Copernicus Marine Ocean State Report 5 Summary

05 Issue 5, 2021

OCEAN STATE REPORT SUMMARY

Implemented by

ABOUT THE OCEAN STATE REPORT The Ocean State Report is an annual publication of the Copernicus Marine Service that provides a comprehensive, state-of-the-art, scientific report on the current conditions, natural variations, and ongoing changes in the global ocean and European regional seas. It is meant to act as a reference for the scientific community, national and international bodies, decision-makers, blue economy actors, and the general public.

Using satellite data, in situ measurements, and models, the Copernicus Marine Ocean State Report provides a four-dimensional view (latitude, longitude, depth, and time) of the Blue, Green, and White Ocean. It draws on expert analysis, written by over 150 scientific experts from more than 30 European institutions. Scientific integrity is assured through a process of independent peer review in collaboration with the Journal of Operational Oceanography.

BLUE OCEAN

GREEN OCEAN

WHITE OCEAN

The Blue Ocean describes the physical state of the ocean, including for example sea surface temperature, sea level, ocean currents, waves, and sea winds as well as ocean heat content, salinity, and density.

The Green Ocean describes the biological and biogeochemical state of the ocean, including for example chlorophyll-a concentrations and nutrients as well as ocean acidification and deoxygenation.

The White Ocean refers to the lifecycle of floating ice within the polar regions, with indicators including the extent, volume, and thickness of sea ice in the Baltic Sea, Arctic Ocean, and Antarctic Ocean.

ABOUT THIS SUMMARY UNDERSTANDING THE IMPORTANCE OF MONITORING A COMPLEX OCEAN AND CRITICAL CHANGES OF MARINE ECOSYSTEMS.

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OCEAN STATE REPORT SUMMARY

This document is a summary of the fifth issue of the Copernicus Marine Ocean State Report, highlighting the current state and ongoing changes in the European regional seas and the global ocean. Drawing also from the Copernicus Marine Ocean Monitoring Indicators, this summary is approached from several angles, presenting the state of the changing ocean, examining evolving impacts of the changing ocean in line with climate change on environmental, human, social, and economic systems, and discussing the importance of science, data and services for ocean governance in adapting to these impacts. Lastly, it presents an overview of new tools developed using Copernicus Marine Service products and how accurate and timely information is key to monitoring, understanding, and adapting to the evolving ocean.

ISSUE 5

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PAGE 08-15

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A CHANGING OCEAN THE OCEAN IS UNDERGOING CONTINUOUS AND UNPRECEDENTED CHANGES AND KEY INDICATORS ARE BEING USED TO TRACK AND MONITOR THE OCEAN. This section explores the importance of the ocean, introducing the ocean indicators developed and provided by the Copernicus Marine Service for tracking the physical and biological changes already in motion across ocean environments over past decades.

THE IMPACTS OF A CHANGING OCEAN THE OCEAN IS FACING UNPRECEDENTED AND EVOLVING CHANGES AS A RESULT OF GLOBAL WARMING AND OTHER HUMAN-INDUCED PRESSURES - SUCH AS POLLUTION AND OVEREXPLOITATION - WHICH INTERFERE WITH NATURAL VARIATIONS, AND HAVE NUMEROUS IMPACTS ON HUMAN AND ENVIRONMENTAL SYSTEMS. This section provides an overview of the major impacts resulting from a changing ocean through a detailed discussion of recent observations and model data across the Blue, Green, and White Ocean.

MANAGING A CHANGING OCEAN: OCEAN GOVERNANCE DUE TO THE COMPLEXITY OF THE OCEAN, INTERNATIONAL OCEAN MANAGEMENT INFORMED BY SCIENCE AND DATA IS ESSENTIAL FOR SUSTAINABLE OCEAN STEWARDSHIP. This section describes the necessity of integrated, knowledge-based ocean governance systems and details the contributions the Copernicus Marine Service makes to marine monitoring and forecasting, which is necessary for ocean management.

MONITORING A CHANGING OCEAN: NEW TOOLS AND TECHNOLOGIES THE COPERNICUS MARINE SERVICE PROVIDES STATE-OF-THE-ART ANALYSES, OBSERVATIONS, AND FORECASTS TO ENHANCE UNDERSTANDING AND ANTICIPATE CHANGES IN THE OCEAN. This section discusses the new technologies and services developed using Copernicus observational data for improved ocean monitoring and forecasting, and recent examples of applying these tools in practice.

ISSUE 5

IMPACTS ABOUT OF CHANGING THIS SUMMARY OCEAN

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01.

A CHANGING OCEAN

AS THE OCEAN IS CHANGING DUE TO GLOBAL WARMING, OTHER HUMAN-INDUCED PRESSURES AND NATURAL VARIATIONS, IT IS CRUCIAL TO TRACK THESE CHANGES TO UNDERSTAND AND MEASURE HOW OCEAN ENVIRONMENTS ARE EVOLVING.

The global ocean is an interconnected body of water covering 71% of the Earth’s surface. It regulates the Earth’s climate and is the primary resource for sustaining life, both marine and on land. Either directly or indirectly, all life including humans, animals, and vegetation depends on the ocean for their sustenance, food, and well-being.

However, anthropogenic climate change has already contributed about 1.1°C 1 to global warming leading to many consequences and changes that are affecting the ocean and its coasts. Monitoring the ocean through a series of ocean indicators allows scientists and decision-makers to assess and respond to these environmental changes.

IN THIS SECTION

OCEAN INDICATORS WMO

GLOBAL CLIMATE INDICATORS The World Meteorological Organization (WMO) Global Climate Indicators are a set of parameters that provide key information for the most relevant domains of climate change.

Temperature and Energy

Ocean and Water

Cryosphere

KEY CHANGES AND HIGHLIGHTS

An ocean indicator is a simple, easy-to-understand method used to describe, measure, and monitor a complex ocean phenomenon, for example, sea level rise or sea ice decline. These indicators may change globally to locally, at different times, and can be used for ocean literacy and to build sustainable ocean observations for comprehensive scientific assessment and ocean stewardship2.

Split across the Blue, Green, and White Ocean, the Copernicus Marine Service Ocean Indicators provide continuous and regular reports on the state, variations, and changes of the global ocean and European regional seas.

Through recent observations, notable changes to the ocean include, for example, decreases in Arctic sea ice, rises in sea level, and increases in seawater temperature and acidity. These changes are linked to and exacerbated by the effects of climate change on ocean environments. Specific recent changes, their impacts, and new monitoring tools are further detailed in the accompanying ocean indicators and map, divided into the Blue, Green, and White Ocean.

IPCC, 2021: Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [MassonDelmotte, V., P. Zhai, A. Pirani, S. L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M. I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J. B. R. Matthews, T. K. Maycock, T. Waterfield, O. Yelekçi, R. Yu and B. Zhou (eds.)]. Cambridge University Press. In Press.

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2 Definition from the publication ‘Ocean science, data, and services for the UN 2030 Sustainable Development Goals’ by Schuckmann et al., 2020: https://www.sciencedirect.com/science/article/pii/S0308597X20302050

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OCEAN STATE REPORT SUMMARY

ISSUE 5

OCEAN INDICATORS BLUE OCEAN

GREEN OCEAN

SEA SURFACE TEMPERATURE

UNITS: °C/year Mediterranean Sea

+0.037

Baltic Sea

+0.036

Western Pacific Islands

+0.019

UNITS: pH units/year

-0.0016

+0.017 +0.071

Central Pacific Islands

+0.014 ± 0.020 °C/year

Black Sea

Global Ocean

+0.015

-0.16

Temperature and Energy

WHY IS IT IMPORTANT? Sea surface temperature plays a critical role in regulating the Earth’s climate, affecting the link between the ocean and the atmosphere, dynamic ocean structures, and currents as well as, for example, ocean fronts or exchanges between coasts and the open ocean, and the evolution of severe weather events.

+0.85

TREND FROM 1997-2019

+1.7

North Atlantic Ocean

TREND FROM 1997-2019

+0.17

± 0.83 mm/year

Iberian Biscay Ireland Seas

Central Pacific Islands

TREND FROM 1997-2018

−0.80

± 0.82 mm/year

Western Pacific Islands

±1.01 %/YEAR

Arctic Ocean

+0.71

TREND FROM 1997-2019

±0.16 %/YEAR

Western Pacific Islands TREND FROM 1997-2018

−0.82

+3.4

TREND FROM 1997-2018

−0.70 ±0.001 %/YEAR

OCEAN HEAT CONTENT 0-2000m

± 0.9 mm/year

Global Ocean

Temperature and Energy Continuous contributions to WMO State of the Climate

UNITS: watts/m2

TREND FROM 2005-2019

+1.0

Temperature and Energy

± 0.2 watts/m2

Continuous contributions to WMO State of the Climate

+ 30 000 +0.81 % ± 60 000 km2/decade

per decade

WINTER ( SEPTEMBER)

+ 110 000 +0.60% ± 60 000 km2/decade

per decade

Cryosphere * Antarctic trends not statistically significant

WHY IS IT IMPORTANT? Sea ice extent and thickness is diminishing at unprecedented rates, particularly in the Arctic, which can impact the global climate. Continued Arctic sea ice loss would lead, for example, to further regional warming, erosion of Arctic coastlines, and changes in global weather patterns.

THERMOSTERIC SEA LEVEL 0-2000m UNITS: mm/year

TREND FROM 2005-2019

+1.3 ± 0.2 mm/year

WHY IS IT IMPORTANT?

WHY IS IT IMPORTANT?

WHY IS IT IMPORTANT?

Ocean warming and melting land ice has caused sea level to rise at a rate of 3.1 mm/year on global average and is currently accelerating and exacerbating, for example, flooding in low-lying areas, damage to coastal infrastructure, and disruptions to coastal marine environments.

The ocean absorbs nearly 90% of excess heat from human activities leading to ocean warming. Ocean warming has major consequences, causing for example increased stratification, alteration of ocean currents, sea level rise, reduced solubility of carbon in ocean water, impacts on marine ecosystems, and many impacts in the Earth’s cryosphere.

ISSUE 5

SUMMER (FEBRUARY)

Pacific Islands Total Area

Chlorophyll-a is a pigment produced by many organisms for realising photosynthesis. Ocean surface chlorophyll is measured by satellites and is a proxy for ocean productivity.

Pacific Islands Total Area

per decade

±0.01 %/YEAR

WHY IS IT IMPORTANT?

± 0.9 mm/year

± 0.9 mm/year

± 0.4 mm/year

−1.33

±0.002 %/YEAR

+4.2

± 0.83 mm/year

+3.1

TREND FROM 1997-2019

±0.01 %/YEAR

+3.6

± 50 000 km2/decade

Black Sea

±0.68 %/YEAR

THE ANTARCTIC

+ 80 000 +0.67 %

UNITS: %/YEAR

Black Sea

± 0.84 mm/year

+3.5

per decade

ANNUAL AVERAGE

CHLOROPHYLL-A

±0.87 %/YEAR

± 0.83 mm/year

Central Pacific Islands

- 400 000 -2.60 %

WHY IS IT IMPORTANT?

Baltic Sea

TREND FROM JANUARY 1993MAY 2020

UNITS: mm/year

+2.9

per decade

WINTER (MARCH)

± 30 000 km2/decade

Roughly 50% of Earth’s oxygen production takes place in the ocean, sustaining marine life cycles from the seashore to the greatest depths of the ocean. However, human activities (e.g. climate change, eutrophication) have contributed to ocean deoxygenation in the open and coastal ocean, with consequences on marine life.

+0.21

SEA LEVEL

North West Shelf

- 840 000 -12.89 %

Cryosphere

TREND FROM 1997-2019

+4.5

SUMMER (SEPTEMBER)

± 0.018 mol/m /year

Mediterranean Sea

Baltic Sea

per decade

2

±0.001 °C/year

+2.5

TREND FROM 1955-2019

UNITS: mol/m2/year

± 0.006 °C/year

ANNUAL AVERAGE

± 60 000 km2/decade

OXYGEN INVENTORY

+0.016

THE ARCTIC

± 2 000 km2/decade

The absorption of anthropogenic carbon in the ocean helps to mitigate the effects of climate change, but also leads to a reduction in seawater pH, which today represents nearly a 30% increase in acidity - also called ocean acidification. Ocean acidification poses a threat to ocean environments, particularly to marine life.

± 0.004 °C/year

TREND FROM 1979-2020

-520 000 -4.46 %

WHY IS IT IMPORTANT?

Pacific Islands Total Area

Mediterranean Sea

Contributions to: Eurostat/EEA in support of SDG 14

As pH decreases, ocean acidification increases

Black Sea

± 0.007 °C/year

Ocean and Water

±0.0006 pH units/year

± 0.001 °C/year

UNITS: km2/decade

TREND FROM 1985-2019

Global Ocean

North West Shelf

± 0.004 °C/year

SEA ICE EXTENT

OCEAN ACIDIFICATION

TREND FROM 1993-2019

± 0.003 °C/year

WHITE OCEAN

As ocean waters warm from continued uptake of anthropogenic heat, seawater expands (thermosteric effect) causing a rise in sea level. Thermosteric sea level rise contributes to roughly 30-40% of global mean sea level rise threatening coastal and marine environments.

A CHANGING OCEAN

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KEY CHANGES AND HIGLIGHTS This map provides a summary of the key highlights detailed throughout the report, including recent ocean changes, impacts, and new tools, each in relation to their geographical location.

CHANGES IN THE BLUE OCEAN ARCTIC OCEAN

CHANGES IN THE GREEN OCEAN

• Arctic Ocean warming estimated to contribute nearly 4% to global ocean warming • New “IcySea” forecast tool for sea ice drift monitoring and forecasts

CHANGES IN THE WHITE OCEAN

NORTH ATLANTIC • A new indicator used by EuroStat on eutrophication (SDG 14.1)

NORTH SEA • Extreme variability from cold-spells and marine heatwaves linked to changes in catches of sole, European lobster, sea bass, red mullet, and edible crabs

GLOBAL OCEAN

MEDITERRANEAN SEA • Ocean warming and salinity increases have intensified in the past decade • Higher-than-average wave heights (+2.5 m) in the southern Mediterranean in 2019 • Four consecutive record Acqua Alta events in Venice in November 2019 • Invasive lionfish migration into the Ionian Sea in 2019 • A new forecasting system for jellyfish watch • A new tool for extreme event monitoring and forecasting in Malta

• A new satellite-derived planktonto-fish index in support of ocean management and fisheries

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OCEAN STATE REPORT SUMMARY

ISSUE 5

FRAM STRAIT • Reduced sea ice transport through the Fram Strait and the Barents Sea

NORDIC SEAS

• Spring phytoplankton growth affected by nitrogen and surface silicate change

BALTIC SEA

• Unusual 2019 sea level and extreme wave conditions in the Gulf of Bothnia • Reduction of the nitrogen to phosphorus ratio from 1993-2017, particularly in the Baltic Proper, the Gulf of Finland, and the Gulf of Riga.

BARENTS SEA

• Nearly a 90% reduction in average sea ice thickness has led to a decrease in sea ice import from the polar basin • Unexpected near-normal sea ice conditions around the Svalbard archipelago and the Barents Sea in 2019

INDIAN OCEAN

• Development of additional attributes for Indian Ocean Dipole monitoring, which reported strong events in 1997 and 2019 linked to droughts and extreme precipitation

BLACK SEA

• Lower-than-average wave heights (up to -1.5 m) in 2019 • A new Benthic Hypoxia indicator (related to low oxygen levels) developed to support coastal management and marine protection

ISSUE 5

A CHANGING OCEAN

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02.

THE IMPACTS OF A CHANGING OCEAN

THE GLOBAL OCEAN IS A DYNAMIC, ACTIVE, AND VITAL ELEMENT OF THE EARTH SYSTEM; ONE THAT IS UNDERGOING SWIFT, STARK, AND UNPRECEDENTED CHANGES WITH MAJOR IMPACTS ON HUMAN WELL-BEING AND THE ENVIRONMENT.

The ocean responds to natural variations in the Earth system and faces pressures from climate change, anthropogenic pollution, and overexploitation.

Any change affecting the ocean can have significant environmental, social, and economic implications from a local to a global scale. This section highlights some of the major recent changes in the ocean and their impacts – including extreme high water levels, changing trends in water quality, response of marine species to ocean changes and extremes, and sea ice reduction.

IN THIS SECTION

CHANGING BLUE OCEAN

CHANGING WHITE OCEAN

ACQUA ALTA IN VENICE

THE NORTHERN HEMISPHERE: THE ARCTIC

A combination of concurrent events - unusually high mean sea level, a high spring tide, and extreme local and regional weather conditions - caused an unprecedented series of exceptionally strong Acqua Alta events in Venice, flooding over 50% of the city between 11 and 18 November 2019.

Rapidly declining sea ice extent in the Arctic region set new record low levels and the transportation of older and thicker sea ice brought unexpected near-normal sea ice conditions to the Barents Sea.

CHANGING GREEN OCEAN

CHANGING GREEN OCEAN

FISH MIGRATION, INVASIVE SPECIES AND EXTREME TEMPERATURE EVENTS

EUTROPHICATION AND OLIGOTROPHICATION

Warming ocean waters have caused many marine species to move toward cooler waters, prompting the introduction of invasive species, and extreme temperature events have led to variations in fish populations and catches.

Nutrient pollution from land-based activities, such as farming and industry, deteriorates water quality and increases favourable conditions for eutrophication, whereas the reduction of ocean surface inorganic nutrient concentrations can be linked to oligotrophication. Both processes are impacting the functioning of the ecosystem.

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OCEAN STATE REPORT SUMMARY

ISSUE 5

CHANGING BLUE OCEAN

ACQUA ALTA IN VENICE

HIGHEST WATER LEVELS AND RECORD FLOODING SINCE 1966

WHAT ARE ACQUA ALTA EVENTS? Acqua Alta - which translates to ‘high water’ in Italian - are periods of exceptionally high water levels in Venice, occurring usually between autumn and spring, where levels rise to more than 80 cm above normal. These exceptionally high water events cause extensive flooding due to various favourable conditions such as high tides, strong weather, Sirocco wind conditions, and sea surges.

WHAT IS CHANGING?

Tide level (cm)

RECORD HIGH TIDE 4 NOV 1966

200

THE EVENTS OF 2019 Between 11 and 18 November, Venice suffered from four successive extreme water level events - something that has never occurred within one single week before. These successive exceptional events were caused by a series of factors, namely higher than average sea level in the northern Adriatic Sea due to unusually low atmospheric pressure, high spring tide, a local storm, and strong Sirocco winds which pushed seawater towards the Venice lagoon. The 12 November event saw water levels rise to 1.89m - the highest recorded level since 1966 - due to a combination of high sea level from atmospheric pressure, high spring tide, a local storm, and strong Sirocco winds. On 13 November, the water level rose to 1.45m due only to high sea level from atmospheric pressure and high spring tide. Water levels during the events on 15 and 17 November rose to 1.56m and 1.51m respectively due to a combination of high sea level from atmospheric pressure, high spring tide, and strong Sirocco winds.

IMPACTS

1.94 m

HIGH TIDE 12 NOV 2019

180

1.89 m

160 15 NOV 17 NOV 13 NOV

140

1.40 m

120 100 80

HEIGHT AT WHICH IT IS CONSIDERED AN EXCEPTIONAL EVENT

WALKING LEVEL AT PIAZZA SAN MARCO

HEIGHT AT WHICH THERE IS FLOODING OR ACQUA ALTA

0.80 m

60 40 20

Acqua Alta events have severe impacts on the city of Venice. For the extreme November events, Venice was left unprepared: water level for the 12 November event was underestimated by almost 0.4 m.

Following the results of the Copernicus Marine Ocean State Report, the use of higher resolution models in tandem with observations is recommended to improve the accuracy of future forecasts. While extreme events like Acqua Alta are naturally occurring, continued anthropogenic warming and other human-induced pressures are anticipated to exacerbate the impacts of future extreme events3.

0

ACQUA ALTA EVENTS 2019

Depiction of the 2019 Acqua Alta water levels in relation to an average human height. At 0.80 m, roughly walking level at the Piazza San Marco, flooding is considered an Acqua Alta. At 1.40 m, roughly knee-high, flooding is considered an exceptional event.

On 12 November, the water levels in Venice reached 1.89 m, around waist high, marking this event as a record extreme flooding event.

The water levels in Venice during the following Acqua Alta’s events on 13, 15, and 17 November reached heights of 1.45 m, 1.56 m, and 1.51 m respectively.

KEY TAKEAWAYS • • •

Acqua Alta events are events of high water which cause widespread flooding in Venice In 2019, Venice saw a series of four successive, unprecedented and unusually strong Acqua Alta events with the highest recorded levels since 1966.

Underestimated forecasts left Venice unprepared for the 2019 extreme events, prompting the use of higher resolution models and observations to improve forecast accuracy.

3 IPCC, 2019: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate [H.-O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.)]. In press.

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THE IMPACTS OF A CHANGING OCEAN

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CHANGING GREEN OCEAN

EUTROPHICATION AND OLIGOTROPHICATION

NEW INDICATOR FOR EUTROPHIC AND OLIGOTROPHIC STATES WHAT IS EUTROPHICATION?

WHAT IS OLIGOTROPHICATION?

Eutrophication occurs when water is excessively rich in nutrients, primarily phosphorus and nitrogen, which fosters damaging levels of algae growth. Eutrophication only happens if waters are eutrophic for multiple consecutive years (i.e. a trend over time).

Oligotrophication is the opposite of eutrophication. It occurs when waters are extremely low in nutrients and therefore cannot support much aquatic plant growth. Similar to eutrophication, oligotrophication only happens if waters are oligotrophic for multiple consecutive years (i.e. a trend over time).

WHAT IS CHANGING?

WHAT IS CHANGING?

The increase of nutrients (nitrogen, phosphorus) from human activities, including urban, agriculture, industry, and fossil fuel combustion, are primary sources exacerbating eutrophication. Land-based run-off from these activities introduce excess nutrients to marine ecosystems and boost harmful plant growth especially in coastal areas.

IMPACTS Notably in Europe, eutrophication is a long-lasting water quality problem. Increased plant growth can lead to decreases in dissolved oxygen levels in seawater and, if dense enough, can block natural sunlight (shadow effect), potentially causing devastating effects on coastal environments and marine biodiversity.

In 2019, extensive coastal and shelf waters in the northern Atlantic, notably the Iberian Shelf waters, North Sea, Celtic Sea, and Irish Sea, showed active flags for oligotrophication.

12.7% of all observations were shown to be in an oligotrophic state, stemming from strong decreases in chlorophyll concentrations and uneven distributions of algal bloom periods.

IMPACTS In the open ocean, oligotrophic areas are often called ‘ocean deserts’4. Oligotrophication can lead to a decrease in the size and abundance of higher organisms and less sinking material to support life on the sea floor.

OCEAN EUTROPHICATION

Increase of nutrients causing eutrophication (nitrogen, phosphorus) from human activities (urban, industry, agriculture, fossil fuel combustion).

Run-off of nutrients via air, surface water, or groundwater into the ocean

Shadow effect: Blocked sunlight can inhibit photosynthesis, disrupting life below Seagrass meadows

Water Quality Species Displacement Biodiversity

Organic matter falls through the water column and decomposes O2 depleted area

Sathyendranath et al., (2018), Section 2.5: Oligotrophic gyres, in Copernicus Marine Service Ocean State Report, Issue 2, Journal of Operational Oceanography, 11:sup1, S1-S142, DOI: 10.1080/1755876X.2018.1489208

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OCEAN STATE REPORT SUMMARY

ISSUE 5

O2 decrease from excessive oxygen consumption due to algae decomposition

Suffocation and mortality or escape of animals

Photo: Copernicus Sentinel data (2019), processed by ESA, CC BY-SA 3.0 IGO

MONITORING EUTROPHICATION AND OLIGOTROPHICATION A NEW INDICATOR: Using satellite observations of chlorophyll-a concentrations, compared with climatology data over the past 20 years, a new indicator was developed to measure annual mean percentages for both eutrophic and oligotrophic waters. Since waters can only be considered eutrophic or oligotrophic if these conditions are sustained over several years, this new method provides the baseline for continuous monitoring to identify increasing or decreasing trends in these states over time.

WHY WAS IT SPECIALLY DEVELOPED? This indicator was developed out of a political need to safeguard marine ecosystems from continuing anthropogenic threats and climate change. While there are many ways to measure eutrophication, this indicator supports the European Marine Strategy Framework Directive (MSFD), Eurostat, and the United Nations Sustainable Development Goal 14 – specifically target 14.1 – which aims to significantly reduce marine pollution, particularly from land-based activities, by 2025.

WHAT DID WE OBSERVE?: • The 2019 eutrophic and oligotrophic indicator map (left) showed minimal positive eutrophic areas (red) but indicated that more than 25% of chlorophyll-a observations in the North Atlantic and 50% in the Mediterranean Sea, Black Sea, and Baltic Sea are above normal for the 1993-2017 reference period.

In comparison, oligotrophic flags (blue) were more positive, existing mostly along coastal areas.

• These flags do not denote confirmed eutrophication or oligotrophication but identify the regions that require close observation to determine if these trends are sustained over time as even small fluctuations can have long-term impacts.

The 2019 annual eutrophic and oligotrophic indicator map for the north Atlantic calculated using the Copernicus Marine Ocean Colour dataset. Active eutrophic flags (red) indicate that more than 25% of valid observations were above normal climatological level (1998-2017). Active oligotrophic flags indicate that more than 25% of valid observations were below normal.

KEY TAKEAWAYS • • •

Eutrophication and oligotrophication are long-term water quality issues which affect the stability of marine ecosystems.

The new indicator method makes it possible to continously monitor changes in ocean eutrophication and oligotrophication trends over time, supporting directives aimed at significantly reducing marine pollution.

Few ocean regions showed levels of eutrophic conditions in 2019, while primarily coastal waters showed signals of oligotrophic conditions.

ISSUE 5

THE IMPACTS OF A CHANGING OCEAN

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CHANGING GREEN OCEAN

FISH MIGRATION, INVASIVE SPECIES, AND EXTREME TEMPERATURE EVENTS OCEAN WARMING IS AFFECTING FISH DISTRIBUTION AND CATCHES WHAT IS CHANGING? Fish and other oceanic organisms are vulnerable to changes in ocean temperature. As temperatures increase, many marine species are migrating to cooler waters, impacting key fish stocks and the stability of marine ecosystems.

OCE CHA

OCEAN WARMING

The rise in ocean temperature is one of the major drivers for migration of marine species to higher latitudes. More subtropical and tropical marine species are replacing temperate water fish, reshaping fisheries and catch compositions.

MOST MARINE SPECIES ARE MOVING DEEPER AND TOWARDS THE POLES

WARM WATER SPECIES ARE SPREADING TO NEW AREAS AND BECOMING INVASIVE WHAT WE OBSERVED

LOSS IN ABUNDANCE AND DISTRIBUTION OF SPECIES THAT CAN’T MIGRATE

SPECIES MIGRATE TOWARDS COLDER WATERS

LATITUDE

OCEAN WARMING

INVASIVE LIONFISH IN THE IONIAN SEA: A significant increase in the temperature of the eastern Mediterranean Sea in 2019 contributed to a northern spread of invasive lionfish, Pterois miles, through the Suez Canal – an invasive migration that had relatively abated in 2018.

40 36

GREATER DEPTH

34 MEDITERRANEAN SEA INCREASE IN ABUNDANCE AND DISTRIBUTION OF MIGRATED SPECIES

SUEZ CANAL

32 2019 1991-2018

30

16

18

20

22

24

28

30

32

34

36

LONGITUDE HIGHER LATITUDES

IMPACTS

Invasive lionfish sightings in the eastern Mediterranean for 1991-2018 are plotted with grey circles, whereas lionfish sightings of the following year (2019) are highlighted in green illustrating the introduction of lionfish further into the Mediterranean and the Ionian Sea.

As a result of climate change, ocean warming is one of the major factors affecting marine species, through migration, causing changing conditions for fisheries with societal and economic implications. The migration of hundreds of species moving to higher latitudes and greater depths with warming has been recorded. These shifts reassemble food webs and can have severe consequences5.

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Malin L. Pinsky et al., (2020). Climate-Driven Shifts in Marine Species Ranges: Scaling from Organisms to Communities. Annual Review of Marine Science. 12:1, 153-179

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OCEAN STATE REPORT SUMMARY

ISSUE 5

EAN ANGE

EXTREME TEMPERATURE EVENTS

Aggravated by global warming, extreme marine heatwaves and cold spells are affecting the growth and reproduction of marine organisms, causing sea-life decline when temperature limits are exceeded.

IMPACT OF MARINE HEAT WAVES AND COLD SPELLS ON CATCHES OF EXPLOITED SPECIES WHAT WE OBSERVED THE EFFECTS OF MARINE HEATWAVES AND COLD SPELLS IN THE NORTH SEA This issue of the Ocean State Report has analyzed the impact of marine heatwaves and cold spells on catch in the North Sea, with particular impact on five species, namely sea bass, sole, European lobster, edible crabs, and red mullet.

RED MULLET

SOLE

EUROPEAN LOBSTER

EDIBLE CRABS

SEA BASS

Catches of European lobster (above) were particularly impacted by observed marine heatwaves in the North Sea

KEY TAKEAWAYS • • •

In 2019, a northward spread of invasive lionfish, Pterois miles, was observed through the Suez Canal Invasive species like the lionfish can be linked to ocean warming as these species favour warmer waters Marine heatwaves and cold spells have varying impacts on the growth, reproduction, and behaviour of specific marine species, impacting their populations as well as their catches

ISSUE 5

THE IMPACTS OF A CHANGING OCEAN

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CHANGINGWHITE WHITEOCEAN OCEAN CHANGING

THE NORTHERN HEMISPHERE: THE ARCTIC A CHANGING ICE LANDSCAPE: SEA ICE EXTENT WELL BELOW AVERAGE AND RAPIDLY DECLINING

THE ARCTIC

SEA ICE EXTENT

The swift and steady decline of sea ice extent is a serious challenge facing the Arctic. The map, below centre, details the average sea ice extent from September 1993 to September 2014 (light green with opacity) compared with the sea ice extent from September 2020 (blue with opacity), showing the severe decline of sea ice in recent years.

SEPTEMBER AVERAGE

1993 - 2014

SEPTEMBER AVERAGE

2020

WHAT IS CHANGING? Arctic sea ice has shown a steady decline in extent and thickness over the last thirty years. Summer (September) sea ice has followed a decreasing trend of -12.89% per decade (trend from 1979-2020), with record lows of sea ice extent in the last two years.

150°W

SEA ICE EXTENT (million km2)

SEA ICE EXTENT 120°W

16 14 12 10 8

2020 1979-2020

6

DE CE M BE R

NO VE M BE R

OC TO BE R

SE PT EM BE R

AU GU ST

JU LY

JU NE

M AY

AP RI L

M AR CH

FE BR UA RY

JA NU AR Y

4

90°W

Sea ice extent in the Arctic estimated from daily values during the 1979-2020 reference period (red curve) compared with the estimated sea ice extent in 2020 (green curve).

KEY VALUES

- 2.13 MILLION KM

2

60°W

6X GERMANY

LOSS OF SEA ICE EXTENT BETWEEN 1979 AND 2020

This is equivalent to losing an area of sea ice about 6 times the size of Germany.

IMPACTS

30°W

Sea ice loss in the Arctic can have a lasting impact on the cold branch of the global thermohaline circulation. This global circulation helps drive and regulate climate. Today, the Arctic is warming at a faster pace than the entire globe, which is known as Arctic amplification. This warming has caused older and thicker sea ice to become thinner and more mobile. The unpredictable behaviour of sea ice characteristics presents challenges to shipping, fishing, tourism, and local communities in Arctic regions6.

FISHERIES

SHIPPING

TOURISM

6 IPCC, 2019: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate [H.-O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.)]. In press.

14

OCEAN STATE REPORT SUMMARY

ISSUE 5

BARENTS SEA WHAT IS CHANGING? UNEXPECTED AND NEAR-NORMAL SEA ICE CONDITIONS IN 2019 During summer and autumn 2019, the Arctic Ocean experienced a record low sea ice extent, following the long-term negative trend since the late 1970s.

Despite this overall decreasing trend in the Arctic, parts of the northern Atlantic, in the Barents Sea near Svalbard, saw unprecedented near-normal sea ice conditions in 2019 close to the climatological average (1981-2010).

The transportation of older and thicker Arctic sea ice combined with strong northern winds resulted in exceptionally large sea ice inflows, strengthening ocean freshwater levels and decreasing ocean heat content.

IN AUGUST 2019

180°

STRONG NORTHERN WINDS

ARCTIC REGION

HIGH TRANSPORT OF OLD THICK ICE FROM THE ARCTIC

150°E SVALBARD

INCREASED FRESH WATER STRENGTHENING OF OCEAN STRATIFICATION

120°E

BARENTS SEA

OCEAN WARMING NORWAY

The mobility of older and thicker sea ice, encouraged by strong northern winds, brought increased sea ice inflows to the Barents Sea in 2019. These conditions saw a return to near-normal sea ice extent in this area, increasing freshwater content, strengthening the stratification of ocean layers, and preventing ocean warming from below.

SEA ICE EXTENT IN THE BARENTS SEA

0.6 0.4 0.2

2012 2018

• •

DE CE M BE R

NO VE M BE R

OC TO BE R

SE PT EM BE R

AU GU ST

JU LY

JU NE

Sea ice extent in the Barents Sea depicting the estimated daily values from 2012 (black), 2018 (red), 2019 (blue), and the median sea ice extent during the 1981-2010 reference period in dark and light grey shading.

The chart shows an average decrease in sea ice extent in 2012 and in 2018, much lower than the median level, but a sharp increase in 2019, almost in line with the median sea ice reference.

0°

•

M AY

JA NU AR Y

30°E

AP RI L

2019

0.0

M AR CH

60°E

0.8

FE BR UA RY

SEA ICE EXTENT (million km2)

90°E

KEY TAKEAWAYS

Sea ice extent in the Arctic is rapidly declining at a rate of -12.89% (summer trend 1979-2020), with record lows in the last two years.

Sea ice inflows in the Artic region play a key role in regulating Arctic climate.

Changes in sea ice conditions have significant impacts on marine ecosystems, weather, and socio-economic activities including tourism, fishery, and shipping.

ISSUE 5

THE IMPACTS OF A CHANGING OCEAN

15

03.

MANAGING A CHANGING OCEAN: OCEAN GOVERNANCE

SCIENTIFICALLY-SOUND KNOWLEDGE IS ESSENTIAL FOR SUPPORTING TRANSFORMATIVE OCEAN GOVERNANCE BY EMBRACING THE ROLE OF THE OCEAN AS A MULTIDIMENSIONAL AND INTERCONNECTED ELEMENT FOR A SUSTAINABLE FUTURE.

The three pillars of sustainable development - environment, society, and economy - depend upon the health, services, and vitality of the ocean. However, climate change, pollution, and overexploitation have placed unprecedented pressures on the ocean, requiring the urgent need for sustainable measures for governance, adaptation, and management in order to secure the various life support roles the ocean offers for human well-being.

Scientifically-sound knowledge derived from high-quality ocean products and delivered by ocean services is critical to stimulate transformative change in ocean governance. Considering the ocean as a fundamental factor in the Earth system and embracing the multidimensional and interconnected nature of the ocean is the bedrock for a sustainable future.

WHAT IS OCEAN GOVERNANCE?: According to the IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC), ocean governance is associated with deciding, implementing, and monitoring policies linked to ocean changes, providing guidance for negotiation, interest mediation, and the sharing of rights and responsibilities for the use and exploitation of ocean resources. International ocean governance particularly refers to the areas that exist beyond the territorial waters of individual countries, and that are beyond the jurisdiction of any one government. Under ocean governance, institutional and organisational arrangements are established, modified, and refined in support of the mitigation of conflicts and the realisation of mutual gains among ocean governance actors. Such actors include institutions as well as administrative, state, indigenous, or traditional and international governance structures7.

Lead by example

Drive international negotiations

RESILIENT

Develop capacity and financimg

CLEAN AND HEALTHY

AIMING FOR AN OCEAN THAT IS...

UNDERSTOOD

Initiate & support innovative governance

PRODUCTIVE

Strengthen/ build partnerships & alliances

Support innovation and knowledge production

Figure source: EU international ocean governance (iog) forum recommendations, https://3rd-iogforum.fresh-thoughts.eu/wp-content/uploads/ sites/89/2021/04/iog-recommendations-2021web.pdf

The International Ocean Governance (IOG) Forum set up by the European Commission identified priority areas and the Copernicus Marine Service actively contributes to support this strategy with marine observations for improving investment in blue science and for building key international research partnerships under a knowledge-based governance strategy.

7 IPCC, 2019: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate [H.-O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.)]. In press.

16

OCEAN STATE REPORT SUMMARY

ISSUE 5

FROM OCEAN DATA TO OCEAN GOVERNANCE Ocean products from observations and models provide the foundation for the development of scientifically-sound ocean knowledge for monitoring and reporting on the state, variability, and change of the ocean. Ocean governance is reliant on ocean knowledge and cutting-edge blue science in order to enable governance actors in guiding negotiations, mediating interests, and sharing rights and responsibilities to establish regulations, management and implementation for sustainable ocean stewardship.

SUSTAINABLE OCEAN STEWARDSHIP

SUSTAINABLE OCEAN STEWARDSHIP:

At the top, ocean data and scientifically-sound knowledge help various actors and decision-makers understand the function and changes of the ocean and take stock of the health, services, and vitality of the ocean to develop appropriate measures for sustainable ocean stewardship.

OCEAN GOVERNANCE AGREEMENTS & CONVENTIONS

RIGHTS & RESPONSIBILITIES

REGULATIONS, MANAGMENT, IMPLEMENTATION

OCEAN GOVERNANCE ACTORS OCEAN KNOWLEDGE:

KNOWLEDGE TRANSFER

REPORTING

INDICATORS

Ocean data and knowledge allow for understanding, describing and monitoring the current state, variability, and change s in the ocean. Ocean related reports such as the Copernicus Marine Service Ocean State Report, the Intergovernmental Panel on Climate Change (IPCC) Special Report on Ocean and Cryosphere, or the UN World Ocean Assessment are critical gateways to acquire, assess, and transfer ocean knowledge.

ASSESSMENTS

OCEAN KNOWLEGDE OCEAN SCIENCE PRODUCTS

OCEAN SERVICES

MODEL, FORECAST & REANALYSIS

OCEAN DATA AND PRODUCTS:

OCEAN MONITORING REASEARCH & DEVELOPMENT IN SITU OBSERVATIONS

SATELLITE OBSERVATIONS

COORDINATION & COLLABORATION

OCEAN OBSERVATIONS

8

The Global Ocean Observing System8 encompasses a wide range of in situ and remote sensing measurement techniques provided through national and international co-operations.

Through careful coordination, integrity, and durability, this system delivers the essential information necessary for sustainable development, safety, and well-being.

The Global Ocean Observing System (2021) https://www.goosocean.org/

THE NEW PHASE OF THE COPERNICUS MARINE SERVICE The Copernicus Marine Service uses satellites, in situ platforms, and models to describe and forecast the state of the ocean.

Improvements in the Blue, Green, and White Ocean monitoring capabilities from Copernicus 1 to Copernicus 2 support ocean governance. This provides a foundation for the development of downstream, fit-for-purpose applications for marine safety, marine biodiversity protection, sustainable management of ocean resources, climate assessments, and more.

HOW DOES THE COPERNICUS MARINE SERVICE MONITOR THE OCEAN? Satellite Observations

Models

COPERNICUS 1 (2015-2021)

Under Copernicus 1, the Copernicus Marine Service provides a fully operational ocean monitoring and forecasting service encompassing expert analysis, user support and training resources. Notable improvements include evolving from a Blue Ocean focus to increasing offers for the Green and White Ocean, longer time series and forecasts, higher spatial and temporal resolution, and improved scientific quality service-wide, alongside many additional marine monitoring parameters including waves, acidity, and icebergs.

Knowledge and Expertise

Digital Representation of the Ocean

In-Situ Observations

COPERNICUS 2 (2021-2027)

Under Copernicus 2, the Copernicus Marine Service remains a global reference through a commitment to cutting-edge science and user-driven feedback and services. With a focus on expanding data sources and strengthening coastal, marine biology, and Arctic offers, providing first-in-class digital tools is a top priority. These tools include providing high performance access to data and computational resources; harnessing artificial intelligence and machine learning to improve the service catalogue; and ultimately evolving the already underway digital twin of the ocean vision.

ISSUE 5

FOR MORE INFORMATION For further information see the Mercator Ocean Journal Issue 57, focused on the Copernicus Marine Service (2015-2021) achievements, and the associated brochure.

MANAGING A CHANGING OCEAN: OCEAN GOVERNANCE

17

04.

MONITORING A CHANGING OCEAN: NEW TOOLS AND TECHNOLOGIES

THE COPERNICUS MARINE SERVICE PROVIDES CONTINUOUS OCEAN OBSERVATION AND MODEL DATA FOR THE DEVELOPMENT OF TOOLS AND TECHNOLOGIES TO MONITOR OCEAN CHANGES AND TRENDS.

18

OCEAN STATE REPORT SUMMARY

The ocean products and services that the Copernicus Marine Service provides are used by other systems to develop state-of-the-art tools for tracking and forecasting key ocean changes. These tools and technologies, including alert systems, forecasting technologies, and real-time monitoring programs, help to protect marine environments and human communities, to provide early warning systems, to safeguard economic infrastructure, and to plan for and manage extreme ocean events. The Ocean State Report provides insight into the design and functioning of three of these downstream tools, with each benefitting either the Blue, Green, or White Ocean.

ISSUE 5

MONITORING BLUE OCEAN

MONITORING GREEN OCEAN

MONITORING WHITE OCEAN

SUPPORTING LOCAL MANAGEMENT IN MALTA

PREDICTING JELLYFISH BLOOMS IN THE NORTHWESTERN MEDITERRANEAN

RECEIVING TAILORED SEA ICE INFORMATION

WHY IS IT IMPORTANT?

WHY IS IT IMPORTANT?

WHY IS IT IMPORTANT?

The ocean plays a leading role in influencing climate and weather. Monitoring extreme ocean and weather conditions at the local level is essential to mitigate risks, loss and damage to key infrastructure assets, and to increase early warning and safety during harsh sea and weather conditions.

Jellyfish blooms are naturally occurring and/ or anthropogenically-induced outbursts of populations in a specific time and location.

These blooms can be harmful to humans and can cause coastal area closures and socioeconomic losses particularly for the tourism sector, as seen in the 2018 outbreak of the Portuguese Man-of-War.

Due to a decline in sea ice, growing maritime activities are taking place in Arctic regions that also lack reliable internet connection. There is a need for sea ice products that can be easily downloaded and interpreted in these regions, even with low-bandwidth connections.

HOW CAN THE NEW TOOL HELP?

HOW CAN THE NEW TOOL HELP?

HOW CAN THE NEW TOOL HELP?

This new Maltese forecasting tool provides alerts and near-real-time evolution of potentially extreme ocean and weather conditions. Used in the Maltese Islands in 2019, this multi-model approach assists local authorities in improving land and marine protection, providing guidance for safe ocean navigation, and relaying key information to emergency units for use during extreme event conditions.

HOW DOES IT WORK AND WHAT HAVE WE LEARNED?

In situ measurements, 3D numerical models, and remotely sensed observations from Copernicus satellites were used to predict, monitor, and verify the ocean and meteorological conditions of two storms hitting the Maltese Islands in 2019. The results showed a promising potential of providing future reliable and real-time ocean and weather information.

This new jellyfish tracking system helps to identify the location and population dynamics of jellyfish blooms and minimise associated socio-economic losses by predicting future blooms, tracking known blooms, and providing early warnings to coastal regions.

HOW DOES IT WORK AND WHAT HAVE WE LEARNED?

This tool uses observational data and jellyfish sightings from 2005-2008 as a basis for 3D models which detail the spread of jellyfish colonies. These models account for ocean currents and winds to forecast where known colonies might migrate. Initial model outputs provided a reliable forecast of the 2018 event in the western Mediterranean.

OBSERVED

Designed to work offline and to be downloadable under low-bandwidth conditions, the “IcySea” application tool uses Copernicus Marine data to provide near-real-time monitoring and calibrated forecasts for the speed and direction of sea ice drifts to help assess how fast sea ice conditions are changing.

HOW DOES IT WORK AND WHAT HAVE WE LEARNED? Sea ice drift forecasts are produced using machine learning and observational data from Copernicus satellites to produce 10-day point trajectories revealing sea ice movement. Built upon end-user feedback over the last five years and delivered in a user-friendly interface, this tool has helped improve operational planning and safety for transport and navigation. a)

NEW TOOL OUTPUT

Multiple marine fields, encompassing nearshore, coastal, and open sea areas (depicted by the individual boxes), are used to provide a multi-area and versatile early warning alert system for the Maltese Islands in the event of severe weather and ocean conditions.

ISSUE 5

Locations of Portuguese Man-of-War (Physalia physalis) colony sightings in the western Mediterranean Sea during April 2018.

b)

Illustration of the IcySea service. a) Sea ice drift trajectories for the ice drift forecast: the dark red color indicates the initial sea ice condition, and the light red color indicates the trajectory forecast. The black box indicates the area zoom shown in b), visualising a Sentinel-1 radar image of the sea ice structure.

MONITORING A CHANGING OCEAN: NEW TOOLS AND TECHNOLOGIES

19

Implemented by

ABOUT THE COPERNICUS MARINE SERVICE

ABOUT MERCATOR OCEAN INTERNATIONAL

The Copernicus Marine Service provides a large catalogue of ocean products, ocean indicators, reports, and analyses alongside special training, educational and business support services for ocean observation, tracking and monitoring.

It is funded by the European Commission and is implemented by Mercator Ocean International, a centre for global ocean analysis and forecasting.

Mercator Ocean International was selected by the European Commission (EC) to implement the Copernicus Marine Service in 2014.

Based in France, it is a non-profit organization providing oceanographic products and information that cover the global ocean. Its scientific experts design, develop, operate, and maintain state-of-the-art numerical modelling systems that describe and analyse the past, present, and near-future state of the ocean in 4D (reanalyses, hindcasts, near-real-time data, and forecasts). It has also been selected by the EC as one of three implementers of the Copernicus WEkEO DIAS cloud computing platform for Earth observation data. The organisation also pilots EU4OceanObs, a project meant to strengthen the EU’s prominence and influence in international ocean governance for an enhanced global ocean observation system (EC Service for Foreign Policy Instruments).

The Copernicus Marine Service supplies regular and systematic reference information on the state of the physical and biogeochemical ocean at the global and European regional scale. It provides key input that supports major EU and international policies and initiatives, and can contribute to combating pollution, marine protection, maritime safety and routing, sustainable use of ocean resources, developing marine energy resources, blue growth, monitoring changes caused by human activities, and more. It also aims to increase awareness amongst the general public by providing European and global citizens with information about ocean-related issues.

JOIN THE COPERNICUS MARINE SERVICE COMMUNITY Webportal of Mercator Ocean International mercator-ocean.fr/en/

Mercator Ocean @MercatorOcean

Webportal of Copernicus Marine Service marine.copernicus.eu

MercatorOcean

Service desk email servicedesk.cmems@mercator-ocean.eu Collaborative forum forum.marine.copernicus.eu

Mercator Ocean mercator-ocean

Copernicus Marine Service @CMEMS_EU

Copernicus Marine Service Copernicus Marine Service

Copernicus Marine Service Copernicus Marine Service

CONTACT Karina von Schuckmann Mercator Ocean International karina.von.schuckmann@mercator-ocean.fr Gratianne Quade Mercator Ocean International gratianne.quade@mercator-ocean.fr

Full Ocean State Report will be available at: https://www.tandfonline.com/toc/tjoo20/current Citation: von Schuckmann, K., P.-Y. Le Traon, N. Smith, A. Pascual, S. Djavidnia, J.-P. Gattuso, M. Grégoire, G. Nolan (2021): Copernicus Marine Service Ocean State Report, Issue 5, Journal of Operational Oceanography, DOI: 10.1080/1755876X.2021.194624 Disclaimer: This summary is written in collaboration with both scientists and communication professionals and it is intended to provide some context and basic scientific explanation surrounding the key findings of the Ocean State Report and the Ocean Monitoring Indicators.

Acknowledgement : Special thanks to the entire author team of the 5th installment of the Copernicus Marine Service Ocean State Report for their dedication and expertise. We would particularly like to thank the reviewers of this summary (in alphabetical order): Gilles Garric, Phillippe Gaspar, Jean-Pierre Gattuso, Marilaure Gregoire, Elodie Gutknecht, Audrey Hasson, Shelia Heymans, Paula Kellet, Pierre-Yves Le Traon, Alexandre Mignot, Coralie Perruche, Shuba Sathyendranath, and Neville Smith.

The Ocean State Report is a supplement of the Journal of Operational Oceanography (JOO), an official Publication of the Institute of Marine Engineering, Science & Technology (IMarEST), published by Taylor & Francis Group.

In accordance with the terms of the Creative Commons Attribution-Non-Commercial-No-Derivatives License, this summary properly cites and does not alter nor transform the original work.

Design and production: Design & Data - www.designdata.de Cover photo: contains modified Copernicus Sentinel data (2019), processed by ESA, CC BY-SA 3.0 IGO / recolored by Design & Data

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