Chapter 4: Accounting Negative Emissions. How Difficult Could It Be?

Negative emissions will play a key role in our ability to reach ambitious climate targets. Although carbon accounting appears a simple task, the lack of agreed definition, accounting methodologies and assumptions will hinder decision makers from appropriately and efficiently incentivising, deploying, monitoring and verifying those emissions. This chapter highlights the importance of appropriately defining and accounting emissions by exploring four key challenges for carbon accounting of negative emissions, namely: assessing permanence, accounting for the temporal distribution of emissions and removals, choosing time horizons, and conflating CO₂ avoidance and CO₂ negativity.