Wednesday, May 25, 2022

Climate Change: Cut methane now

When the government passed the Zero Carbon Act in 2019, it established a "split gas" target, with separate budgets for carbon dioxide and methane. The logic here was that farmers were a powerful lobby group the government didn't want to annoy methane was a short-lived gas, so we should focus our efforts on the long-term problem of carbon dioxide. But now we're out of time, and scientists are pointing out the obvious: we need to limit heating urgently, so we need to cut methane now:

Cutting methane sharply now is crucial, as focusing on carbon dioxide alone will not be enough to keep rising temperatures within livable limits, scientists have warned.


Cutting CO2 is still essential for the long term, but must be accompanied by strategies to reduce the levels of SLCPs. If not, then temperatures are likely to exceed 2C above pre-industrial levels, the upper limit set in the 2015 Paris climate agreement, even if there are stiff cuts to CO2 emissions.

Dreyfus said sharp cuts to methane and other SLCPs [short-lived climate pollutants] could result in temperatures lower by 0.26C by 2050, which is almost four times greater than the benefit of pursuing CO2 cuts alone, which the scientists estimated would result in temperature cuts of 0.07C by 2050.

She said: “These non-CO2 targeted measures when combined with decarbonisation can provide net cooling by 2030, reduce the rate of warming from 2030 to 2050 by about 50%, roughly half of which comes from methane, significantly larger than decarbonisation alone over this timeframe.”

New Zealand is the 6th worst methane polluter per capita (or maybe the 5th, as Grenada's emissions in that table don't seem remotely close to its past inventory). The rest are all natural gas producers. We're punching well above our weight on destroying the global climate. Which means we have a greater obligation to fix it.

How can we fix it? Take a look at the emissions tracker: we emitted 34.272 million tons CO2-e worth of methane in 2019, and 20 million tons of that was from cows. Capping cow numbers and halving the herd would cut our methane by a third, our gross emissions by a seventh, and our net emissions by a quarter. And we can do it within the normal farm business cycle, in 3-5 years, just by not replacing animals when they go to the works.

Farmers are still clinging to business as usual, trying to pretend they can avoid the emissions cuts the rest of us have to make, still pushing research so they can keep on polluting. But that's just delay and denial. We are out of time, and they need to do their bit. Deep cuts to agricultural emissions are required. No climate policy without them can be considered credible. And any government which refuses to make them should be de-elected and replaced with one which will.