Opinion: Agriculture is an easy target for activists who may not be considering the big picture when it comes to methane reductions, Dr Jacqueline Rowarth writes.
The methane muddle continues, assisted by statements from passionate people presenting their perspective … whether it is or isn't backed up by science.
Thelatest methane report from the United Nations (UN) and the reaction in New Zealand is an example.
While it was presented by activists as an immediate reason to reduce animal numbers in New Zealand, the UN report was clear that "the fossil fuel sector has the greatest potential for targeted mitigation by 2030".
Methane from fossil fuel is not as big as from agriculture, but it is increasing.
Stanford University researchers have calculated that between 2000 and 2017, methane emissions from fossil fuel increased 15 per cent, reaching 108 million tons (Mt). Methane emissions from agriculture increased 11 per cent, reaching 227 Mt.
Global agricultural emissions are over twice those from fossil fuel, hence animal methane is the target for many activists. But the UN report has suggested that mitigation measures already exist for the fossil fuel industry, and that they are readily available. The same cannot be said for agriculture.
Fossil fuel extraction is associated with what are termed fugitive emissions – leaks.
Methane bubbles up from underground, and escapes into the atmosphere from oil jacks and rigs, natural gas wells and coal mines.
Leaks aren't always identified but fixing them increases the amount of fuel available to be sold to customers.
Fixing them also reduces any taxes associated with emissions (but only if taxes are in place).
The UN calculates that emissions could be reduced from the oil and gas sector by 29–57 Mt/yr and from the coal sector by 12–25 Mt/yr.
Furthermore, up to 80 per cent of oil and gas measures and up to 98 per cent of coal measures could be implemented at negative or low cost.
Action would seem to be a "no-brainer" but requires that the industry actually takes steps. The big oil producing countries have only recently accepted the need for commitment to reduction goals.
Methane from waste, which accounts for about 20 per cent (64-71 Mt/yr) of methane emissions globally, can also be addressed. The UN calculates that implementing existing measures for mitigation could reduce methane emissions from landfill by 29-36 Mt/yr.
That leaves agriculture.
Rice cultivation contributes approximately 8 per cent (24-40 Mt/yr) of global anthropogenic emissions and animal emissions from manure and enteric fermentation (in the rumen) represent roughly 32 per cent (110-121 Mt/yr).
Dr Jacqueline Rowarth. Photo / Supplied
Existing targeted measures could reduce methane emissions from rice cultivation by 6–9 Mt/yr. For animals the targeted mitigation potentials are less consistent, ranging from 4–42 Mt/yr, very much depending upon the efficiency of the system being considered.
The UN report recommended improved livestock management, which included feed quality and animal health, as being key to reducing methane per unit of production.
New Zealand, which produces approximately 0.37 per cent (Ministry for the Environment estimate; approximately 1.34 Mt/yr) of global methane, is already extremely efficient in conversion of non-human edible food to high quality protein and is constantly trying to do better.
The New Zealand Agricultural Research Centre leads the global research on methane in livestock (leadership is a mark of recognition by the global community) and is at the forefront of evaluating mitigation techniques.
This position of leadership doesn't let agriculture "off the hook" but does make it difficult to do better.
In contrast, methane leakage has been acknowledged by Energy Resources Aotearoa (the industry body representing oil and gas) and is now a priority for the fossil fuel industry.
Food waste, which leads to methane from landfill, continues to be a problem and New Zealand ranks amongst the highest creators.
Of note is that some innovative farmers are using waste from food processors as cattle feed, thereby turning human inedible material into high quality protein and saving methane from landfill… but are creating methane from the rumen instead.
Listen to Jamie Mackay interview Dr Jacqueline Rowarth on The Country below:
The biggest component of food waste is bread, fruit and vegetables – exactly the foods that activists state we should grow instead of having ruminant animals. But carbohydrates and vitamins aren't the same as high quality protein.
And though Greenpeace has suggested that government should support farmers to move from dairying to producing a diverse range of products … the issues of markets, infrastructure, costs of production and economies of scale indicate that New Zealand would need a far greater human population than currently exists to support the idyll.
The point about our current export economy is that New Zealand is cost competitive and greenhouse gas efficient in pasture-based protein.
The UN methane report stated that there is limited potential to address methane emission from agriculture with technological measures.
It recommended three behavioural changes: reducing food waste and loss, improving livestock management, and the adoption of healthy diets (vegetarian or with a lower meat and dairy content). Adopting these measures could reduce methane emissions by 65–80 Mt/yr over the next few decades globally.
New Zealand's role in agriculture is doing the research which will help the world in reducing ruminant methane and is already the example in least impact for most protein.
We can also encourage everybody to think before they purchase, whether fuel or food, what waste will be created.
Dr Jacqueline Rowarth is an adjunct professor with Lincoln University and a farmer-elected director on the Boards of DairyNZ and Ravensdown. The analysis and conclusions above are her own. jsrowarth@gmail.com
