Animal Agriculture Is Responsible For More GHG Emissions Than Previously Thought
Perhaps you’ve heard the argument: “Industrial animal agriculture is better for the climate than raising animals outdoors in pastures.” If this were true, climate activists and animal protectionists would indeed be at odds. Thankfully, a new paper suggests the supposed advantages of intensive animal agriculture over pasture-based systems are even more minimal than previously thought. The author recommends reducing the overall production of meat and dairy as the most reliable strategy for curbing climate change.
Raising animals for food is a carbon-intensive activity, no matter how it is done. Animal agriculture is responsible for emitting all three of the most common greenhouse gases: carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Animals themselves directly emit methane through their burps and manure, and the energy required to power the farms and produce their feed releases massive amounts of greenhouse gases as well. These emissions are inherent in all formats of animal agriculture, so simply choosing one method of production over another isn’t going to make a meaningful difference.
Indeed, the idea that intensive animal agriculture could be more climate-friendly than pasture-based systems might strike some people as odd. How could anyone think raising animals in highly concentrated, artificial conditions is environmentally superior to the natural, pasture-based methods of our ancestors? The idea comes from the results of a popular method for estimating greenhouse gas emissions, commonly referred to as the “bottom-up model.”
In scientific research, a “model” refers to a complex set of equations scientists use to estimate or predict an outcome that would be difficult to test in the real world. The “bottom-up model” estimates animal greenhouse gas emissions using a wide variety of extremely specific data collected at ground level, such as the number of farmed animals in a given region, the amount and type of feed they eat, their breeding rate, their daily exercise, rate of weight gain and lifespan, the producer’s method of manure storage and disposal, and information about the local climate, along with many additional types of very specific data.
But such information is sometimes difficult to collect and measure accurately. What’s more, due to the nature of the calculations used in this emissions model, even the smallest mistakes in the data can lead to wildly inaccurate results. The author suggests this type of error is precisely what has caused the frequent underestimation of greenhouse gas emissions from industrial animal agriculture operations.
Specifically, the bottom-up model appears to underpredict emissions from manure on factory farms. When methane is measured in the air directly above manure tanks, pits, and piles on farms (as opposed to in a laboratory setting), emissions tend to be far greater than mathematical models predict, sometimes by more than 300%. Taking measurements directly from the air is an alternative way to estimate emissions. Compared to bottom-up models, which use ground-level measurements to predict greenhouse gas concentrations in the air, making calculations based on actual atmospheric measurements is referred to as the “top-down model.” Top-down estimates indicate that total U.S. animal methane emissions are actually 39-90% higher than bottom-up models predict.
Now that we know animal agriculture operations in the U.S. have been enjoying inaccurately low estimates of their greenhouse gas emissions, it is time to set the record straight. The author of this paper urges advocates to counter the still-prevalent claim that intensive industrial agriculture is a superior form of meat and dairy production for the climate. Policymakers mustn’t rely on this misconception when considering climate solutions.
What’s more, even if intensive animal agriculture were more environmentally efficient per unit of meat or dairy produced, transitioning from pasture-based systems to intensive industrial systems would likely still accelerate global warming. This is because intensification of production tends to improve profitability and drive down prices, which leads to more meat and dairy consumed, and thus more production, deforestation, and emissions.
In sum, the misguided call for intensification of animal agriculture is unlikely to achieve the level of emissions reductions predicted by the flawed bottom-up model. Yet, this doesn’t mean grazing animals on pasture is better. To make a meaningful dent in greenhouse gas emissions, climate activists should prioritize meat and dairy reduction (and elimination) and put pressure on governments to adopt (and adhere to) methane reduction targets.
The paper concludes with a practical political reminder: As the push for reducing meat and dairy production gets underway, current producers of these products should be included in the planning and decision-making, and should be supported in their transition to regionally appropriate, sustainable, non-animal agricultural products. Policymakers have numerous tools at their disposal to achieve this shift. Animal advocates should stay on top of progress in this area and do their best to keep pressure on.