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The great methane debate explained
21st Sept. 2025
Long-running debate around agricultural methane in emissions targets and pricing forms the basis of new government methane policy, due for release.
1 minute read
There has been a long-running debate around the role of agricultural methane in greenhouse gas targets and emissions pricing. This is at the heart of a new government position on methane targets, due to be released shortly.
At the heart of the debate has been the timeframe that different gases remain in the atmosphere. Methane is far more powerful in heating the atmosphere than carbon dioxide (by a factor of over 80 times over a 20 year period) but it degrades quite quickly. Most emissions break down in the atmosphere over a decade, compared with carbon dioxide that stays in the atmosphere for centuries.
How methane is accounted for in climate policy depends on those timeframes. For the past 30 years, the global climate change negotiations have agreed that the timeframe for rating the atmospheric impact of greenhouse gases should be a century.
However, a few climate scientists and many farmers argue that the timeframe used should be longer and methane should be downrated in terms of its impacts. The government has been persuaded by their lobbyists to review methane targets so that methane emissions would not increase global heating any more than the current level. This would lock in current levels of global warming, with the prospect of continued extreme weather damage.
Most climate scientists either support the 100 year timeframe or argue that the most severe risks that we face are in the short term. If we breach key tipping points, we may face runaway climate change processes that would have even more disastrous consequences than forecast.
So what happens over the next decade is crucial and according to that rationale, methane is under-rated. Many countries, including some of New Zealand’s major trading partners, are calling for far deeper cuts in methane than in current targets.
The stakes for New Zealand’s exports, particularly agricultural products, are high.
The following RNZ explainer provides more detail.
https://www.rnz.co.nz/news/top/572041/the-great-methane-debate-explained