to changes in policies at the local, state and federal level to improve energy efficiency standards, increase access to transit and incentivize a transition away from fossil fuels.
Since 2008, Seattle has seen light rail expand further north, the city has continued to update its building energy standards and more efficient passenger vehicles have been introduced.
The city reduced building-related emissions 24% and energy 25% across city-owned buildings from 2008 through 2021.
The core emissions don’t include industrial energy use and other industrial emissions, emissions from freight and passenger trains, marine emissions from ferries or other boat traffic or air travel, among other things.
The city can access gas or electricity use data from utilities and say with a high level of certainty the emissions number from the building sector. Similarly, for waste, the city can look at how many tons of waste are hitting the landfill and calculate emissions.
But there are other data sources where it may be harder to tease out the emissions, said Krishnan, climate data and policy manager with the city’s Office of Sustainability and Environment. For example, it could be difficult to definitively say what percentage of jet fuel sales at local airports could be attributed to Seattle residents versus others in the region or passengers traveling through.
These expanded emissions, including less certain data sources, totaled about 5.78 million metric tons of greenhouse gases in 2022, up from about 5.1 million in 2020.
Instead, the city’s calculations focus on core emissions from the transportation, building and waste sectors, where the data is more reliable. The city’s core emissions include sectors where the city has emissions reduction targets that were formally adopted in 2011 and are in its Climate Action Plan released in 2013.
These core emissions totaled about 2.98 million metric tons of greenhouse gases in 2022, compared to about 2.85 million in 2020.
The city anticipates these emissions will continue to ramp down as legislation requires large commercial and residential buildings in Seattle to phase out the use of fossil fuels.
The building emissions performance standard applies to about 4,100 buildings that are 20,000 square feet or larger, or about 3% of all buildings. These buildings, according to the city, produce about one-third of the total emissions from buildings.
Building owners and managers must produce a plan to ditch fossil fuels before 2031 when reductions will be required for some buildings and the city could start to issue fines.
The city anticipates a roughly 35% reduction in emissions through the implementation of this in addition to the clean heat program, which provides incentives to replace oil and gas heat with electric heat pumps.
Material from The Seattle Times archives was used in this reporting.
The opinions expressed in reader comments are those of the author only and do not reflect the opinions of The Seattle Times.
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