Carbon Calculators as a Tool for Assessing Greenhouse Gas Emissions from Livestock

Abstract

Carbon calculators are programs for calculating greenhouse gas emissions (a carbon footprint) from agricultural production on the farm scale. They are created on the base of the IPCC methods but have not been used in Russia yet. The purpose of this study is to analyze the effectiveness of their application to assess emissions from livestock production and to develop recommendations for their reduction. The four most common calculators, i.e., the Cool Farm Tool, the AgRE-Calc, the Farm Carbon Calculator, and Ex-Act, were selected as the study objects. Among them, the Cool Farm Tool is recognized as the most convenient and effective, while the AgRE-Calc and the Farm Carbon Calculator do not fully present the technological features of animal husbandry. Ex-Act is ill-suited for the livestock sector because it is based on changes of land use. According to model experiments, the most efficient type of farming in terms of reducing greenhouse gas emissions is full grazing, in which manure is left in the fields, and there are no expenses for production of additional feed. In this case, the emissions are reduced by 2.45 and 0.84 t СО₂-eq./head-yr for cows and horses, respectively (the Cool Farm Tool); as well as by 0.53 and 0.42 t СО₂-eq./head-yr for cows and horses, respectively (the Farm Carbon Calculator). However, this leads to extensive farm management. The second variant is changing the diet, including expenses for feed production: exclusion of green crops from the diet in case of keeping in stalls will reduce emissions by 0.05 (the AgRE-Calc) to 0.14 (the Cool Farm Tool) t СО₂-eq./head-yr, and exclusion of silage will lead to a decrease by 0.96 t CO₂-eq./head-yr, although such decisions may worsen the diet balance. To reduce greenhouse gas emissions from livestock production, it is recommended that the number of domestic animals be gradually decreased. The Farm Carbon Calculator, the AgRE-Calc, and Ex-Act significantly overestimate the intensity of greenhouse gas sequestration by forests. Because of the discrepancy in the estimates between the calculators, they should be used comprehensively.