Estimates the carbon footprint from major emission sources in crop production, with source-wise breakdown and yield-scaled intensity. Uses IPCC AR6 default GWP values.

carbon_footprint(
  diesel_use = 0,
  electricity_use = 0,
  n_fertilizer = 0,
  p_fertilizer = 0,
  k_fertilizer = 0,
  pesticide_use = 0,
  seed_rate = 0,
  n2o_direct = NULL,
  ch4_emission = 0,
  yield = NULL,
  ef_diesel = 2.68,
  ef_electricity = 0.82,
  ef_n_manufacture = 4.96,
  ef_p_manufacture = 1.61,
  ef_k_manufacture = 0.57,
  ef_pesticide = 10.97,
  ef_seed = 0.58,
  gwp_n2o = 273,
  gwp_ch4 = 27,
  verbose = TRUE
)

Arguments

diesel_use

Numeric. Diesel consumption (L/ha). Default 0.

electricity_use

Numeric. Electricity consumption (kWh/ha). Default 0.

n_fertilizer

Numeric. Nitrogen fertilizer applied (kg N/ha). Default 0.

p_fertilizer

Numeric. Phosphorus fertilizer applied (kg P2O5/ha). Default 0.

k_fertilizer

Numeric. Potassium fertilizer applied (kg K2O/ha). Default 0.

pesticide_use

Numeric. Pesticide active ingredient used (kg a.i./ha). Default 0.

seed_rate

Numeric. Seed rate (kg/ha). Default 0.

n2o_direct

Numeric. Direct N2O emissions from soil (kg N2O/ha). If NULL (default), estimated using IPCC Tier 1 default: 1 percent of applied N emitted as N2O-N, then converted to N2O using factor 44/28.

ch4_emission

Numeric. Methane emission (kg CH4/ha). Default 0. Relevant for rice paddies.

yield

Numeric. Crop yield (kg/ha) for intensity calculation. Default NULL.

ef_diesel

Numeric. Emission factor for diesel (kg CO2/L). Default 2.68.

ef_electricity

Numeric. Emission factor for grid electricity (kg CO2/kWh). Default 0.82 (India grid average, CEA 2023).

ef_n_manufacture

Numeric. Emission factor for N fertilizer manufacture (kg CO2-eq/kg N). Default 4.96 (urea-based).

ef_p_manufacture

Numeric. Emission factor for P fertilizer manufacture (kg CO2-eq/kg P2O5). Default 1.61.

ef_k_manufacture

Numeric. Emission factor for K fertilizer manufacture (kg CO2-eq/kg K2O). Default 0.57.

ef_pesticide

Numeric. Emission factor for pesticide (kg CO2-eq/kg a.i.). Default 10.97.

ef_seed

Numeric. Emission factor for seed production (kg CO2-eq/kg). Default 0.58.

gwp_n2o

Numeric. Global warming potential of N2O relative to CO2. Default 273 (IPCC AR6, 100-year horizon).

gwp_ch4

Numeric. Global warming potential of CH4 relative to CO2. Default 27 (IPCC AR6, 100-year horizon).

verbose

Logical. If TRUE, prints informational messages. Default TRUE.

Value

A list with components:

total_cf

Numeric. Total carbon footprint (kg CO2-eq/ha)

cf_intensity

Numeric. Carbon footprint intensity (kg CO2-eq/kg yield), returned only when yield is provided and positive

breakdown

Data frame with columns: source, emission_kg_CO2eq, and share_pct showing the contribution of each emission source

Details

Formula: $$CF = \frac{\sum Activity_i \times EF_i}{Yield}$$

References

Lal, R. (2004). Carbon emission from farm operations. Environment International, 30(7), 981-990. doi:10.1016/j.envint.2004.01.005

Forster, P. et al. (2021). The Earth's energy budget, climate feedbacks, and climate sensitivity. In Climate Change 2021: The Physical Science Basis (IPCC AR6 WGI Chapter 7). doi:10.1017/9781009157896.009

IPCC (2019). 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Volume 4: Agriculture, Forestry and Other Land Use. ISBN:978-4-88788-232-4.

Examples

cf <- carbon_footprint(
  diesel_use = 60, electricity_use = 200,
  n_fertilizer = 120, p_fertilizer = 60, k_fertilizer = 40,
  pesticide_use = 1.5, seed_rate = 100, yield = 4500
)
#> Carbon footprint: 1628.65 kg CO2-eq/ha (GWP AR6: CH4=27, N2O=273).
cf$total_cf
#> [1] 1628.65
cf$cf_intensity
#> [1] 0.3619
cf$breakdown
#>         source emission_kg_CO2eq share_pct
#> 1       Diesel            160.80       9.9
#> 2  Electricity            164.00      10.1
#> 3 N_fertilizer            595.20      36.5
#> 4 P_fertilizer             96.60       5.9
#> 5 K_fertilizer             22.80       1.4
#> 6    Pesticide             16.46       1.0
#> 7         Seed             58.00       3.6
#> 8   N2O_direct            514.80      31.6
#> 9          CH4              0.00       0.0