Otago contributed 6.9 per cent of New Zealand's emissions in one year despite being only 5 per cent of the population, a new report has found.
The agricultural industry was estimated to be the leading contributor to those emissions by a significant amount.
An inventory on Otago's greenhouse gas emissions between July 2018 and June 2019 was presented to Otago regional councillors during a data and information committee meeting on Wednesday.
The desktop study by consultants Ernst Young used a global protocol for accounting and reporting greenhouse gas emissions, incorporating data held by Otago's five city and district councils - Dunedin, Queenstown-Lakes, Clutha, Central Otago and Waitaki.
It showed that the total gross emissions for the region in 2018-19 was 5,821,025 tonnes of carbon dioxide equivalent (tCO2e).
Total sequestration - or removal of carbon dioxide from the atmosphere - from land use, land change and forestry was 2,640,398 tCO2e.
That offset about 47 per cent of the region's gross emissions, resulting in a total net emissions for Otago of 3,180,627 tCO2e.
The report said that Otago made up 6.9 per cent of New Zealand's 2019 gross emissions and 5.6 per cent of the country's net emissions, while it made up just 5 per cent of New Zealand's population.
Otago Regional Council strategy manager Dr Anne Duncan said the inventory allowed the council to see where the biggest emitters in each district were.
It estimated that the agriculture industry, particularly sheep and beef activities, accounted for 65 per cent of emissions in Otago across four of the five districts.
Transport was the biggest emissions source in the Queenstown-Lakes district and a significant source in Dunedin. It accounted for 16 per cent of the region's emissions.
Electricity usage made up a significant proportion of stationary energy emissions, which accounted for 12 per cent of emissions across the region.
Duncan said the inventory was an important first step towards reducing emissions in Otago.
"It will help us understand our footprint, mitigation options and scenarios, and it will inform discussions and engagement with our communities."
During yesterday's meeting, committee chairwoman Cr Alexa Forbes said the report was "fascinating", but also worrying.
Meanwhile, some councillors felt a national rule regarding which trees are counted towards carbon sequestering was unfair and too strict.
Only trees that reach a height of 5m or more when mature are eligible to be used to offset emissions.
Subsequently, Cr Laws moved a motion that "the report be referred to the council's strategy and planning committee for it to review the 5m tree rule and other methods of capturing carbon sequestering of tussocks, soil and other horticultural activity", which was carried.
The committee also agreed to refer the report to the Otago Mayoral Forum.
The council has proposed undertaking an inventory of Otago's greenhouse gas emissions every two years.