Tuesday, March 5, 2024

Papers add to biogenic methane debate 

Neal Wallace
Ag Symposium told that farmers should be hailed as carbon heroes.
Reading Time: 2 minutes

Farmers should be considered carbon heroes, said West Otago organics farmer Alan Richardson.

He was responding to papers delivered at a University of Otago Agriculture Symposium, which included a claim that biogenic methane emissions can be naturally controlled in conjunction with grazing and pasture management.

About 120 people at the symposium were also told that deep-rooting plants will sequester carbon both above and beyond ground.

Research by a University of Otago honours student, Willow Trolove, found diverse deep-rooted pasture species such as red clover, chicory and cocksfoot will sequester carbon at depths of 100mm to 400mm.

University of Otago Emeritus Professor Frank Griffin said a natural chemical process created from the grazing of lush, long pasture effectively neutralises biogenic methane.

His research adds a new element to the discussion on biogenic methane emissions, with science and research focused on animal rumen to reduce the production of methane.

Griffin said global methane levels in the atmosphere have been disproportionately attributed to animals when emissions from fracking and petroleum leakages are significant and increasing.

“It’s not from animals, it’s not from wetlands, it’s most likely associated with rogue gas emissions coming from the petroleum industry.”

The Guardian reported that during 2022 Turkmenistan’s two main oil fields leaked 4.4 million tonnes of methane, more than the United Kingdom’s total annual emissions.

Griffin said nature can control biogenic methane but most research is being done using respirators on animals to measure emissions rather than looking at the natural process.

“We have got to do better if we are going to levy methane. It has got to be for the right reasons,” he said.

When an animal emits methane, the presence of hydroxyl radicals in the atmosphere act as a cleansing agent, consuming most emitted methane.

The presence of very short-lived volatile organic compounds (VOCs) emitted from moist, long, lush-growing vegetation sequesters the rest yet Griffin said this process is being largely ignored by researchers.

VOCs are either absent or not as prevalent in short pasture or areas with little or no vegetation growth such as feedlots.

“Animals living in a nice habitat with a good pasture diet are methane neutral.”

Methane is a significant greenhouse gas and farmers should take it seriously, he said, but there is a natural process that can assist farmers.

Those attending the symposium questioned why this research has not had more exposure given the proposed regulations and funding being invested in mitigation technology.

Griffin said the voice of farmers is important and to advance his research he needs groups to lobby and educate politicians and officials 

Griffin, now retired, previously worked in the Department of Microbiology and Immunology at the University of Otago.

For 35 years he researched mycobacterial diseases, specifically tuberculosis and Johnes, in ruminants and wildlife species, which led to the development of improved diagnostics and molecular techniques for their detection.

He retired in 2016 and is currently a director of Ag@Otago, a programme aimed at using research to enhance the primary sector.

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