Tuesday, April 23, 2024

Tackling methane myths across the spectrum

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Physics professor unpacks the latest thinking about agri and other emissions.
Prof David Frame, Climate Change Research dept, Victoria University.
Reading Time: 3 minutes

A leading climate scientist has given the government’s plan to price farm emissions a tentative tick, but says New Zealand needs to have a conversation about its priorities as the push to reduce emissions intensifies.

Canterbury University Professor of Physics David Frame told the Farmers Weekly In Focus podcast that NZ’s climate strategy relies heavily on reducing emissions from agriculture but asks less of emitters of carbon dioxide.

“We actually have a target that would imply that we are no longer warming the world by about 2035,” Frame said.

“And in fact, we’re undoing some of the warming we’ve created by 2050 and the burden for that reduction in the warming we’ve created falls on rural shoulders. 

“The conversation I don’t think we’ve had is about why it’s okay for urban New Zealand to add more warming over the next 30 years, but rural New Zealand has to reduce it significantly over that 30 years.”

Frame said NZ’s two-gas approach that separates short-lived gases like methane and nitrous oxide from carbon dioxide, a long-lived gas, is the right one.

“I think the commitment to set the price at the lowest level possible to meet the reduction goals is obviously the right one. 

“Why would you want more? Why would you impose a bigger tax than you need?”

But Frame still has concerns about sequestration. 

He supports an idea put forward by Parliamentary Commissioner for the Environment Simon Upton, which proposes allowing methane emissions to be offset by planting trees, but not carbon dioxide emissions.

“I’d like to see that get developed for sheep and beef, especially, to give them extra options.”

Methane’s impact has been debated hotly in rural communities in recent months and Frame said much of what has been promoted doesn’t stand up to scientific scrutiny.

“It’s a sceptic myth that CO2 and methane contributions are overstated,” he said. 

“One of the things that has been a bit disappointing is that some people in rural communities have embraced people like Tom Sheahen, who doesn’t have a record in climate change research and is publicising research by a couple of physicists from the United States, who also don’t really have a record of doing a lot of climate change research.”

They have claimed the climate research community has handled the overlap between different absorption lines in the light spectrum badly.

“But this isn’t really true. That stuff’s been factored into climate models for ages.

“They haven’t really done the background reading to know exactly what everyone does.”

Frame said if they did, they’d realise that most of the effects they’ve assumed are not accounted for, are in fact factored in. 

“We also do know about clouds and the difference between cloudy sky radiation, clear sky radiation and all these things. 

“So the more these guys who come in with the strong claims learn about the field, the more they usually converge with where we actually are.

“It’s a shame that it’s been hyped up as showing that methane is an irrelevant greenhouse gas. That’s just not true. We have a good handle on methane.”

In Focus this week: Taking stock of NZ’s emissions goals

In episode 5 of the In Focus podcast, Canterbury University Professor of Physics David Frame has given the government’s plan to price farm emissions a tentative tick, but says New Zealand needs to have a conversation about its priorities as the push to reduce emissions intensifies.  He also says the sector needs to find peace with the fact that the science around methane is well understood.

Also in this episode, senior reporter Neal Wallace covers the drop in farmgate returns and looks at the global factors causing it.

And Bryan talks to Federated Farmers president Wayne Langford, who thinks the government’s emissions plan announcement was “tone deaf”.

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