How we measure and account for carbon and other greenhouse gas emissions, is the basis for how we track progress towards climate change mitigation efforts.

Carbon accounting typically includes two aspects: physical flows of carbon to and from the atmosphere, but also “non-emissions” which are measured or assumed changes in emissions relative to a historical or counterfactual baseline.

In short, carbon accounting focuses on emissions and removals on one side, and reduction and avoidance of emissions on the other.

Carbon accounting is more than just technical measurements, but also embodies how we think about responsibility and how we assign liability for climate action or failures to act.   

In short:

• Carbon accounting is needed to correctly measure responsibility to act, not only to measure physical flows or carbon. 

• Emissions, reductions, avoidance, and removals of greenhouse gases are fundamentally distinct activities that must be accounted for separately.  

Global warming is affected by the total, physical quantity of greenhouse gases (GHGs) emitted to and removed from the atmosphere, regardless of where, how, or why those emissions and removals occur. Accurately measuring physical stocks and flows of greenhouse gases, for both natural and human-led processes, is necessary to understand how these activities result in changes in atmospheric greenhouse gas concentrations. This work is necessary to understand what needs to be done to stop GHGs concentrations increasing further. 

Carbon accounting is an intermediary between physical carbon flows and our motivation to change those flows. While measurement of physical GHG stocks and flows is a fundamental component of carbon accounting, the goal is to quantify responsibility for emissions and the actions taken to reduce them. Such ownership of GHG emitting and reducing activities is used to incentivise activities that decrease emissions and increase removals, and to penalise activities that increase emissions and/or decrease removals.  

The purpose of carbon accounting is to ensure an informed approach to assigning responsibility and generating accountability for emitting greenhouse gases.