OBSERVER: Understanding the role of CLMS in carbon removal monitoring
sonia
The EU’s commitment to climate neutrality by 2050, set out in the European Climate Law, has made the accurate monitoring and verification of carbon removal a scientific and political priority. The Copernicus Land Monitoring Service (CLMS) provides harmonised land cover datasets and products which support more detailed and geographically explicit greenhouse gas reporting under the Land Use, Land-Use Change, and Forestry (LULUCF) Regulation. Beyond Europe, open-access Earth Observation data from Copernicus is increasingly supporting countries in strengthening their monitoring and reporting under the United Nations Framework Convention on Climate Change (UNFCCC). In this Observer, we explore the current and future role of CLMS in carbon removal monitoring.
The European Union (EU) has developed one of the world’s most comprehensive and ambitious environmental and climate policy frameworks. At its centre is the legally binding European Climate Law, which commits all Member States to climate neutrality by 2050.
Achieving this target requires significant reductions in emissions across all sectors and deliberate carbon removal to balance residual emissions. Carbon removal, which occurs naturally in forests, grasslands, peatlands, and marine ecosystems, involves extracting CO₂ from the atmosphere and storing it in forms that minimise the risk of re-release.
Carbon removal in the EU
Land-based carbon removal is mainly provided by ecosystems such as forests, grasslands, and peatlands, whose ability to absorb CO₂ depends on their extent, condition, age, management, and resilience to disturbance. Unfortunately, the capacity of these land carbon sinks has declined in many parts of Europe in recent decades. Climate change has played an increasing role in this decline through factors such as wildfires, wind and storm damage to trees, and pest outbreaks, but human factors including land use and management practices also remain key drivers. Several EU legislative frameworks address land-based carbon removal, in particular the Land Use, Land-Use Change, and Forestry (LULUCF) Regulation, which sets rules for how land-based removals are accounted for and assessed.
Through the LULUCF Regulation, Europe is modernising its land carbon reporting system. By 2028, all carbon pools must use at least Tier 2 methods, which means using country-specific data and tracking land use change in a geographically explicit way, with changes mapped to specific locations rather than only reported as national totals. By 2030, the most sensitive landscapes (carbon-rich areas such as peatlands and forests) and those most exposed to the impacts of climate change must be reported using Tier 3 methods. Tier 3 methods require advanced modelling, repeated field measurements, and high-resolution spatial data, which Earth Observation (EO) provides.
“National greenhouse gas inventories are the backbone of credible climate policymaking.”
-Lucia Perugini
Carbon Farming Certification and LULUCF expert,
European Environment Agency (EEA)
Lucia Perugini, Carbon Farming Certification and LULUCF expert at the European Environment Agency (EEA), explains that “In essence, Europe is transforming its greenhouse gas inventory from a compliance exercise into the kind of strategic climate support system required to design effective policies and to credibly track progress towards its 2030 and 2050 climate objectives.”
The role of CLMS in Europe
The Copernicus Land Monitoring Service (CLMS) provides more than 250 open access land cover and land use datasets, many of which have relevance to assessing carbon removals in Europe. These data are harmonised across their entire coverage area, making comparisons between areas and between years transparent and uniform for all users. Some data products, such as the bio-geophysical variables, are delivered in near-real time, while others are provided as distinct status layers which are updated at regular intervals.
Copernicus data have great potential for strengthening LULUCF monitoring, reporting, and verification across EU Member States. Sentinel-1 and Sentinel-2 imagery, together with CLMS products such as CLCplus Backbone and the CLMS High Resolution Layers are increasingly supporting more consistent land use mapping. The CLMS High Resolution Layers, which include data products such as Tree Cover & Forests, Small Landscape Features (SLF), Grasslands, Croplands, and Imperviousness, are currently all provided at 10m (or 5m in the case of SLF) spatial resolution with time series extending back 8 to 20 years. Historically, these layers were updated every 3 years, but recently Tree Cover & Forests, Grasslands, and Croplands have moved to annual update cycles.
Across the EU, the use of CLMS data in LULUCF monitoring varies. A review of national inventory reports conducted by the EEA shows that around 17 Member States currently reference CLMS products in their land-use reporting workflows. In most cases, this use centres on the long-standing CORINE Land Cover (CLC) dataset and tends to occur at lower level in national monitoring hierarchies. Countries typically rely first on detailed national land-use datasets and forest inventories, subsequently turning to CLMS products for consistency checks, spatial verification, or to address data gaps. Some Member States also integrate High Resolution Layers alongside national sources within more complex estimation pipelines. While adoption of CLMS products is growing, differences between land cover and the land use definitions required under LULUCF reporting mean that CLMS products often complement rather than replace national systems.
In 2023, CLMS began the rollout of the CLCplus product suite, developed in collaboration with the European Environment Agency (EEA) and the EAGLE expert group to directly address EU policy needs. CLCplus Backbone provides land cover mapping at 10m resolution with updates every two years, a significant improvement over CORINE Land Cover’s six-year cycle. Building on this foundation, CLCplus Core provides a database and web mapping application through which customised products known as CLCplus Instances can be generated, each of them tailored to the requirements of specific EU policies and Member State stakeholders.
The EEA plans to provide as its first regular output an Instance designed specifically to support users with their LULUCF reporting obligations. Tobias Langanke, a Copernicus and LULUCF expert at the EEA, and one of the main developers of the LULUCF Instance says: “Essentially, it is a map composed of various CLMS datasets designed to provide the best possible EU-wide approximation of the main land use classes which countries are required to report on every year.”
Under the LULUCF Regulation, Member States must provide annual reports of how much area is taken up within their national borders by land cover classes such as forest, croplands, wetlands, grasslands, and urban fabric, as well as track land cover changes over time. These numbers are then used to derive carbon removal estimates. “Our LULUCF Instance therefore acts as an independent dataset to support countries and offer an independent geospatial ‘check’ for what the countries report,” Langanke says.
CLMS outside Europe
The contribution of CLMS to carbon removal monitoring is not limited to Europe. As Alessandro Cescatti, expert at the Joint Research Centre (JRC), observes: “The demand for spatially explicit carbon removal data is no longer just European, it is global, and it is driven directly by international reporting obligations.” Under frameworks such as the UNFCCC, countries are increasingly required to move towards Tier 3 methodologies, meaning spatially explicit, map-based reporting underpinned by advanced modelling and repeated measurements. “At that level of detail, satellites are not optional, they are the only instruments capable of delivering the required spatial and temporal consistency.”
CLMS provides a suite of bio-geophysical variables with global coverage, delivered at high temporal frequency. Unlike static land cover layers, these enable near-real-time observation of vegetation productivity, hydrological stress, and seasonal ecosystem dynamics, including variables such as Leaf Area Index (LAI), Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), Fractional Vegetation Cover (FVC), Land Surface Temperature (LST), Soil Water Index (SWI), Dry Matter Productivity (DMP), and Evapotranspiration.
In the context of carbon removal, these datasets are important because they capture ecosystem functioning rather than only structural extent. FAPAR and LAI are closely linked to photosynthetic activity and primary production, while DMP reflects above-ground biomass accumulation. Evapotranspiration can help detect vegetation stress, which influences carbon uptake. However, these are precursor signals of carbon uptake, not direct measurements of carbon removal. “Unfortunately, organic carbon stored in biomass and soils cannot be seen directly from space. It can only be derived indirectly through models integrating multiple observations.”, Cescatti emphasises.
Complementing these dynamic products, the new Land Cover and Forest Monitoring product (LCFM) provides a harmonised land cover and forest tree cover dataset, enabling consistent detection of land use change, soil sealing, deforestation, reforestation, and vegetation degradation worldwide.
Different considerations for different scales
At project level, fine spatial detail is needed to calculate the impact of, for example, the way a specific forest is managed. At national level, consistency over decades and coherence with land use categories become central.
Noting the importance of conceptual alignment, Cescatti points out that “land cover and land use are not the same. A harvested forest may temporarily lose canopy cover and disappear from a forest cover map, yet in greenhouse gas inventories, it remains classified as forest land under management.”
At both project and national scales, uncertainty management is another key factor. “In carbon accounting, uncertainty is not a side issue, it is part of the accounting framework itself“, Cescatti stresses. Estimating carbon removal remains technically demanding. Annual biomass increases are often just a few percent, and detecting such small changes requires the uncertainty of the measurement to be smaller than the signal itself.
Niger and Ghana illustrate how these needs differ in practice. In the Sahel, where land degradation, rainfall variability, and fragmented data collection make consistent monitoring difficult, CLMS land cover time series and vegetation productivity indicators provide the baselines required to assess restoration at the project level. In Ghana, where forest conservation must remain coherent alongside economic development over decades, CLMS Global Land Cover and Tree Cover Density products can provide harmonised, regularly updated baselines to support the development of national inventories.
The future of carbon removal monitoring
Across Europe, CLMS products are already starting to see use by Member States in a carbon removal context, but the work is just beginning. As the LULUCF Regulation drives Member States toward Tier 2 and Tier 3 reporting, the demand for data which goes beyond land cover mapping will only grow. Developing products and methodologies which can reliably support land use accounting at the precision the regulation now demands, remains one of the central challenges for the CLMS community in the years ahead.
Globally, the picture is similar. International reporting obligations under frameworks such as the UNFCCC are pushing countries toward Tier 3 reporting, and many lack the national monitoring infrastructure to meet these requirements independently. CLMS global products are already contributing to filling this gap in regions like West Africa and the Sahel, providing harmonised baselines in areas where fragmented monitoring systems would otherwise fall short. As the pressure to demonstrate credible, verifiable carbon removal increases, the role of consistent, open access EO data in support of environmental monitoring and reporting continues to grow.
