Increased transparency in accounting conventions could benefit climate policy

Abstract

Greenhouse gas accounting conventions were first devised in the 1990’s to assess and compare emissions. Several assumptions were made when framing conventions that remain in practice, however recent advances offer potentially more consistent and inclusive accounting of greenhouse gases. We apply these advances, namely: consistent gross accounting of CO _2 sources; linking land use emissions with sectors; using emissions-based effective radiative forcing (ERF) rather than global warming potentials to compare emissions; including both warming and cooling emissions, and including loss of additional sink capacity. We compare these results with conventional accounting and find that this approach boosts perceived carbon emissions from deforestation, and finds agriculture, the most extensive land user, to be the leading emissions sector and to have caused 60% (32%–87%) of ERF change since 1750. We also find that fossil fuels are responsible for 18% of ERF, a reduced contribution due to masking from cooling co-emissions. We test the validity of this accounting and find it useful for determining sector responsibility for present-day warming and for framing policy responses, while recognising the dangers of assigning value to cooling emissions, due to health impacts and future warming.

Keywords

• emissions accounting
• agriculture emissions
• deforestation
• effective radiative forcing
• emission sectors
• animal agriculture