Copernicus Climate Change Service (C3S)

The Copernicus Climate Change Service (C3S) is a flagship initiative of the European Union’s Copernicus Programme, designed to provide authoritative information about the past, present, and future state of the Earth’s climate. Managed by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the European Commission, C3S delivers comprehensive climate data, analyses, and projections to support policy-making, scientific research, and climate adaptation planning. It plays a central role in advancing Europe’s response to climate change through data-driven understanding and decision support.

Background and Establishment

The Copernicus Programme, the European Union’s Earth observation programme, was launched to create an integrated system for monitoring environmental and climatic conditions using satellite and in situ data. Building on earlier research projects, the Copernicus Climate Change Service (C3S) was formally established in 2014 as one of six thematic services of Copernicus, alongside those for atmosphere, land, marine, security, and emergency management.
C3S succeeded the European Climate Assessment and Dataset (ECA&D) and other precursor initiatives that had been collecting and analysing climate data across Europe. Its establishment reflected growing political and societal recognition of the need for reliable, accessible, and science-based climate information to support the European Union’s commitments under international frameworks such as the Paris Agreement (2015) and the UN Framework Convention on Climate Change (UNFCCC).
Administered by ECMWF and headquartered in Reading, United Kingdom, C3S integrates satellite observations, ground-based measurements, and advanced modelling to provide climate intelligence for a broad range of users, from policymakers and researchers to businesses and the general public.

Objectives and Mandate

C3S operates under a mandate to empower society through climate knowledge. Its principal objectives include:

• Monitoring the Earth’s climate system through observations and reanalysis of historical data.
• Providing seasonal to long-term climate forecasts to support risk management and adaptation planning.
• Delivering consistent, quality-controlled datasets of essential climate variables (ECVs).
• Supporting climate change mitigation and adaptation policies at European and global scales.
• Ensuring open and free access to climate information for all users.

These goals align with the EU’s Green Deal, Climate Law, and sustainability objectives, ensuring that climate data supports both policy and innovation.

Data Sources and Methodology

C3S draws upon a combination of satellite, in situ, and reanalysis data, integrated through ECMWF’s advanced computational models. Its data sources include:

• Satellite Observations: ESA’s Sentinel missions, EUMETSAT’s MetOp satellites, and NASA’s Earth-observing missions contribute information on surface temperature, ocean heat, and atmospheric composition.
• Ground-based Networks: Meteorological stations, ocean buoys, and atmospheric monitoring systems provide direct measurements of climate parameters.
• Reanalysis Systems: The ERA5 reanalysis, one of C3S’s cornerstone products, reconstructs the global climate from 1950 to the present using a data assimilation system that merges observations with model output.
• Climate Models: Regional and global climate simulations from the Coupled Model Intercomparison Project (CMIP) are used for projections under different emission scenarios.

This integrated methodology ensures consistency, spatial completeness, and temporal continuity in climate datasets, forming the foundation for scientific analysis and policy use.

Core Components and Services

C3S provides a wide portfolio of operational services and datasets, structured into several key components:

• Climate Data Store (CDS): The central online platform for accessing C3S datasets, including reanalyses, satellite observations, and climate projections. It allows users to visualise, download, and process climate data.
• ERA5 Reanalysis: A global dataset offering hourly estimates of atmospheric, land, and oceanic parameters from 1950 onwards, widely used for research, policy, and commercial applications.
• Sectoral Information System (SIS): Provides tailored climate indicators and impact assessments for specific sectors such as agriculture, energy, water management, tourism, and health.
• Seasonal Forecasts: Combines multiple model systems to provide forecasts up to six months ahead, supporting early warning and preparedness efforts.
• Climate Indicators and Reports: Annual publications, such as the European State of the Climate (ESOTC) report, summarise climate trends, anomalies, and extreme events.

These components collectively deliver a comprehensive and operational climate information system accessible to all users.

Applications and Use Cases

C3S data and tools are applied across multiple domains, facilitating informed decision-making and adaptation to climate change. Key applications include:

• Policy Support: Provides data for the EU Climate Law, Paris Agreement reporting, and the UN Sustainable Development Goals (SDGs), particularly SDG 13 (Climate Action).
• Disaster Preparedness: Enables risk assessment and early warning for heatwaves, droughts, floods, and storms through seasonal forecasting.
• Energy and Agriculture: Helps optimise renewable energy production forecasts (solar and wind) and supports climate-resilient agricultural planning.
• Urban Planning: Supplies information for climate adaptation in urban areas, including temperature trends, flood risk, and heat island effects.
• Scientific Research: Supports global and regional climate studies through validated long-term datasets.
• Private Sector Innovation: Businesses use C3S data for insurance modelling, supply chain risk assessment, and sustainability reporting.

Through these diverse applications, C3S fosters a data-driven approach to managing climate risks and promoting resilience.

Relationship with Other Copernicus Services

C3S works in close coordination with other Copernicus services to ensure an integrated environmental monitoring system. It complements the Copernicus Atmosphere Monitoring Service (CAMS) by providing long-term climate context for atmospheric data. Collaboration with the Copernicus Emergency Management Service (CEMS) supports climate-informed disaster management, while synergy with the Copernicus Marine Environment Monitoring Service (CMEMS) enhances ocean–atmosphere interaction studies.
Together, these services form a comprehensive Earth observation infrastructure, supporting the EU’s overarching environmental and climate governance framework.

Scientific and Technical Partnerships

C3S is underpinned by a broad network of European and international partnerships. It collaborates with:

• European Space Agency (ESA) for satellite data acquisition.
• EUMETSAT for meteorological data streams.
• National Meteorological Services across Europe.
• Academic and research institutions, including the Joint Research Centre (JRC), to ensure scientific excellence.
• International Organisations such as the World Meteorological Organization (WMO) and the Intergovernmental Panel on Climate Change (IPCC) for harmonisation of methodologies and data exchange.

These partnerships ensure that C3S products meet the highest standards of scientific reliability and operational accuracy.

Challenges and Limitations

Despite its success, C3S faces several operational and scientific challenges:

• Data Volume and Processing: Managing petabytes of climate data requires continuous investment in high-performance computing and storage infrastructure.
• Uncertainty in Projections: Long-term climate models, though robust, are subject to uncertainties in emission pathways and natural variability.
• User Accessibility: Translating complex datasets into easily interpretable information for non-specialist users remains an ongoing challenge.
• Global Integration: Ensuring coherence between European and global datasets requires harmonised standards and methodologies.

C3S continuously addresses these challenges through technological innovation, stakeholder engagement, and methodological refinement.

Impact and Global Relevance

The Copernicus Climate Change Service has become a global reference for operational climate information, recognised for its transparency, scientific quality, and open-access approach. It underpins the European Union’s leadership in climate action by providing the evidence base for mitigation, adaptation, and resilience strategies.
C3S contributes significantly to global climate governance by supporting national adaptation plans (NAPs), Nationally Determined Contributions (NDCs), and UNFCCC reporting. The ERA5 dataset, in particular, is widely used by researchers, journalists, and policymakers worldwide to assess climate variability and extremes.
Through its Climate Data Store and Sectoral Information System, C3S democratises access to climate data, enabling communities, industries, and governments to make informed decisions grounded in scientific evidence.

Future Outlook

As climate challenges intensify, C3S continues to evolve to meet growing societal and scientific demands. The next phase, under the Copernicus 2.0 initiative, will feature enhanced spatial and temporal resolution of observations, integration of new satellite missions (including Sentinel-4 and Sentinel-5), and expanded services for adaptation and risk management.