NEWS – UNESCO’s State of Ocean Report Highlights Knowledge Gaps

HIGHLIGHTS

Key Role of Oceans in Climate Regulation

• Oceans are critical in climate regulation.
• Current understanding is insufficient to address multiple ocean crises.
• Need for validation of new technologies for carbon dioxide removal.

Insufficient Data and Research

• Observations and research are falling short.
• Lack of adequate and aggregated data noted by Vidar Helgesen, executive secretary of the Intergovernmental Oceanographic Commission of UNESCO.

Oceanic Warming Trends

• Upper 2,000 meters of oceans warmed at 0.32 ± 0.03 W/m2 from 1960-2023.
• Accelerated warming in the past two decades at 0.66 ± 0.10 W/m2.
• Regular data needed to monitor ocean warming and its impacts.

Increased Earth Energy Imbalance (EEI)

• Human activities increase EEI uptake by oceans.
• About 90% of EEI absorbed by oceans, increasing Ocean Heat Content (OHC).
• Increased OHC causes deoxygenation, affecting coastal and marine ecosystems.

Deoxygenation Concerns

• Decreased oxygen in ocean layers due to less mixing.
• Long-term negative impacts on coastal ecosystems and economies.
• Unclear if deoxygenation is accelerating with increased OHC.

Ocean Acidification

• Global increase in ocean acidification observed.
• Continuous pH decline of 0.017-0.027 units per decade since the late 1980s.
• Data primarily from a limited set of long-term observations.

Coastal Waters and Acidification

• Coastal waters affected by natural processes and human activities.
• More extended data sets needed to determine acidification trends in coastal areas.

Rising Sea Levels

• Global mean sea level rose at 3.4 ± 0.3 mm/year from 1993 to 2023.
• Need to improve observing systems for sea level monitoring at various scales.

Marine Carbon Dioxide Removal (mCDR) Technologies

• Recent developments in mCDR technologies noted.
• Techniques include altering seawater chemistry and adding nutrients to encourage plankton growth.
• Increased interest in mCDR since 2020 due to scientific papers and funding.

Challenges and Unknowns in mCDR

• Technical, environmental, political, legal, and regulatory challenges.
• Unknowns include the potential impact on the ocean carbon cycle and unintended consequences.

Coastal Blue Carbon Habitats

• Interest in restoring or expanding coastal blue carbon habitats.
• Effectiveness of these habitats in sequestering carbon remains uncertain.