STUDY: Animal Agriculture Is Responsible For More GHG Emissions Than Previously Thought
When using ground-level measurements to predict greenhouse gas concentrations in the air (carbon dioxide and methane), the results are actually 39-90% higher than bottom-up models predict.
SARAH HANNAKEN: ‘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…
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’. SOURCE…
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