UNESCO has released the State of Ocean Report. According to it, the ongoing efforts to solve ocean crises at the global level and to validate new technologies aimed at removing carbon dioxide from the atmosphere are still insufficient. Oceans play an important role in regulating the climate.The purpose of the Ocean State Report is to inform policymakers about the state of the ocean and encourage research and policy actions towards ‘the ocean we need for our desired future’, thereby contributing to the 2030 Agenda and especially SDG 14 as well as other global processes (such as UNFCCC, Biodiversity Convention and Sendai Framework for Disaster Risk Reduction).
Key findings of the Ocean State Report
- Increase in ocean surface heat: From 1960 to 2023, the upper 2,000 meters of the oceans have warmed at a rate of 0.32 ± 0.03 watts per square meter (W/m2). It is expected to continue warming in the future, leading to irreversible changes.
- Scientists are particularly concerned about the rapid increase in ocean temperatures over the past two decades, where the rate has doubled to 0.66 ± 0.10 W/m2.
- The years 2021 to 2030 have been declared as the United Nations Decade of Ocean Science for Sustainable Development.
- Sea level rise: Sea levels will continue to rise in 2023. From 1993 to 2023, the global average sea level has risen at a rate of 3.4 +/- 0.3 mm/year.
- Acidification: The open ocean is experiencing a steady decline in pH (or increase in acidity), with the average decline in global surface ocean pH per decade since the late 1980s being 0.017-0.027 pH units.
Causes of Ocean Degradation
- Earth Energy Imbalance (EEI): Another consequence of the increase in greenhouse gas emissions from human activities is the increase in Earth Energy Imbalance (EEI) by the oceans. EEI is the balance between the energy coming from the sun and the energy being emitted from the Earth.About 90% of the EEI is being absorbed by the oceans, resulting in a cumulative increase in ocean heat content (OHC) in the upper 2,000 meters of the water column. OHC is the total amount of heat stored by the oceans.
- Deoxygenation: Scientists believe that the increase in ocean heat content (OHC) prevents mixing of ocean layers, thereby reducing the pre-decomposed oxygen content of near-surface high latitude water reaching the deeper layers of the oceans. This reduction is called ‘deoxygenation’.This reduction could have long-term negative impacts on coastal and larger marine ecosystems, a sustainable blue economy, and coastal communities that depend on the oceans for tourism, fisheries, aquaculture, and ecosystem services.
- Acidification: According to the report, another threat is the average global increase in ocean acidification across all ocean basins and seas. Coastal waters are acidifying due to natural processes such as freshwater inflow and biological activity, as well as climate patterns such as temperature change and the El Niño/Southern Oscillation (ENSO).
- Chemical composition: Human activities such as nutrients from agricultural and industrial activities also affect the chemical composition of coastal areas. Since 2020, there has been growing interest in marine carbon dioxide removal (MCDR) technology using a wide range of methods, raising a number of technical, environmental, political, legal, and regulatory challenges.The United States and the European Union have announced significant funding for research for MCDR in 2023.
Suggestions for the future
- There is a need to improve space-based and real-world observation systems to monitor sea level rise at global, regional and coastal levels.
- Marine carbon dioxide removal involves technologies that capture carbon dioxide from the air and store it permanently. If used in a balanced manner, it can prove to be effective.
- Existing coverage needs to be increased. Observation time series from all regions are not sufficient to determine trends and data gaps. However, by the year 2024, there will be 638 stations recording ocean pH levels.
- Longer-term data sets are needed for coastal areas than for the open ocean due to natural variability. This can help determine the time of emergence of ocean acidification trends.
- The report emphasizes the need to provide regular data on the pattern of ocean warming and its impacts. This is essential to address the current challenge for healthy and resilient oceans.
- According to UNESCO’s State of the Ocean Report-2024, there is a lack of adequate and integrated data due to a lack of observation and research.
- It is necessary to focus on techniques that change the chemical composition of seawater so that the oceans can absorb more carbon dioxide from the atmosphere and conserve nutrients such as iron to encourage the growth of microscopic plankton. These nutrients can sink to the sea floor and remain stored for centuries or longer.
- Mangrove forests, seagrass meadows and aquatic life should be promoted to enhance carbon storage in the coastal ocean.