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Zhang et al. Carbon Footprints 2025, 4, 36 https://dx.doi.org/10.20517/cf.2025.29 Page 13 of 17

Figure 6. The relationships between the GHG balance and the stocking rate in yak grazing farm systems.

pastoral systems. Enteric CH emissions (34.8%-48.7% of total balance) follow allometric scaling
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2
(CH = 0.056 BW0.75, R = 0.91), yet exhibit density-dependent suppression at HSRs. Forage quality
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declines sharply beyond 1.02 yak/ha, with crude protein content dropping from 9.2% to 6.8%, reducing
methanogen activity . This creates a metabolic “sweet spot” where per-animal emissions decline, but herd-
[25]
level emissions peak due to compensatory population growth [Figure 8C]. Dung and urine patches create
[40]
biogeochemical “hotspots” covering 4.9%-8.3% of pasture area, with N O flux rates 8× background levels .
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Urine patches (0.16 m each) elevate soil NH concentrations by 15 mg/kg, driving nitrification bursts that
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+
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account for 59% of total N O emissions . Manure heaps exhibit methanogenic archaeal dominance
[28]
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-1
(Methanoculleus spp. > 70%), emitting 600-1,983 kg CH ha year -1[22] . Dry stored manure combustion
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releases 0.85 kg CO -eq/kg DM - equivalent to 12% of regional household emissions - while generating
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black carbon (BC) that accelerates glacier melt. BC deposition on QTP glaciers reduces albedo by 5%-15%,
contributing to 18% of regional ice loss . Transitioning to solar/wind energy could eliminate 89% of dung-
[41]
2
related emissions while leveraging the plateau’s abundant renewables (2,600 kWh/m irradiance, 6.5 m/s
mean wind speed). Principal component analysis identifies SOC stock (λ = 0.76) and dung patch density (λ
= 0.68) as master variables controlling emission trajectories. These findings align with catastrophe theory
models, where grazing pressure beyond 1.3 yak/ha triggers irreversible state shifts from carbon sink to
source . This nonlinear paradigm demands dynamic management strategies that prioritize critical
[42]
thresholds and leverage points.
Toward climate-smart pastoralism: integrating ecological memory with technological innovation
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Reconciling GHG mitigation (-1,720 kg CO -eq ha year under exclusion) with pastoral livelihoods
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requires a three-pillar strategy blending traditional knowledge with cutting-edge science. Internet of Things-
enabled (IoT-enabled) collars (Global positioning system (GPS) + accelerometers) optimize stocking density
in real-time by tracking yak movement and pasture Normalized Difference Vegetation Index (NDVI). Trials
in Maqu County reduced CH /kg meat by 18% while increasing ANPP by 22% through adaptive grazing
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windows . Blockchain-based pasture leases could incentivize carbon farming, with herders earning credits
[43]
[44]
for maintaining SOC stocks > 3.5% . Pyrolyzing yak dung at 450 °C produces biochar with
320 kg C ha year sequestration potential . Coupled with distributed solar microgrids (5 kW ha ), this
-1
-1
[34]
-1
eliminates 89% of manure-related emissions while providing slow-release fertilizer (N retention +37%).
Community biogas digesters could additionally offset 45% of household energy demand . Clustered
[45]