Working with scientists at Manaaki Whenua and supported by local iwi, in particular Ngāi Takoto and Awarua Runaka, in October 2024 the Department of Conservation published the first detailed study on carbon emissions from these peatland fires.
Peatlands are a type of wetland with an incredible ability to store carbon in peat, built up over tens of thousands of years. However, peat wetland soils are highly flammable when water levels are low, which can occur during extended dry periods and be exacerbated by drainage of surrounding agricultural land. In Kaimaumau the burnt area was over 2,900 hectares, and at Awarua it was 980 hectares. The fires also caused a loss of most of the above-ground vegetation.
Estimated carbon emissions from the 2022 fires were large, with more than 500,000 tonnes of carbon dioxide emissions from Kaimaumau and more than 100,000 tonnes from Awarua. If these losses had to be paid for, the estimated cost would have been about NZ$32-$36 million based on current carbon markets.
Manaaki Whenua Senior Researcher Dr Jack Pronger says the loss of carbon due to the two fires represents about 5% of AoNZ’s annual reduction target for the 2026-2030 period relative to the previous emissions budget – and that this is likely to be a conservative estimate of the total loss.
Researchers at Manaaki Whenua, the Department of Conservation, Waikato Regional Council and the University of Waikato are currently determining whether it is possible to determine carbon losses from the more recent Whangamarino wetland fire that occurred in October 2024.
In other work on peatlands, Manaaki Whenua’s researchers have been working to improve emissions accounting for Organic Soils (funded by the Ministry for Primary Industries) and estimating the potential additional contribution that could be coming from peaty mineral soils (mineral soils that include a peaty layer), as part of the Maximising Carbon in Soils programme funded by the Ministry for the Environment. Preliminary estimates demonstrate these peaty mineral soils may be contributing emissions of 1.0 to 2.4 megatonnes of CO2 equivalents per year to AoNZ’s greenhouse gas emissions, large enough to require reporting to the UN Framework Convention on Climate Change as a significant source of emissions.
We are working on potential mitigation actions to reduce emissions from Organic Soils through multiple collaborations including with the University of Waikato and Waikato Regional Council and Irish partners who face similar issues. Future mitigation research is being planned in collaboration with the NZ Agricultural Greenhouse Gas Research Centre.
