For years, cities have been taking on efforts to reduce their carbon footprint by reducing greenhouse gas emissions. Yet little has been done to verify if such work has the intended outcome.

New research from the University of Kansas found that completing a greenhouse gas emission inventory indeed moves the needle toward mitigation. “Sustainability” can refer to any number of efforts a municipality can employ, but research has found that when American cities conduct a greenhouse gas emissions inventory, they reduce their CO₂ emissions significantly more than they would have otherwise.

“We found evidence that the construction and development of a GHG (greenhouse gas) emissions inventory was causally linked to fewer fossil fuel carbon dioxide emissions,” said Rachel Krause, professor of public affairs and administration at KU and the study’s lead author. “Inventories reflect considerable investigation into the source and amount of local emissions, and we hypothesize that this information increases ability to manage efforts and allowed for change.”

Completing such an inventory, as well as employing sustainability directors or professionals in city government, are two of the most common methods cities have used to boost sustainability and reduce emissions, and researchers wanted to examine the understudied area of how effective those efforts are.

Researchers gathered data from cities across the United States identifying whether they had an emissions inventory and/or sustainability staff in place in both 2010 and 2015. Because the goal was to determine the difference that these investments generate, only those without them in place in 2010 were included in the analysis.

This yielded a sample of 702 municipalities to examine the emissions inventory and 484 for the sustainability staff. The research team then used satellite-gathered emissions data to calculate emissions released within the cities’ boundaries and compared the differences in emissions from the two points in time for groups of cities that did and did not make these investments.

“The estimation method we used controlled for over time and between city differences and indicates a statistically significant link back to this treatment,” Krause said of the emissions inventory. “Looking at fossil fuel-based CO₂ from on-site residential emissions is a small piece of the overall pie, but the fact that there is evidence of real impact is relevant.”

Researchers examined emissions from on-site residential settings and on-road traffic. The results showed that conducting an emissions inventory results in about 22 fewer pounds of emissions per capita. The reduction appeared primarily via residential emissions.

The addition of sustainability staff, however, did not show a statistically significant reduction.

The study was co-written with Angela Park of the KDI School of Public Policy and Management in South Korea, who is also a public affairs alumna of KU; Christopher Hawkins of the University of Central Florida; and Aote Xin of Claremont Graduate University. It was published in the journal Cities.

Krause reiterated that the findings do not mean that employing sustainability staff is not a worthwhile investment for cities. Sustainability can mean many things and just because the study did not find that the addition of staff results in fewer emissions does not mean they have not influenced important improvements in other areas.

“Because greenhouse gas emissions are influenced by many factors—including climate, macroeconomics and higher-level policy—some people argue that local efforts aren’t large enough to matter,” Krause said. “The causal reduction shown following an emissions inventory is meaningful and adds to an area of research that was lacking.

“It’s not going to solve the issue, but is there evidence that these accounting and planning efforts are moving the needle in the right direction? We are finding that the answer is yes, they are. I posit that means something.”

As national and international political and policy priorities change, cities will continue to be among the most active in addressing greenhouse gas emissions, she added. Data is now beginning to show that investments and action taken by municipalities can move the needle.