Existing strategies, diligently applied, could mitigate livestock methane emissions enough to help the sector limit its share of global warming to the 1.5 °C target by 2030. That is the main conclusion of a recent meta-analysis published in The Proceedings of the National Academy of Sciences (PNAS). This positive news comes with the provision that the most effective mitigation strategies be fully adopted.
“Only concerted action will help countries meet their targets. It is crucial that adoption barriers are identified and removed, and the identified strategies implemented”, says associate professor Jan Dijkstra from Wageningen University & Research. “Such barriers may include availability of mitigation technologies, in particular in rural areas, and costs of proposed strategies or technolgies”. Dijkstra is one of the twenty four experts from top-level institutes around the world who reviewed hundreds of peer-reviewed studies for strategies designed to decrease product-based and absolute enteric methane emissions by ruminants.
Strategies to reduce methane emission
Because of ruminants’ multiple uses in low income countries and their contribution to the Sustainable Development Goals, the authors focused on strategies that reduce enteric methane production without reducing animal productivity. They identified three strategies related to feed management that could reduce methane emission per unit of meat or milk by an average of twelve percent while increasing animal productivity. The strategies were increasing feed intake level, having ruminants graze on less mature grass, and feeding increasing levels of concentrate.
In addition, they identified five strategies that on average not only reduced methane per unit of product by seventeen percent, but also reduced absolute methane emission by more than twenty percent, with relatively minor effects on animal productivity. The strategies include supplementing animals with methane inhibitors, oils and fats, oilseeds, nitrate (electron acceptors) as well as feeding tanniferous forages.
Spoiler alert: current strategies can meet short-term targets, but further research is needed to develop strategies sufficient to meet longer-run targets as well. Additional strategies, or improvement of efficacy of current strategies, will be needed due to the projected increase in global demand of livestock products, to stay on track for 2050. The authors looked at how the implementation of the identified strategies could help to reduce global, European and African methane emissions by livestock.
In Europe, they found multiple scenarios that did not require full adoption of the most effective strategies to meet the 2030 targets, and that full adoption of the two most effective strategies could meet the 2050 target.
In Africa, by contrast, the identified strategies would not be sufficient to fully meet either the 2030 or 2050 target. “This is because of Africa’s growing human population and per capita demand for animal products, which are expected to lead to a substantial increase in livestock production and greenhouse gas emissions”, says researcher and co-author André Bannink, “and also the reliance on ruminant production systems in many regions with the system’s features posing much stronger limitations to the implementation of some strategies”.