Even if all livestock floated off into space this afternoon, dangerous climate change would continue unabated
- Susan Harris
- Jun 4
- 8 min read
Why? Because emissions from fossil fuels continue to increase at pace, overwhelming any difference that taking livestock off the planet would make
Consequently, methane reduction targets for agriculture are misguided and pointless. They are a distraction from the real problem: increasing fossil-fuel-sourced emissions. Reducing livestock emissions will make no difference at all to the pace of climate change and will place unnecessary pressure on farmers to reduce livestock numbers; thereby reducing their income and the production of food. The "Flying Cows" theory of methane reduction.
The recent Open Letter to the New Zealand Prime Minister from 26 leading climate scientists posits the Flying Cows theory to criticise New Zealand and Ireland's new methane targets. There are some basic errors of context, science, reality, and practicality in this letter.
Global Warming Potential of different gases
The global warming potential (GWP-100) of different gases is calculated by using a proxy "carbon dioxide equivalent". It represents how much heat a greenhouse gas traps in the atmosphere over 100 years. Carbon dioxide has a GWP of one, and methane a GWP of 27 since it has 27 times more warming potential than carbon dioxide. The GWP of emissions are expressed by combining the GWP of the different gases into carbon dioxide equivalents. GWP expression needs to be managed carefully however, since methane breaks down after about 12 years in the atmosphere; whilst carbon dioxide hangs about for 300-1,000 years, around 75% of it for 1,800 years, and some proportions for over 5,000 years. This means the effects of global warming from carbon dioxide emissions can persist for millennia, so it is critical to get the math right and include types and amounts of gases (tonnes) and their atmospheric lifetimes when forecasting GWP. Remember by definition, GWP represents only 100 years' warming of 25% of carbon dioxide emissions (very conservatively), so it probably under-represents carbon dioxide-forced warming over longer periods.
Total Climate Model
The impact of greenhouse gas emissions on the planet need to be placed in a global context looking at all gas sources at once - a "Total Climate Model" - since the atmosphere responds only to the quantity of gases present. It doesn't care where they came from.
New Zealand and Ireland together emit about 0.3% of all global emissions. Even if both countries shut down completely and reduced their emissions to zero, that would make absolutely no difference to the increasing pace of global warming.
Total global emissions in 2024 were projected to rise 2.5% (actuals not yet available), with 90% of this increase from fossil fuel emissions (WMO 2024). This is eight times more increase in one year than New Zealand and Ireland's total emissions put together.
Importance of a country's greenhouse gas profile
A country's GHG Profile determines how practical and effective it is to reduce emissions by various means. New Zealand and Ireland have a unique GHG Profile because of their small populations, agricultural industry, and the sources of their energy production. In 2023, 80% of New Zealand's energy production was from renewable sources, whilst Ireland's was 59%. Some 53% of New Zealand's emissions were from agriculture (mostly livestock methane), whilst Ireland's were 38%. These profiles are unusual, as most developed countries' GHG Profiles are dominated by fossil-fuel driven energy emissions. For example, Australia's and the United States' energy emissions dominate their profile.
Both New Zealand and Ireland have decarbonised their energy production significantly. Ironically this has created a "false negative" for both countries in climate statistics and makes livestock emissions assume more importance then they should. Livestock were around long before fossil fuels were discovered, and it is the huge increase in fossil fuels burned that has created dangerous climate change, not the comparatively very minor increase in domesticated livestock numbers and their natural emissions over the past 135 years.
The diagrams above illustrate how pointless it is to focus any attention on reducing methane emissions in the agricultural sector. Even if all agriculture was abandoned worldwide, global warming would still continue because historical and increasing fossil-fuel-sourced energy production is the real problem.
The fallacy of setting agricultural methane targets when industrial methane emissions undermeasured and fossil fuel industry expansion continues at pace
The most recent research into methane missions from fossil fuel sources shows that methane emissions are under-reported by about 80%. For example, just one leak (the worst on record) from an accident and fire at Kazakhstan’s Karaturun East oil field over 205 days in 2023 emitted 134,000 ± 34,000 tonnes of methane (Guanter et al 2024). This one event was equivalent to about 6% of annual livestock emissions in New Zealand and Ireland.
Under-reporting of methane emissions from operating plant, leaks, and accidents take global fossil-fuel-sourced methane emissions out to almost twice agricultural emissions (IEA 2025).
At the same time, fossil-fuel industry expansion is continuing at pace. Just last week the Western Australian Government approved the contentious North-West LNG field development, which is projected to emit 6 billion tonnes from 2040 to 2070, increasing Australia's energy emissions 70% per year over 30 years on its own. This is equivalent to 105 years of livestock emissions from New Zealand and Ireland together.
Expansion of the oil and gas industry continues at an immense rate worldwide - 96% of oil and gas companies are exploring and developing new reserves across 129 countries (Urgewald). The 230 billion barrels of untapped oil and gas are projected to release the equivalent of 1,790 years' worth of emissions from New Zealand and Irish livestock, or 30 times the current emissions of the EU. If they occur, such developments will put humanity on the path to a terrifying increase of 5°C+ in global temperature. The disastrous future impacts of this increase will make the wars in Gaza and Ukraine look like schoolyard skirmishes.
Committing climate seppuku
The Open Letter chastises New Zealand and Ireland for weakening their methane reduction climate targets. The brief analysis presented here shows that agricultural methane targets should be abandoned entirely because they are pointless. The Open Letter encourages New Zealand and Ireland to commit climate seppuku for no good reason and misrepresents reality.
Methane reduction is not like pouring 90 rather than 100 barrels of "pollution" into a river and getting a credit for the ten less. In this inaccurate allegory, livestock methane is not a pollutant because the river (environment) can process the relatively small natural quantities of it. The professor has neglected to mention that the energy industry operator upstream has already polluted the river with 700 barrels (emissions by sector), far beyond its ability to cope. Similarly, as noted above, any reduction in agricultural methane from New Zealand or Ireland will have absolutely no effect in limiting warming to 1.5°C. That limit has already passed. Need to go talk to the fellow tossing 700+ barrels into the river and stop him.
One argument supporting the Paris Climate Agreement was that everyone "should do their bit". An admirable principle if applied correctly. But what if doing your bit makes no difference at all to the climate and impoverishes your country while the larger climate villains don't do their bit? Other small Island Nations are also in this position but worse, since the unequal tragedies of climate change are due to drown their living spaces first.
Major emitters lobby politicians to the point of suffocation and spend fortunes many times more than the New Zealand and Irish GDP combined to expand their businesses and increase their dividends. Their climate suicide squad actions will accelerate climate change to unimaginable levels of disaster and suffering and ultimately end up destroying their very businesses as well. To date, only the insurance industry is taking the climate threat seriously, as dangerous climate change is already impacting their bottom lines. Some activist company shareholders are aware of the existential climate risk and are lobbying boards to change direction to 21st Century-focused risk assessment (not 19th), clean energy, and serious decarbonisation. The authors who signed the Open Letter would do better to join them and turn their lobbying efforts to persuading energy and emitter majors to transit from dirty energy to clean energy, seeking funding from them to accelerate research efforts into speeding that transition. These are much harder political targets and research challenges than lambasting the small, climate-embattled New Zealand and Irish Governments.
Farmer climate assurance, muscular international lobbying, and diplomatic work required in the meantime
Methane is a mere sidekick to the real climate villain of carbon dioxide produced by fossil fuels. Our pastoral industries and Government need to plan their responses on this basis, and not be deceived into spending money on heroic but ultimately futile methane reduction projects on ruminants with a 10,000 year adaptive history of seriously complicated multi-stomach digestion. The small methane reductions hard won at significant expense by such projects are immediately confounded by current oil and gas leaks and new projects overseas. China, Russia, India and Iran, four of the top five oil and gas producers, have not signed the (non-binding) Global Methane Pledge, and none of the signatories are keeping to their commitments anyway.
A better strategy for New Zealand and Ireland is to focus on eliminating the real villain - carbon dioxide. Apart from decarbonising our energy sources, we have very little influence on replacing fossil-fuel based technologies with clean technology, so transition will be challenging. Nevertheless, we can demand fossil-fuel-free tractors, diggers, excavators, trucks, harvesters, and 4WD utes from the manufacturers, encourage EV uptake, plant as many trees as possible with the right species in the right places, and bank high integrity carbon credits for agriculture to protect our farm operators during the clean energy transition like other industries are doing. Pay the scientists to do research on topics that will make a real difference. Ask them, they will know what these are.
Muscular international lobbying and diplomatic work is required in the meantime to get livestock's natural emissions excluded from the Paris Agreement and demand big nations do their bit. Perhaps Ireland and the other major protein producing nations will help with this.
We must forget any type of local fossil fuel expansion and not join the climate suicide squad. Looking for more oil and gas is putting out the fire with gasoline. Notably, solar energy is now the cheapest source of energy, and solar energy expansion is underway in New Zealand and Ireland. Sun, wind, geysers, freshwaters and ocean provide limitless energy if we are clever enough to catch it.
We must leave a clean energy heritage and a habitable planet for our children. Blaming cows and sheep and buffalo and goats and pigs and horses and mules and chickens for dangerous climate change is ludicrous.
Better go lasso those girls in for milking.
Note: The views expressed in this Think Piece are entirely those of the author.
Susan Harris BSc(Hons), MEIANZ, MNZPI
Mrs | She
Chief Scientist
GreenXperts Limited
New Zealand
ph: +64 22 1544 958
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