Urban systems are a major source of carbon dioxide emissions from fossil fuel combustion and increasingly a source of methane losses from both landfills and leaky conveyances. Understanding the drivers of urban greenhouse gas emissions is an important step towards addressing solutions to reduce future global warming impacts. Here we highlight long-term observations from the Salt Lake Valley, Utah and surrounding areas. We present trace gas data from both fixed and mobile observatories. We include also an analysis of spatially distributed 14C leaf observations as a season-long proxy for elevated carbon dioxide levels within the urban dome. Lastly, we discuss a framework for modeling and analyzing urban greenhouse emissions that can be used for historical reconstruction, current conditions, and planning purposes.