Ocean State Report 4
Design and data visualisation work supporting the communication of the fourth Copernicus Marine Service Ocean State Report, translating complex ocean science, climate indicators and policy-relevant findings into accessible visual communication.
Ocean State Report 4
Communicating the State of the Ocean
The Ocean State Report 4 (OSR4) was the fourth edition of the Copernicus Marine Service Ocean State Report, providing a comprehensive assessment of the state, variability and ongoing changes in the global ocean and European regional seas.
The report brought together scientific observations, ocean models and analysis from more than 140 scientific experts across more than 30 European institutions. Its findings examined changes in the physical and biogeochemical ocean, climate-driven trends, extreme events and the value of ocean ecosystem services. :chatgpt-content-reference{index=“1”}
This project focused on the design and communication of complex ocean science and data, helping translate technical scientific information into visual and accessible material for wider audiences.
The Challenge
The ocean is one of the most important components of the Earth’s climate system, but communicating its condition is challenging.
Ocean science involves large and complex datasets covering:
- Sea level
- Sea surface temperature
- Ocean heat content
- Ocean currents
- Salinity
- Ocean colour
- Chlorophyll
- Primary production
- Carbon cycling
- Ocean acidification
- Deoxygenation
- Sea-ice extent
- Sea-ice volume
- Sea-ice thickness
- Extreme events
The Ocean State Report provides a way of bringing these datasets together to communicate a coherent picture of how the ocean is changing.
The communication challenge was therefore to make complex scientific evidence understandable without losing the underlying scientific meaning.
Copernicus Marine Service
The Copernicus Marine Service provides regular and systematic information on the physical and biogeochemical state of the global ocean and European regional seas.
It combines information from:
- Satellite observations
- In-situ observations
- Numerical ocean models
- Reanalyses
- Near-real-time analysis
- Forecasting systems
This creates a continuously updated picture of the ocean across space and time. :chatgpt-content-reference{index=“2”}
The service is implemented by Mercator Ocean International on behalf of the European Commission. :chatgpt-content-reference{index=“3”}
Ocean State Report
The Ocean State Report is designed to provide a regular, evidence-based assessment of the ocean.
It serves audiences including:
- The scientific community
- Policymakers
- International organisations
- Environmental stakeholders
- Economic stakeholders
- Educators
- The wider public
The report connects ocean observations and scientific analysis with the wider question of how society responds to a changing ocean.
Understanding a Changing Ocean
OSR4 focused particularly on the changes observed during the period leading up to 2018, while placing those observations within longer-term records.
The report highlighted a number of major indicators of ocean change.
Sea-Level Rise
Global mean sea level has continued to rise.
OSR4 reported an average rate of approximately:
3.3 ± 0.4 mm per year
since 1993.
The report also identified evidence that the rate of sea-level rise is accelerating. :chatgpt-content-reference{index=“4”}
Sea-level rise has implications for:
- Coastal communities
- Infrastructure
- Low-lying regions
- Coastal ecosystems
- Flood risk
- Adaptation planning
Ocean Warming
The ocean absorbs the vast majority of the excess heat associated with human-driven climate change.
OSR4 highlighted continuing warming of the global ocean and reported a global sea-surface temperature increase of approximately:
0.014 ± 0.001 °C per year
The report also noted that the four years preceding its assessment were the four warmest on record at that time. :chatgpt-content-reference{index=“5”}
Ocean warming affects:
- Marine ecosystems
- Fisheries
- Ocean circulation
- Sea level
- Marine heatwaves
- Climate feedbacks
- Coastal communities
Ocean Acidification
The ocean acts as a major sink for anthropogenic carbon dioxide.
While this uptake helps reduce the amount of excess CO₂ remaining in the atmosphere, it also changes ocean chemistry.
OSR4 highlighted the continuing acidification of the ocean and its potential consequences for marine organisms and ecosystems. :chatgpt-content-reference{index=“6”}
Ocean acidification is particularly important for organisms that depend on carbonate chemistry to build shells and skeletons.
Sea Ice
The report also examined changes in the polar ocean.
In the Arctic, the 2018 winter maximum sea-ice extent was the second lowest on record at the time, after 2017. :chatgpt-content-reference{index=“7”}
OSR4 also examined Antarctic and Baltic sea-ice conditions.
Sea ice is an important component of the ocean system because it influences:
- Ocean–atmosphere interactions
- Climate
- Ecosystems
- Ocean circulation
- Marine navigation
- Polar communities
The Blue, Green and White Ocean
A useful conceptual framework within OSR4 is the division of ocean indicators into three broad categories:
The Blue Ocean
The blue ocean describes the physical state of the ocean.
Indicators include:
- Sea-surface temperature
- Sea level
- Currents
- Waves
- Winds
- Ocean heat content
- Salinity
- Density
The Green Ocean
The green ocean describes the biogeochemical processes operating within the marine environment.
Indicators include:
- Chlorophyll-a
- Nutrients
- Primary production
- Carbon cycling
- Ocean acidification
- Deoxygenation
- Biological carbon pumps
The White Ocean
The white ocean describes the frozen components of the marine environment.
Indicators include:
- Sea-ice extent
- Sea-ice volume
- Sea-ice thickness
- Seasonal ice variability
Together, these three perspectives provide a more complete picture of the changing ocean.
Ocean Ecosystem Services
OSR4 went beyond describing physical and biogeochemical changes.
It also examined the services that ocean ecosystems provide to humanity.
Marine ecosystem services can be broadly grouped into:
- Provisioning services
- Regulating services
- Supporting services
- Cultural services
These services underpin economic activity, food systems, coastal communities and human wellbeing.
However, many of these benefits are not adequately represented in conventional economic accounting.
The Ocean as a Carbon Sink
One of the notable contributions of OSR4 was an assessment of the carbon-sink ecosystem service of the Mediterranean Sea.
The ocean absorbs a significant proportion of anthropogenic CO₂ emissions, making carbon sequestration an important ecosystem service.
For the Mediterranean Sea, OSR4 estimated the value of this carbon-sink service at approximately:
€2.1 billion in 2018
This provided an example of how scientific ocean observations can be connected with economic and policy analysis. :chatgpt-content-reference{index=“8”}
From Data to Decision-Making
A central purpose of the Copernicus Marine Service is not simply to collect ocean data.
The value lies in turning observations into information that can support decisions.
The pathway can be expressed as:
Observation → Data → Analysis → Indicator → Understanding → Decision
Ocean State Reports help bridge the gap between scientific monitoring and wider societal understanding.
This makes effective visual communication particularly important.
Data Visualisation
The project involved communicating scientific information where context and clarity are critical.
Effective data visualisation can help audiences understand:
- Long-term trends
- Spatial patterns
- Changes over time
- Relationships between indicators
- Regional differences
- Climate signals
- Environmental risks
- Socio-economic implications
The objective is not simply to make scientific data visually attractive.
It is to make the underlying evidence comprehensible, comparable and actionable.
Science Communication
Ocean State Report 4 sits at the intersection of:
Science + Data + Design + Policy
The underlying research is highly technical, but its implications extend well beyond the scientific community.
The report therefore needed communication approaches capable of working across multiple audiences.
For scientists, the evidence needs to remain accurate.
For policymakers, the implications need to be clear.
For industry and environmental stakeholders, the information needs to be relevant.
For the wider public, the story needs to be understandable.
Supporting Climate Policy
Ocean monitoring provides important evidence for understanding climate change and developing adaptation strategies.
Indicators such as sea-level rise, ocean warming, acidification and sea-ice loss can provide measurable evidence of changes occurring within the Earth system.
This information can support:
- Climate policy
- Marine protection
- Coastal adaptation
- Sustainable ocean management
- Maritime planning
- Environmental assessment
- Climate-risk analysis
The Ocean State Report therefore provides a bridge between operational Earth observation and policy-relevant evidence.
The Role of Copernicus
Copernicus demonstrates the value of combining multiple observing systems.
The marine service integrates:
Satellite observations + In-situ observations + Numerical models
This approach provides a much more complete understanding of the ocean than any individual observing system could provide.
Satellites provide extensive spatial coverage.
In-situ measurements provide direct observations within the ocean.
Models provide the ability to integrate observations and estimate ocean conditions across space and time.
Together, these systems create a powerful operational monitoring capability.
Project Context
Ocean State Report 4 was produced as part of the wider Copernicus Marine Service activity and subsequently published as a supplement to the Journal of Operational Oceanography.
The report represented a major collaborative scientific effort involving more than 140 experts from over 30 European institutions. :chatgpt-content-reference{index=“9”}
The OSR4 summary was released in 2020, with the report focusing on observations and analysis of the ocean’s state and changes, particularly during 2018. :chatgpt-content-reference{index=“10”}
Client
Mercator Ocean International
Mercator Ocean International implements the Copernicus Marine Service for the European Commission and develops operational ocean analysis and forecasting capabilities covering the global ocean and European regional seas. :chatgpt-content-reference{index=“11”}
Role
Design & Data
The project combined visual communication and scientific data to help communicate the findings and wider significance of the Ocean State Report.
The work required translating complex scientific material into accessible visual narratives while maintaining the credibility and context required for science and policy audiences.
Key Themes
The project brought together several areas of expertise:
- Data visualisation
- Information design
- Scientific communication
- Oceanography
- Climate science
- Earth observation
- Science policy
- Environmental communication
- Data storytelling
Impact
The Ocean State Report provides an important mechanism for communicating the condition of the global ocean and European regional seas.
By combining scientific evidence with effective communication, the project helps make complex ocean information more accessible to the people and organisations that need it.
The broader value lies in connecting:
Ocean observations → Scientific understanding → Public awareness → Policy and action
Selected Findings
| Indicator | OSR4 finding |
|---|---|
| Global mean sea level | ~3.3 ± 0.4 mm/year rise since 1993 |
| Sea-level acceleration | ~0.12 ± 0.073 mm/year² |
| Global sea-surface temperature | ~0.014 ± 0.001 °C/year increase |
| Arctic sea ice | 2018 winter maximum was second lowest on record at the time |
| Ocean carbon uptake | Ocean absorbs a major proportion of anthropogenic CO₂ |
| Mediterranean carbon-sink service | Estimated value of ~€2.1 billion in 2018 |
Figures and findings above are taken from the official OSR4 summary and press material. :chatgpt-content-reference{index=“12”}
Video
The project is represented in the accompanying video:
Ocean State Report 4 — Project Video