Livestock Use on Public Lands in the Western USA Exacerbates Climate Change: Implications for Climate Change Mitigation and Adaptation

Abstract

Public lands of the USA can play an important role in addressing the climate crisis. About 85% of public lands in the western USA are grazed by domestic livestock, and they influence climate change in three profound ways: (1) they are significant sources of greenhouse gases through enteric fermentation and manure deposition; (2) they defoliate native plants, trample vegetation and soils, and accelerate the spread of exotic species resulting in a shift in landscape function from carbon sinks to sources of greenhouse gases; and (3) they exacerbate the effects of climate change on ecosystems by creating warmer and drier conditions. On public lands one cow-calf pair grazing for one month (an “animal unit month” or “AUM”) produces 875 kg CO2e through enteric fermentation and manure deposition with a social carbon cost of nearly $36 per AUM. Over 14 million AUMs of cattle graze public lands of the western USA each year resulting in greenhouse gas emissions of 12.4 Tg CO2e year−1. The social costs of carbon are > $500 million year−1 or approximately 26 times greater than annual grazing fees collected by managing federal agencies. These emissions and social costs do not include the likely greater ecosystems costs from grazing impacts and associated livestock management activities that reduce biodiversity, carbon stocks and rates of carbon sequestration. Cessation of grazing would decrease greenhouse gas emissions, improve soil and water resources, and would enhance/sustain native species biodiversity thus representing an important and cost-effective adaptive approach to climate change.

Bison influences on composition and diversity of riparian plant communities in Yellowstone National Park

“…Geremia et al (2019) termed bison in northern Yellowstone as “ecosystem engineers” because they are capable of modifying grasslands through their intense herbivory and migratory life history. Bison and other large ungulates influence ecosystems in four direct ways: (1) by removing vegetation through herbivory; (2) by trampling soils, biotic soil crusts, streambanks, and vegetation; (3) by redistributing nutrients via defecation and urination; and (4) by dispersing or creating favorable conditions for the establishment and dominance of exotic organisms, including noxious plant species and pathogens (Dwire et al, 1999; Fleischner, 1994; Kauffman, Beschta, et al, 2022; Kauffman, Coleman, et al, 2022). Large ungulate grazing also decreases the protective litter layer and the quantity of organic matter (and carbon) that can be incorporated into soils.…”

Practical considerations for adaptive strategies by US grazing land managers with a changing climate

“…Larger ranchers or those with spatial separation of grazing lands in different parts of the same region, in different regions, and/or states provide land managers with flexibility to match animal demand to forage availability through movement in time and space, like livestock mobility across large landscapes in Australia for reducing risk to variability in forage production in space (McAllister, 2012; McAllister et al., 2006). However, trends in reduced access to public grazing resources in the western United States (Huntsinger et al., 2010; Lewin et al., 2019) and increased public pressure to remove cattle from public lands (Kauffman et al., 2022) are notable barriers to increased mobility and the adaptation afforded by these strategies. Grazing land cooperatives offer an opportunity to collectively take advantage of social learning networks (Bennett et al., 2021; Ghorbani & Azadi, 2021; Ooi et al., 2015), and potentially improve social and material support for adaptation greater than can be individually attained within a single property.…”

Ecological benefits of strategically applied livestock grazing in sagebrush communities

“…Consequentially, there has been concern about livestock grazing in sagebrush communities. Some have called for the removal of livestock grazing from public lands because of the effects of prior grazing practices and localized heavy grazing (e.g., Beschta et al, 2012; Kauffman et al, 2022; Meyer, 2011). However, grazing occurs at moderate (30%–50% utilization of available forage) to low (<30% utilization of available forage) intensities in many sagebrush rangelands, and these areas are comparable to ungrazed areas (Anderson & Holte, 1980; Copeland et al, 2021; Davies et al, 2018; Rice & Westoby, 1978; Veblen et al, 2015).…”