Reconciling global-model estimates and country reporting of anthropogenic forest CO 2 sinks

Abstract

Achieving the long-term temperature goal of the Paris Agreement requires forest-based mitigation. Collective progress towards this goal will be assessed by the Paris Agreement s Global stocktake. At present, there is a discrepancy of about 4 GtCO 2 yr -1 in global anthropogenic net land-use emissions between global models (reflected in IPCC assessment reports) and aggregated national GHG inventories (under the UNFCCC). We show that a substantial part of this discrepancy (about 3.2 GtCO 2 yr -1 ) can be explained by conceptual differences in anthropogenic forest sink estimation, related to the representation of environmental change impacts and the areas considered as managed. For a more credible tracking of collective progress under the Global stocktake, these conceptual differences between models and inventories need to be reconciled. We implement a new method of disaggregation of global land model results that allows greater comparability with GHG inventories. This provides a deeper understanding of model inventory differences, allowing more transparent analysis of forest-based mitigation and facilitating a more accurate Global stocktake. (c) 2018, The Author(s), under exclusive licence to Springer Nature Limited.