Report of the IPCC Expert Meeting on Reconciling Anthropogenic Land Use Emissions

IPCC (2024). Report of the IPCC Expert Meeting on Reconciling Anthropogenic Land Use Emissions. Institute for Global Environmental Strategies (IGES) on behalf of the Intergovernmental Panel on Climate Change (IPCC) , Hayama, Japan.

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Abstract

Land-based mitigation is a key element to reaching the Paris Agreement’s temperature and net zero greenhouse gas (GHG) emissions goal. However, recent studies have revealed a significant discrepancy in global land-use CO2 emissions between global models, used to determine the net-zero pathways in the IPCC Assessment Reports, and national GHG inventories as well as country climate pledges, used to assess compliance with the Paris Agreement. This gap, equal to about 6-7 billion tonnes CO2 per year globally (equivalent to ca. 15% of global CO2 emissions), mainly reflects differences in how anthropogenic CO2 removals are defined, with countries using a broader definition than global models.

In other words, there are different communities working on the same topic but using different approaches, like different “languages”, each valid in its context but incompatible in a dialogue without translation. While global models consider as “anthropogenic” only those emissions and removals associated to direct human-induced effects (e.g., land-use change, harvest, regrowth), national inventories include both direct and, often, most indirect human-induced effects (e.g., fertilization effect on vegetation growth due to increased atmospheric CO2 concentration, Nitrogen deposition, changes in temperature and length of growing season) on land defined as “managed”, i.e. subject to human influence. Specifically, managed land is where human interventions and practices have been applied to perform production, ecological or social functions, including conservation and fire protection activities. Emissions and removals for unmanaged lands are not reported in national inventories. The land areas considered by the different approaches are also different.

Global models consider only the relatively small areas where the direct effects occur, while inventories consider a broader managed land area, often including the whole country. Under the Paris Agreement’s Global Stocktake, these differences have important implications for the assessment of where we are compared to where we should be. To start addressing this problem, the IPCC Task Force on National GHG Inventories convened an Expert Meeting on “Reconciling Anthropogenic Land Use Emissions” at the European Commission’s Joint Research Centre, Ispra (Varese, Italy), from July 9-11, 2024. The meeting gathered 111 experts (85 in person and 26 online) from 46 countries, representing the main communities involved in this topic: global carbon modelling, Earth observation, and national GHG inventories. The Expert Meeting was preceded by a preparatory Webinar (24 June 2024) attended by 80 experts, where the key concepts and methods used by the various communities were illustrated.

Item Type:	Other
Research Programs:	Energy, Climate, and Environment (ECE) Energy, Climate, and Environment (ECE) > Integrated Assessment and Climate Change (IACC) Energy, Climate, and Environment (ECE) > Sustainable Service Systems (S3)
Depositing User:	Michaela Rossini
Date Deposited:	13 Nov 2024 09:49
Last Modified:	13 Nov 2024 09:49
URI:	https://pure.iiasa.ac.at/20115

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