A team of concerned farmers and scientists say the climate change modelling used by the Government is flawed, and the proposed agricultural emissions tax it is based on will ‘’devastate New Zealand’’.

They have formed the Methane Science Accord, with the aim of getting political parties to show their hand on their proposed methane tax policies to allow the public to make an informed vote in next month’s election.

North Otago sheep and beef farmer Hamish Carswell, who is one of the instigators of the Accord, said methane as a greenhouse was overstated, and the group wants the Government to stop using the GWP100 metric in its calculations.

“The science in this area is evolving quickly, and the Government needs to adopt the latest information from the Intergovernmental Panel on Climate Change, which admitted that methane’s warming potential had been overstated by 400%,’’ he said.

“We want to get as many signatures as possible, so we can go to the political parties and show that thousands of New Zealanders are concerned about this. They are using outdated measures, which have been discredited by the IPCC.

We are not climate change deniers, we just want the Government to use the most up-to-date information. If they keep going the way they’re going, it’s the death knell for farming and that has massive implications for everyone.’’

The Accord’s campaign letter points out that the Government signed the Paris Accord which says any climate mitigation policies must “not threaten food production”.

”We’ll be putting pressure on the political parties closer to the election – it’s about getting people and businesses to sign up and show their support at the moment so we can influence the politicians,’’ Carswell said.

A public letter lists more than 50 supporters of the Accord, and it is supported by advocacy groups 50 Shades of Green, FARM, Groundswell NZ and the Rural Advocacy Network.

The Government released its He Waka Eke Noa system of farmgate emissions pricing proposals in October 2022 but did not get it through Parliament before the election.

Under that plan, up to 20% of sheep and beef and 5% of dairy would have been lost or farms would have closed completely under Government modelling.

In August, Agriculture Minister Damien O’Connor released a statement saying the Government had worked with farming leaders to design a final plan to reduce agricultural emissions.

“We believe the best approach to rewarding sequestration on-farm is putting scientifically validated forms into the New Zealand Emissions Trading Scheme (NZ ETS), rather than establishing a parallel system,’’ O’Connor said.

“This will provide a pathway for methods such as indigenous vegetation or riparian plantings to be recognised, and research is already happening in this space.’’

The Government shifted farm-level emissions reporting requirements into Quarter 4 of 2024 and emissions pricing won’t start until Quarter 4 of 2025; and work will also get underway to allow scientifically validated forms of on-farm sequestration into the ETS, which can help reduce the cost to farmers, he said.

“Our decisions accommodate the key issues raised by the partners on timelines, and also set a framework for the factors that will determine the farm-level levy price.

“Our plan is one that supports farmers’ transition, helps secure their future export growth, and works alongside our other climate policies to continue reducing our emissions.’’