Generated Summary
This perspective examines the validity of climate neutrality claims made by livestock industry bodies. The study focuses on how these claims are based on the application of the GWP* metric and whether they align with the Paris Agreement. The research approach involves a critical analysis of existing studies and the definitions of “climate neutrality”, particularly in the context of livestock sectors. The methodology used is to examine the basis of claims that livestock sectors can readily become ‘climate neutral’. This involves first examining the term ‘climate neutrality’ and how the recently developed GWP* metric has been applied at sector level. This is followed by consideration of the claims that such climate neutrality aligns sectors to the Paris Agreement. The study aims to clarify how the use of GWP* and sector-level methane mitigation are represented. The scope includes an overview of climate neutrality definitions and metrics, temporary neutrality, and the alignment of climate neutrality goals with the Paris Agreement. The authors 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 claim to be able to reach climate neutrality for their beef production by 2040.
- It was claimed at a UNECE seminar that the US’s dairy industry can reach climate neutrality by 2041, despite remaining a significant source of greenhouse gases (GHGs).
- 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.
- Ridoutt et al [8] state that Australian lamb currently has a ‘negative climate footprint.
- Methane is 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.
- 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.
Other Important Findings
- The term ‘climate neutral’ has shifted from net-zero GHG emissions (net-zero CO2e), which was used in the preparation of the Paris Agreement, to no additional warming impact (net-zero CO2we).
- The climate neutrality claims depend on how the temperature effect of reductions in methane (CH4) are handled within a basket of GHG emissions.
- The GWP100 metric does not differentiate between long-lived climate pollutants (LLCPs) and short-lived climate pollutants (SLCPs).
- GWP* accounts for the effect of changes in the rate of SLCP emissions on warming over time.
- 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 studies claiming climate neutrality for livestock sectors are not always clear about the scope.
- The use of GWP* at a sectoral level might misalign sectors with the Paris Agreement’s temperature goals.
- The use of GWP* can lead to a “grandfathering” principle, potentially allowing sectors with high methane emissions to maintain high levels of production.
- The climate neutrality outcome in Place et al. [3] differs from that expected by the makers of GWP*.
Limitations Noted in the Document
- The study primarily observes the real-world consequences of the debate on GWP100 and GWP*, focusing specifically on the livestock sector.
- The definition of ‘climate neutrality’ and the scope of activities considered climate neutral may be unclear.
- The reliance on the GWP* metric may misrepresent the impact of sector-level methane mitigation, with consequences for climate policy and related public debate.
- The study acknowledges that the Paris Agreement commitments are made by countries (Parties) rather than business sectors, which is an important distinction.
- The focus on temperature stabilization at a sectoral level using GWP* may be misaligned with the overall goals of the Paris Agreement.
Conclusion
The studies in table 1 have a distorted understanding of the climate impact of livestock production. The claimed states of climate neutrality are temporary and are not aligned to the wider outcomes of the Paris Agreement. The ambition of the Paris Agreement is clear in a political context: to stop global warming (Article 2) by fairly achieving net-zero emissions of GHG (Article 4) while fostering sustainable development. The introduction of the ambiguous term ‘climate neutrality’ into discussions about implementation has opened the door to the exploitation of perceived inconsistencies between temperature stabilization and achieving net-zero emissions. The sectoral positions show that changing the metric used from GWP100 to GWP*, whilst keeping the same timeline for GHG balance, risks an inconsistency in policy action between Articles 2 and 4. The authors conclude that the use of GWP* alone does not guide us to cost-effective mitigation because it does not account for ‘marginal warming’. 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. It is now critical that policymakers advance swiftly to adopt national and sectoral mitigation strategies consistent with the Paris Agreement.