Sonoma County had the second smallest household greenhouse gas footprint of the nine Bay Area counties, and 11 local cities and towns accounted for carbon-related emissions below the statewide average, according to a new UC Berkeley report.
The average Sonoma County household had a footprint of 40.4 metric tons of greenhouse gas emissions per year, well below the statewide average of 45.7 tons per household and the Bay Area average of 44.3 tons, the report said.
Only San Francisco, the region’s most compact city with multiple mass transit systems, had a smaller footprint at 38.7 tons of greenhouse gas emissions, while affluent Santa Clara County was tops at 48.6 tons and wealthy communities like Atherton, Piedmont and Alamo accounted for 70 to 85 tons, as income, vehicle ownership and home size contributed heavily to the regional differences.
The average U.S. household accounts for about 50 metric tons of emissions.
Read the UC Berkeley report here
See an interactive map of carbon footprints around the Bay Area here
People with larger incomes “just consume more,” said Christopher Jones, program director of UC Berkeley’s CoolClimate Network and report co-author. They own larger homes which are “full of more stuff,” he said, and also travel by air more often, boosting their expenditures for transportation, which accounted for one-third of Bay Area emissions, the largest source by far.
Food is the second largest source of emissions at 19 percent, followed by goods and services (each 18 percent), heating fuels (5 percent), home construction (3 percent), electricity (2 percent) and waste (1 percent).
Rohnert Park households had the smallest footprint of the eight Sonoma County cities and three communities cited in the report at 37.7 metric tons of emissions per year, while Windsor was highest at 45.1 tons, exceeding the Bay Area average but still below the state mark.
Santa Rosa and Glen Ellen were in the middle of the pack, each at 39.5 metric tons.
Sonoma County households collectively accounted for 7.2 million metric tons of greenhouse gas emissions per year. Californians accounted for 585.5 million tons; households nationwide accounted for 5.8 billion tons of greenhouse gas emissions annually, the Berkeley report said.
Sonoma County is a “good example of low-carbon development,” Jones said, noting the absence of widespread urban sprawl along with relatively modest household income and the benefit of a cool climate that reduces home energy consumption.
The greenhouse gas inventory, produced by the CoolClimate Network and the Bay Area Air Quality Management District, calculated carbon footprints based on household consumption, no matter where the emissions occurred. If a household in Santa Rosa purchased a computer made in China, all emissions from the computer’s production were allocated to the household’s Santa Rosa neighborhood.
In what the report termed a “full life-cycle analysis” of emissions from products and services, motor vehicle emissions included the greenhouse gases from the manufacture of all the vehicle’s parts, assembly and transportation to dealer, as well as vehicle maintenance and refining and burning of the fuel that powered it during its useful life.
The consumption-based approach found about 35 percent higher greenhouse gas emissions than the traditional territorial approach, largely due to “higher emissions from imported food and goods,” the report said.