The latest Dunedin city community carbon footprint showed the city’s total gross emissions dropped 9% over the past four years.
When carbon absorbed by the city’s forests was included, emissions were down 21%.
Mayor Jules Radich said the results were a "good first step towards Dunedin’s zero carbon goal".
The findings were presented to council yesterday as part of the zero carbon work programme.
Cr Lee Vandervis said Covid lockdowns could have affected the result and the drop in emissions might not be down to the council’s efforts.
"We’re kidding ourselves if any of the reductions in emissions are a result of [our] work," he said.
The report said diesel, marine freight and petrol transport made up the three top sources of Dunedin’s emissions after livestock emissions.
During the height of the pandemic, there were significant short-term drops in petrol and diesel consumption.
Council principal policy analyst Jinty MacTavish said some of the changes were attributable to Covid, but preliminary analysis suggested Dunedin people could be making different transport choices.
Cr Vandervis said the idea of Dunedin becoming a world leader in decarbonisation was "fanciful at best".
Cr Steve Walker disagreed.
"We can aspire to be a world leader in emissions reduction, otherwise we might as well pack up, go home and accept an ever-increasing wave of climate disasters," he said.
However, Cr Jim O’Malley and Cr Walker agreed with Cr Vandervis’ comment that lockdowns could have affected transport emissions results.
Cr Walker asked staff to provide the results of travel surveys taken by some of Dunedin’s largest employers, such as the University of Otago, about how their staff travelled to work.
The results of the survey could indicate whether temporary lockdowns affected transport emissions, or if there was a larger "travel mode shift" to more sustainable methods.
An updated report on the zero carbon 2030 goal is due in June.
