Seattle's Green New Deal in 2019 established the goals of net zero emissions by  2030. This includes all emissions from the city, including from individuals, businesses, and industry. Previous to that the city in 2018 had the goal of these reductions by 2030, and carbon neutral by 2050. These goals are what the executive branch is working towards:

Seattle releases a Greenhouse Gas Inventory every two years. The most recent one reports on emissions in 2018. It shows our overall emissions increasing slightly from 2016, with the emissions from Buildings going up by 8.1%, while emissions from Transportation are estimated to be down by 2.4%. However, the reduced transportation numbers, which are based on improvements in vehicle efficiency, do not reflect the increased use of Transportation Network Companies (TNCs) such as Uber and Lyft. Given that our emissions need to decrease sharply in order to meet the goals, this is a huge problem.

Overall, most of our core emissions are from transportation and buildings, with transportation accounting for almost two thirds, and buildings for more than one third, as shown below. 

The bulk of the core transportation emissions come from gasoline, but if you look at the expanded emissions, including the airport, you'll see that jet fuel accounts for a whopping 39%. In fact, emissions from air traffic increased by 40% since 2008.

Core transportation emissions
Expanded transportation emissions

Emissions from buildings are split roughly half and half between commercial buildings (which includes multi-family housing) and residential (small multi-family and single family housing). Within that, the bulk of the emissions are from fossil gas, as shown below:

Residential buildings
Commercial buildings

One area that is not counted in the inventory is emissions consumption: things we buy from other places. Cities such as ours tend to import more emissions than we export, so this is most likely a large blind spot in the accounting.