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Run Enteric Methane (CH4) Emissions Module Pipeline

Source: R/run_emissions_enteric_module.R
run_emissions_enteric_module.Rd

Calculates daily enteric methane emissions by cohort (kg CH4/head/day) using a Tier 2 IPCC approach, by applying species-, cohort- and diet-specific methane conversion factors (ym).

Usage

run_emissions_enteric_module(cohort_level_data, show_indicator = TRUE)

Arguments

cohort_level_data

data.table. Cohort-level input table with the following data requirement:

herd_id

Character. Unique identifier for the herd, repeated for each cohort belonging to the same herd.

species_short

Character. Code identifying the livestock species. Supported values include:

  • PGS: pigs

  • CML: camels

  • CTL: cattle

  • BFL: buffalo

  • SHP: sheep

  • GTS: goats

cohort_short

Character. Sex- and age-specific cohort code describing the production stage of the animals. Supported values include:

  • FA: adult females (from age at first parturition)

  • FS: sub-adult females (from weaning to age at first parturition)

  • FJ: juvenile females (from birth to weaning)

  • MA: adult males (from age at first breeding)

  • MS: sub-adult males (from weaning to age at first breeding)

  • MJ: juvenile males (from birth to weaning)

ration_digestibility_fraction

Numeric. Average digestibility of the feed ration, expressed as ratio of digestible (or metabolizable, for poultry) to gross energy content (fraction).

ration_gross_energy

Numeric. Average gross energy content of the diet (MJ/kg DM).

ration_intake

Numeric. Average daily dry matter intake of feed (kg DM/head/day).

ch4_mitigation_factor

Numeric. Optional. Multiplicative mitigation factor applied to baseline enteric methane (CH4) emissions (dimensionless). If not provided, a default value of 1 (no mitigation) is used. Values lower than 1 represent proportional reductions (e.g., 0.90 = 10% reduction). This factor can represent mitigation measures with a direct effect on enteric methane emissions, such as the use of feed additives or methane inhibitors.

show_indicator

Logical. Whether to display progress indicators during calculations. Defaults to TRUE.

Value

A data.table with the original input columns plus the following new variables:

ch4_mitigation_factor

Added by the function if not provided as input.

ch4_conversion_factor_ym

Numeric. Methane (CH4) conversion factor (ym), representing the percentage of gross energy of the feed ration that is converted to CH4 (percentage).

ch4_enteric

Numeric. Average daily enteric methane (CH4) emissions (kg CH4/head/day).

Details

This function represents the intermediate module of the Global Livestock Environmental Assessment Model (GLEAM) computational pipeline run_gleam() to estimate enteric methane emissions and performs the following calculation sequence:

  1. If ch4_mitigation_factor is not provided in the input data, it is set to 1 (no mitigation).

  2. The methane conversion factor (ym) is computed using calc_conversion_factor_ym.

  3. Daily enteric methane emissions are computed using calc_ch4_enteric.

References

IPCC. (2019). 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Chapter 10: Emissions from Livestock and Manure Management, Equation 10.21.

IPCC. (2006). 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Chapter 10: Emissions from Livestock and Manure Management, Equation 10.21.

See also

run_gleam, calc_conversion_factor_ym, calc_ch4_enteric

Examples

# \donttest{
# Load example input (6 herd_ids, cohort-level; only required columns)
input_path <- system.file(
  "extdata/run_modules_examples/emissions_enteric_input_chrt_data.csv",
  package = "gleam"
)
emissions_enteric_input_chrt_data <- data.table::fread(input_path)
results <- run_emissions_enteric_module(
cohort_level_data = emissions_enteric_input_chrt_data
)
#> 🕒 Calculating enteric methane emissions, please wait…
#> ✔ Enteric methane emissions calculation complete.
# }