Are cows killing the planet?
“Cows are killing the planet”. This statement is something that is increasingly heard from farmers who believe that this narrative is widely accepted by environmentalists, climate scientists and the wider public. It is not.
In 2023 the Intergovernmental Panel on Climate Change’s (IPCC) sixth assessment report estimated that agriculture, forestry, and other land use contributed 22% of global emissions. The world resource institute in 2022 estimated that 'livestock and manure' account for 6% of global emissions. These numbers can vary depending on different methodologies and inclusion or exclusion of certain elements, most notably direct emissions from agricultural production vs the wider food system. For example, the UN Food and Agriculture Organisation (FAO) estimated in 2019 that our food system (including agriculture) accounted for 31% of global emissions with livestock contributing 15% (including feed, land use change etc).
These figures are significant and highlight agriculture’s contribution to climate change which we, as an industry must work to reduce. However, if we take the 31% figure, this still leaves 69% of emissions with other industries. Therefore, no climate scientist, environmental scientist, or consultant with integrity, would suggest that livestock are the main driver of climate change.
Of course, this does not mean that livestock systems are inconsequential. They do make a significant contribution, a contribution that we must work to reduce, but livestock agriculture alone is not ‘killing the planet’.
The belief in this narrative has created some interesting responses from those within the agricultural industry seeking to tackle this claim, particularly where methane is concerned.
For clarity, there is no conspiracy amongst climate scientists to deceive the wider public into believing the impact of methane on warming is greater than it is. There are methodologies for calculating the warming impact of methane on the planet, and there is relevant scientific debate as to the best way to compare methane to carbon dioxide. The debate centres around methane's lifespan in the atmosphere, methane has a shorter lifespan than carbon dioxide, but methane has a significantly greater warming effect.
The current IPCC and widely accepted approach uses GWP100 (Global Warming Potential), which attempts to spread the warming impact of methane over 100 years while accounting for the short lifespan of the gas. GWP*(GWP star) is a method that claims to do this better than GWP100 but is not yet widely accepted or used. If and when it does become widely accepted, it will become more commonly used.
GWP* assumes that if you do not increase methane emissions, you do not increase warming. This is accepted in the scientific literature and is not something that climate scientists have been suppressing, as some recent on social media posts and videos on the subject have claimed.
It comes down to understanding how greenhouse gases (GHGs) contribute to warming the planet. Simply put, warming occurs when heat from the sun that is ordinarily reflected back out into space gets trapped in our atmosphere by GHGs. If we increase the GHGs, we increase the amount of heat that stays in the earth’s atmosphere, increasing the global temperature. If livestock numbers are stable, with no change in numbers, there is no increase or decrease in the rate of warming but crucially there is still a warming effect. If we stabilise methane emissions today, the warming effect from that methane will still be occurring in 100 years because we are still emitting methane, regardless of the breakdown of methane to carbon dioxide every 12 or so years. Thus, it is imperative to reduce absolute methane emissions to mitigate global warming.
There are many ways we can do this. At the forefront, improved efficiencies across the agricultural sector would bring about positive benefits to climate and, for the most part, productivity and profitability of the industry.
Each farm business will have a different pathway to reducing methane emissions but there will always be something that can be improved. In the future, genetics, feed additives, and other technologies will help us further.
The agricultural industry does not benefit by countering the claims that ‘cows are killing the planet’ with other spurious claims around methane and ultimately climate change denial. There are reasonable cases to be made to challenge this statement without stooping to that level.
As individual farm business and a wider industry, we can choose which path to take. We should accept that climate science is complicated and there are everchanging areas of research in this field, and we should strive to reduce emissions in our agricultural practices where possible. We must also adapt to the changing climate by building resilience in our businesses and show our industry peers that we are forward thinking, innovative, and can respond to the challenges that climate change will bring.
Posted by Séamus Murphy on 24/05/2024
