A critical review of avoided conversion of grassland and shrubland methodologies

This paper reviews the state of avoided conversion of grassland and shrubland projects in nature-based solutions, by critically reviewing some of the leading protocols for quantifying emission reductions (ERs) in this sector and discussing some of their methodological and logistical flaws. We reviewed the available literature at a global scale over the past decade. By reviewing methodologies like Verra's VCS VM0009, American Carbon Registry's ACoGS methodology, and Climate Action Reserve's US Grasslands protocol, this review identifies common concerns such as inadequate guidance on field data collection, the exclusion of grazing from baseline scenarios, and failure to properly account for ecological factors affecting carbon fluxes in grasslands and savannas. This review is the first of its kind to critically evaluate the limited options for ACoGS—a critical area of nature-based climate solutions—through the lens of connecting methodological processes to real-life applications. To improve upon the identified flaws, we also provide a brief snapshot of elements which must go into making an improved protocol, such as expanding the scope of methodologies to include common drivers of land-conversion like grazing, expanding the utilization of remote sensing technologies to monitor project activities, and exploring the utilization of other ecological measures to quantify carbon fluxes, such as ecosystem energy balances. The findings of this review will be directly impactful for project developers, proponents (landowners) looking to get involved in carbon markets, to registries/standards, and rating agencies which are emerging standard bearers of integrity that seek to better understand market forces and the evolving science behind these methodologies.