Generated Summary
This perspective examines the claims of climate neutrality within the livestock sector, questioning their validity and alignment with the Paris Agreement. The study critiques the use of the GWP* metric in assessing the climate impact of livestock production, particularly methane emissions. It analyzes how industry bodies and studies have adopted goals to achieve climate neutrality, and assesses whether these claims accurately reflect the sector’s contribution to global warming. The research explores the concept of ‘climate neutrality,’ its definitions, and the implications of using GWP* to represent the warming caused by different greenhouse gases. It focuses on the potential misrepresentation of methane mitigation’s impact and its consequences for climate policy and public debate. The study delves into the challenges of defining and measuring climate neutrality within the livestock sector and its alignment with the Paris Agreement goals. The authors explain that the climate impact of sector-level methane mitigation has been misrepresented, with consequences for climate policy and related public debate. Their perspective arises primarily from their observation of the real-world consequences of the partly academic debate on different metrics of global warming potential (GWP100 and GWP*). They connect these general scientific debates on GWP* to its use, specifically, in the livestock sector.
Key Findings & Statistics
- The National Cattlemen’s Beef Association in the US claims to be able to reach climate neutrality for their beef production by 2040 [1].
- A UNECE seminar claimed the US’s dairy industry can reach climate neutrality by 2041 [2].
- Place et al. [3] state that the US dairy industry could reach climate neutrality by 2050 from annual methane (CH4) emission reductions of 1%-1.5% to that point.
- Liu et al. [4] declare that some US livestock sectors are already part of ‘a climate solution’.
- Ridoutt [5, 6] argues that Australian sheep production is already climate neutral despite its rising CO2 emissions.
- Del Prado et al [7] claim that European dairy goat and sheep production is already climate neutral.
- The established means of standardizing different GHGs into one CO2-equivalent (CO2e), representing the warming caused by CO2 over a one-hundred year period (global warming potential, GWP100), does not differentiate between long-lived climate pollutants (LLCPs) and short-lived climate pollutants (SLCPs) [12].
- Methane is a powerful GHG with anthropogenic emissions responsible for warming of approximately 0.5 °C, compared to 0.8 °C caused by carbon dioxide (CO2).
- Agriculture is the largest source of methane emissions, with the major contributing sector being livestock.
- In IPCC scenarios limiting the increase in global surface temperature to 2 °C, global CH4 emissions are reduced by around 37% (20%-60%) by 2040, compared to 2019 levels.
- In 1.5 °C scenarios with no or limited overshoot, global CH4 emissions fall 44% (31%-63%) by 2040 [17].
Other Important Findings
- The term ‘climate neutral’ has been used by various bodies to denote a state of net-zero GHG emissions, expressed in CO2 equivalence (CO2e).
- The claims of climate neutrality often depend on a shift in definition from net-zero GHG emissions to no additional warming impact (net-zero CO2we).
- The GWP* metric accounts for the effect of changes in the rate of SLCP emissions on warming over time, providing a warming equivalent (CO2we).
- GWP* reflects the fact that an increase in CH4 emissions that is sustained over decades has approximately the same temperature effect as a one-off emission pulse of CO2.
- The scope of the livestock sector and activity that is claimed to be climate neutral is not always clear, focusing mainly on CH4 emissions while overlooking CO2 and nitrous oxide (N2O).
- To maintain a state of no increase in temperature requires continued reductions in CH4 emissions at a level that balances the warming effect of further sectoral LLCP emissions.
- Article 2 of the Paris Agreement establishes a goal for the global community to limit global warming to well below 2°C compared to the pre-industrial period and to pursue efforts to achieve a 1.5 °C limit [14].
- To limit global warming, Article 4 states the ambition to balance anthropogenic emissions and removals of GHGs in the second half of this century, based on equity and in the context of sustainable development.
- The policymakers who wrote the Agreement text based this aspiration on emission pathways aggregated using GWP100 [9, 10, 15]; this GHG balance has been adopted by governing organizations as net-zero CO₂e emissions.
- The study suggests that using GWP* sub-globally does not imply that the appropriate goal for every country is to stabilize their impact on temperature.
Limitations Noted in the Document
- The study acknowledges the limitations in the scope of the livestock sector and activities when claiming climate neutrality, often focusing on CH4 emissions while overlooking other GHGs such as CO2 and nitrous oxide.
- The study’s conclusions are based on the analysis of studies and claims made by various organizations and researchers, and may be limited by the assumptions, methodologies, and data availability of those sources.
- The reliance on GWP* metric has its own limitations and doesn’t fully capture the complexities of climate change and the impacts of different GHGs.
- The study emphasizes the importance of understanding the distinction between the claims of ‘climate neutrality’ and the broader objectives of the Paris Agreement.
- The claims of climate neutrality often do not account for temporary neutrality, which is not a long-term solution.
- The study points out that the GWP* metric might be more useful to model the global effect of the changes in the global emissions of a basket of GHGs, but this has limitations as a guide for effective mitigation of GHGs when applied at sectoral level.
Conclusion
The core argument of the document is that claims of climate neutrality within the livestock sector are often misleading and misaligned with the goals of the Paris Agreement. The authors conclude that the studies in table 1 have a distorted understanding of the climate impact of livestock production. They emphasize that the claimed states of climate neutrality are temporary and not aligned to the wider outcomes of the Paris Agreement. The authors highlight that the ambition of the Paris Agreement is clear in a political context: to stop global warming by fairly achieving net-zero emissions of GHG while fostering sustainable development (Article 2 and Article 4). They find that the sector-level application of GWP* in effect trades Article 2 off against Article 4. The document suggests that the focus on temperature stabilization, as promoted by some studies, is insufficient for aligning with the Paris Agreement’s goals. The authors state that the climate neutrality claims exploit a marginal warming blind spot: two sectors that have both reached climate neutrality could be responsible for very different ongoing contributions to global warming. This contrasts with the need for global CO2 mitigation and net-zero CO2 emissions at the global level. The authors also warn that if the thinking about climate neutrality in the livestock sector is applied to the fossil fuel sector, the results would be equally misleading. In essence, natural gas (methane) producers could use a reduction in leakages in their processes to claim climate neutrality because the resulting ‘cooling’ offsets the warming caused by the continued combustion of the used gas. In summary, this perspective calls for a more critical and comprehensive approach to evaluating the climate impact of the livestock sector, particularly in the context of climate policy. The authors challenge the oversimplified narratives and call for a more robust understanding of GHG emissions and their effects. The main point of the document is that using GWP* alone to justify a sub-global goal of no additional warming does not go far enough for some sectors. It is also inequitable, and climate neutrality claims, as outlined in table 1 and related publicity, show clearly how this grandfathering principle can be used to argue for maintaining high levels of the production and consumption of animal products.