Abstract
Environmental impacts of intensive, industrial meat and dairy production are a major concern. However, the majority of global warming emissions from animal agriculture are estimated to come from extensive, pastoral systems of production. Animal emissions are estimated using complex models, but these models can contain multiple errors that often go unreported. Modeled emissions estimates can be corroborated using measurements of greenhouse gases in the air above and downwind of areas where animals are raised, using planes, tall towers, and satellites. These atmospheric measurements suggest that total global animal emissions are accurately estimated by models. However, in the US, where production is predominantly industrialized, animal emissions are frequently underestimated by models.
Generated Summary
This document is a guidance memo focusing on the underestimation of U.S. greenhouse gas (GHG) emissions and the global implications of industrializing animal agriculture. It explores the use of emission models, particularly the discrepancies between bottom-up and top-down estimates, and their impact on understanding the environmental effects of meat and dairy production. The memo examines how intensive animal agriculture is justified, the role of intensification in sustainable development, and the limitations of current emission models. It also delves into the environmental tradeoffs of intensive animal production, the role of animal production in economic development and climate change, and the potential for methane mitigation strategies. The methodology involves a review of existing literature, analysis of emission models, and comparison of different production systems to assess their environmental impacts and climate change implications. The scope includes a focus on the United States, while also considering global contexts, especially in low- and middle-income countries where demand for these products is rising.
Key Findings & Statistics
- Global meat consumption is expected to increase by nearly two-thirds in the coming decades (Alexandratos and Bruinsma, 2012).
- Animal agriculture accounts for 14.5% of global greenhouse gas (GHG) emissions (Gerber et al., 2013).
- Beef is responsible for the highest number of emissions among major animal food categories.
- In the US, animal emissions are frequently underestimated by models, especially when production is predominantly industrialized.
- Emissions from animal agriculture consist of direct (enteric fermentation, manure management) and indirect (feed production, farm energy use) emissions.
- High-efficiency, intensive production systems in North America and the EU are estimated to be responsible for fewer global emissions per unit of meat or dairy.
- Top-down atmospheric estimates indicate that total US animal methane emissions are 39-90% higher than bottom-up models predict.
- The difference between top-down and bottom-up estimates is much greater in the United States compared to the global average.
- In the US, California airborne measurements revealed that dairy cattle and non-dairy animals’ emissions were 45% and 69% higher, respectively, than the bottom-up model predicted.
- Hypothetically shifting the US back towards exclusively grass-fed beef production would require up to 270% more land if Americans did not reduce their consumption (Hayek and Garrett, 2018).
- In the East and Southeast Asia (ESA) region, total animal emissions are expected to increase slightly by 2030, then gradually go down until they return to early 2000’s levels by 2050.
- If direct emissions are in line with top-down estimates (scaled up by 65%), emissions per unit of meat and dairy will not decrease as drastically over time in the ESA region.
Other Important Findings
- Environmental impacts of intensive meat and dairy production are a major concern.
- Intensive methods of meat and dairy production are expanding globally and are often justified by environmental science and economic development experts.
- Reducing consumer demand for meat and dairy products, while helping producers diversify their income and shift toward food crops where possible, is recommended as a more reliable strategy for mitigating global warming.
- Improving the efficiency of pastoral systems can reduce environmental impacts, provided that improvements are accompanied by strict ecosystem conservation and do not lead to animal confinement.
- The majority of global warming emissions from animal agriculture are estimated to come from extensive, pastoral systems of production.
- Estimates of GHG emissions from animal agriculture are produced using emission models, developed by standards from the Intergovernmental Panel on Climate Change (IPCC).
- The models take detailed input information on how animals are raised in each region, such as their feed, exercise, manure disposal, and local climate, along with their productivity.
- Bottom-up animal emissions models have high precision but their overall level of accuracy is unknown.
- Top-down atmospheric estimates are a reliably independent way of testing the accuracy of bottom-up emissions models.
- Methane makes up 92% of direct animal emissions.
- The best changes to animal food production with the fewest tradeoffs would make already-existing pastoral systems more sustainable and efficient without relying on industrialization to do so.
Limitations Noted in the Document
- The models used to estimate emissions can contain multiple errors that often go unreported, which can lead to underestimation.
- The accuracy of animal emissions models is limited by the fact that the models are based on detailed input information, which must be collected at the ground-level and can be challenging.
- The accuracy of emissions estimates is limited by the use of parameters derived from small-scale studies up to 40 years old.
- Top-down atmospheric estimates, while providing an independent way to test the accuracy of bottom-up emissions models, cannot estimate indirect emissions such as feed production sourced over multiple locations.
- Top-down atmospheric measurements suggest that there are multiple problems with bottom-up emissions models, across multiple types of farmed animals and processes, which cause the models to underestimate total animal emissions in the U.S.
- Intensification may not always lead to the desired GHG savings and can lead to other negative impacts.
Conclusion
The guidance memo concludes that the environmental impacts of intensive, industrial meat and dairy production are a major concern, yet emissions are often underestimated in the US. While intensive methods of meat and dairy production are expanding globally and are often justified by environmental science and economic development experts, the memo suggests that the emissions savings potential of intensifying production may be oversold. Reducing consumer demand for meat and dairy products, while helping producers diversify their income and shift toward food crops where possible, is recommended as a more reliable strategy for mitigating global warming. The memo highlights the need for a shift in focus from intensification to a broader approach that includes reducing demand and transitioning to more sustainable practices. It underscores that the challenge of a warming world requires all economic sectors to change their strategies. The best changes to animal food production with the fewest tradeoffs would make already-existing pastoral systems more sustainable and efficient without relying on industrialization to do so. These strategies must be married with other conservation strategies, such as forest protection, which can limit unsustainable growth of production. Policymakers should be informed that intensification’s potential for limiting GHG emissions is limited. The memo suggests that governments should take seriously the need to monitor and limit emissions from animal agriculture, and bottom-up emissions models should not be used in their present state to monitor progress. In conclusion, there is a need for a shift towards policies that prioritize demand reduction and promote sustainable practices in animal agriculture, as the current trajectory may not effectively address global warming and related environmental concerns. The focus should shift from intensification to a more holistic approach that considers the broader implications of animal production on the environment and society.
IFFS Team Summary
- https://drive.google.com/file/d/1p6cb36WgmKaa_rX4d38QCGKSXGTIQfqq/view
- https://tinybeamfund.org/post/Underestimates-of-US-emissions-and-global-implications-for-industrializing-animal-agriculture
- Details how the GHGs from animal agriculture in the US are significantly underestimated.
- Animal methane emissions should be 39-90% higher according to the latest top-down atmospheric measurements.
- As opposed to “bottom up” methods
- Shifting the US back to exclusively grass-fed beef production would require up to 270% more land if Americans did not reduce their consumption.
- Although pastoral beef would reduce cropland use, this would be more than compensated for by the need for additional pastureland.
- Overall, reviews uncertainties in current calculation models, which rely on indirect methods of calculating emissions these have various shortfalls
- Measurements of atmospheric GHGs such as methane provide an accurate estimate of GHG production
- The growth of animal agriculture, idea of intensification as a mitigation strategy, may cause a large rise in GHG emissions that is underestimated
- The paper makes policy and economic recommendation