Critical adjustment of land mitigation pathways for assessing countries’ climate progress

• Published in: Nature climate change Vol. 11; no. 5; pp. 425 - 434
• Main Authors: Grassi, Giacomo, Stehfest, Elke, Rogelj, Joeri, van Vuuren, Detlef, Cescatti, Alessandro, House, Jo, Nabuurs, Gert-Jan, Rossi, Simone, Alkama, Ramdane, Viñas, Raúl Abad, Calvin, Katherine, Ceccherini, Guido, Federici, Sandro, Fujimori, Shinichiro, Gusti, Mykola, Hasegawa, Tomoko, Havlik, Petr, Humpenöder, Florian, Korosuo, Anu, Perugini, Lucia, Tubiello, Francesco N., Popp, Alexander
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.05.2021; Nature Publishing Group
• Subjects: 704/106/47; 704/47; Carbon footprint; Climate; Climate Change; Climate Change/Climate Change Impacts; Climate models; Decarbonization; Earth and Environmental Science; Emission analysis; Emission inventories; Emissions control; Environment; Environmental Law/Policy/Ecojustice; Estimates; Fluxes; Global warming; Greenhouse effect; Greenhouse gases; Inventories; Land use; Mitigation; Net zero; Paris Agreement
• ISSN: 1758-678X; 1758-6798
• DOI: 10.1038/s41558-021-01033-6

Mitigation pathways by Integrated Assessment Models (IAMs) describe future emissions that keep global warming below specific temperature limits and are compared with countries’ collective greenhouse gas (GHG) emission reduction pledges. This is needed to assess mitigation progress and inform emission targets under the Paris Agreement. Currently, however, a mismatch of ~5.5 GtCO 2  yr −1 exists between the global land-use fluxes estimated with IAMs and from countries’ GHG inventories. Here we present a ‘Rosetta stone’ adjustment to translate IAMs’ land-use mitigation pathways to estimates more comparable with GHG inventories. This does not change the original decarbonization pathways, but reallocates part of the land sink to be consistent with GHG inventories. Adjusted cumulative emissions over the period until net zero for 1.5 or 2 °C limits are reduced by 120–192 GtCO 2 relative to the original IAM pathways. These differences should be taken into account to ensure an accurate assessment of progress towards the Paris Agreement. There is a mismatch between emission estimates from global land use calculated from IAMs and countries’ greenhouse gas inventories. This study presents a method for reconciling these estimates by reallocating part of the land-use sink, facilitating progress assessment towards climate goals.