Social cost of methane: Method and estimates for Indian livestock

Abstract

The quantitative assessment of climate change damage due to an additional unit of greenhouse gases emissions (mainly carbon di-oxide, CO2) is termed as the Social Cost of Carbon (SCC). Published literature primarily focused on the SCC of CO2 emissions, neglecting other greenhouse gases (GHGs). The social cost assessment for other GHGs especially CH4 is also needed as it is the 2nd highest emitted GHG after CO2 with high global warming potential. The quantitative assessment of climate change damage per additional unit of CH4 can be termed as Social Cost of Methane (SCM). In the present study, the SCM (in CO2e unit) has been estimated for the Indian livestock using Integrated Assessment Model (IAM) and system dynamic approach. Different livestock growth scenarios viz. Business as usual (BAU), modified scenarios (MS I, MS II and MS III) have been proposed for SCM calculation (cost per ton CO2e CH4) through 2017 to 2032. The SCM for 2017 is $62 ̶ $1150 and is projected to be $77 ̶ $1438 in 2032. The highest SCM is in BAU ($1150 in 2017 and $1438 in 2032) and the lowest in MS I ($62 in 2017 and $77 in 2032). The differences in SCM values are due to the different population size of livestock and CH4 emission rate. Results and findings of the study suggest that the CH4 even emitted in small quantity has a significant impact on climate and hence should not be neglected in climate change mitigation policies. The SCM is a metric tool which helps to design the appropriate policies for reducing CH4 emission from livestock. The developed tool can also be applicable to estimate the social cost for other GHGs for market-based policy development.