A group of independent scientists from across the globe have written an open letter to New Zealand Prime Minister Christopher Luxon expressing concern over plans to introduce a new biogenic methane target based on the goal of “no additional warming” which they say would jeopardise New Zealand’s commitments under the Paris Agreement and the Global Methane Pledge.

Methane has roughly 80 times the heating effect of carbon dioxide over a 20-year period and an atmospheric life of around 12 years compared to hundreds of years for carbon dioxide. Because of these properties, the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment report concludes that swift reductions in methane pollution are a key component of actions to limit warming in line with the long-term temperature goal of the Paris agreement, which aims to avoid potentially catastrophic tipping points.

The letter states that adopting targets consistent with “no additional warming” ignores this scientific evidence and redefines the goal of climate action as simply stabilising the warming impact of emissions from any given source at current levels, rather than seeking to “minimise all greenhouse gas emissions”, and their contribution to global warming.

Signatories include Drew Shindell, professor of climate science at Duke University and chair of the 2021 UNEP Global Methane Assessment (US), Joeri Rogelj, professor of climate science and policy at the Centre for Environmental Policy, Imperial College London (UK), and Dave Reay, professor of carbon management and education, School of Geosciences, University of Edinburgh and co-chair of the Just Transition Commission (UK).

In total over 20 scientists and academics have signed the letter.

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