SUMMARY

Carbon markets are crucial mechanisms for achieving the Paris Agreement goal of limiting the global temperature increase to between 1.5 to 2o above pre-industrial levels.  Uncertainty and lack of trust currently constrain investment in these markets, however, which is a major factor contributing to depressed carbon credit prices.

Atmospheric-based greenhouse gas (GHG) monitoring can reduce this uncertainty.  Atmospheric-based monitoring measures GHG fluxes into and out of the atmosphere. Positive fluxes correspond to emissions, negative fluxes to removals. By reflecting actual mitigation outcomes, GHG flux measurements complement activity-based methods currently in widespread use, which estimate emissions and removals based on activity data and emission factors.

Atmospheric-based GHG monitoring draws on over 60 years of scientific research, infrastructure development, operations and data.  This report summarizes results from an extensive review of the scientific literature, which shows that activity-based estimates – while reasonably accurate for combustion and other controlled processes – can diverge substantially from atmospheric measurements in cases where emissions sources and removal processes are spatially-extensive, diverse and/or dynamic.  Such cases include oil and gas production, solid waste management, urban and agricultural areas, and nature-based atmospheric GHG removal.