Closing the gap in reporting anthropogenic land use emissions

The JRC hosted the IPCC Experts Meeting "Reconciling Anthropogenic Land Use Emissions" to address a critical issue in global climate science and policy: the significant discrepancy in the estimates of global land-use CO₂ emissions between global models and national greenhouse gas (GHG) inventories.  

A report (PDF) summarising the main outcomes of the meeting has been presented on 16 November during an IPCC event, at the UN Climate Change Conference (COP29) in Baku. The report will inform the Scoping meeting for the next IPCC Assessment Reports, to be held in Malaysia in December.  

The implications of different definitions 

Studies such as Grassi et al. (2021) have highlighted a gap of at least 6 billion tonnes of CO₂ per year globally (about 15% of global emissions) between the emissions reported by national GHG inventories, which inform country pledges under the Paris Agreement, and those estimated by global models used in IPCC assessments, which determine emissions pathways consistent with the Paris Agreement goals. 

This discrepancy arises primarily from differences in how anthropogenic CO₂ removals are defined, with countries using a broader definition than global models. 

A recent paper published in Nature also investigates the topic. The publication explores how the concept of net-zero CO₂ emissions to stabilise global temperature is affected by the different definitions of anthropogenic CO₂ removals. 

If the land CO₂ removals estimated with the national inventories definitions are used to offset fossil emissions, reaching net-zero emissions globally would not be enough to halt warming and reach the Paris Agreement's temperature goal.

Land use emissions in the EU  

At the EU level, land-use emissions play a critical role in reaching the 2030 and 2050 climate targets. Although land use is a net sink of CO₂ in the EU, compensating for about 7% of total EU GHG emissions, in several EU countries this sink is declining.  

This complicates the efforts towards meeting the 2030 climate target (reducing GHG emissions by at least 55% below 1990 levels) and the 2050 climate neutrality goal. A key challenge in this regard is to strike a balance between land's role in biomass production and CO₂ absorption, while increasing land’s resilience to climate change. 

Setting the ground for reconciliation  

Recognising the urgent need to address this issue, the IPCC Task Force on National GHG Inventories convened a 3-day intensive meeting, bringing together 111 experts from 46 countries, including specialists in global carbon modelling, Earth observation, and national GHG inventories. The experts discussed their approaches to identify anthropogenic land GHG fluxes and consider ways to reconcile the differences in the future.  

The main outcomes of this meeting are summarised in the IPCC Expert Meeting on Reconciling Anthropogenic Land Use Emissions report. The overarching recommendations that emerged include better communication, collaboration and transparency.  

Concrete steps require strengthening the dialogue across communities through regular workshops, further developing platforms for comparing datasets (such as the JRC-hosted “global land use carbon fluxes” hub), creating joint protocols for translating different definitions, and improving data sharing and integration. 

It is also crucial to engage experts from various communities in smaller groups at regional and national levels, using local expertise and data. This will enable a more consistent and confident assessment of the role of land use in climate progress at both global and country levels, particularly in the context of the next IPCC Assessment Report and Global Stocktake. 

Related links

Report of IPCC Expert Meeting (PDF)

Nature paper: geological Net Zero and the need for disaggregated accounting for carbon sinks