Abstract
Ruminant livestock are an important source of anthropogenicmethane (CH_4). Decreasing the emissionsof enteric CH_4 from ruminant production is strategicto limit the global temperature increase to 1.5℃ by2050. Research in the area of enteric CH_4 mitigationhas grown exponentially in the last 2 decades, withvarious strategies for enteric CH_4 abatement beinginvestigated: production intensification, dietary manipulation(including supplementation and processingof concentrates and lipids, and management of forageand pastures), rumen manipulation (supplementationof ionophores, 3-nitrooxypropanol, macroalgae, alternativeelectron acceptors, and phytochemicals), and selectionof low-CH_4-producing animals. Other enteric CH_4mitigation strategies are at earlier stages of research butrapidly developing. Herein, we discuss and analyze thecurrent status of available enteric CH_4 mitigation strategieswith an emphasis on opportunities and barriersto their implementation in confined and partial grazingproduction systems, and in extensive and fully grazingproduction systems. For each enteric CH_4 mitigationstrategy, we discuss its effectiveness to decrease totalCH_4 emissions and emissions on a per animal productbasis, safety issues, impacts on the emissions of othergreenhouse gases, as well as other economic, regulatory,and societal aspects that are key to implementation.Most research has been conducted with confinedanimals, and considerably more research is needed todevelop, adapt, and evaluate antimethanogenic strategiesfor grazing systems. In general, few options arecurrently available for extensive production systemswithout feed supplementation. Continuous research anddevelopment are needed to develop enteric CH_4 mitigationstrategies that are locally applicable. Informationis needed to calculate carbon footprints of interventionson a regional basis to evaluate the impact of mitigationstrategies on net greenhouse gas emissions. Economicallyaffordable enteric CH_4 mitigation solutions areurgently needed. Successful implementation of safe andeffective antimethanogenic strategies will also requiredelivery mechanisms and adequate technical supportfor producers, as well as consumer involvement and acceptance.The most appropriate metrics should be usedin quantifying the overall climate outcomes associatedwith mitigation of enteric CH_4 emissions. A holistic approach is required, and buy-in is needed at all levels ofthe supply chain.
NETL
NSTL
Elsevier