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UNESCO State of the Ocean Report
Context:
UNESCO’s State of the Ocean Report emphasizes significant knowledge gaps in research and data regarding the alarming rise in ocean temperatures.
More on News:
- The UNESCO State of the Ocean Report offers insights on ocean-related scientific activities and analyses describing the current and future state of the ocean.
- As per the report, observations and research are falling short and hence there is a lack of adequate and aggregated data on ocean warming.
- The report calls for the need to provide regular data on how ocean warming is evolving and its impacts to support the decade’s challenge for healthy and resilient oceans.
More about the report:
- The ocean warming rate of the upper 2,000 metres (m) has doubled to 0.66 watt per square metre(W/m2) in the last two decades from 0.32 W/m2 in 1960.
- Increased greenhouse gas
emissions from human activities increase Earth energy imbalance (EEI) uptake by oceans.
- EEI is the balance between incoming energy from the Sun and outgoing energy from the Earth.
- About 90 per cent of the EEI is being absorbed by oceans, resulting in a cumulative increase in ocean heat content (OHC) in the upper 2,000 m of the water column.
- OHC is the total amount of heat stored by oceans.
- Increased OHC prevents ocean layers from mixing, lowering the preformed oxygen content of near-surface high-latitude waters reaching the deeper layers of oceans and creating ‘deoxygenation’.
- Deoxygenation has long-term negative impacts on the health of coastal and large marine ecosystems, a sustainable blue economy, and coastal communities.
- Mean global increase in ocean acidification in all ocean basins and seas.
- The open ocean has been experiencing a continuous decline in pH (increase in acidic levels), with an average global surface ocean pH decline of 0.017-0.027 pH units per decade since the late 1980s.
- Sea levels continued to rise from 1993 to 2023 increasing at a rate of 3.4 +/-0.3 mm/yr.
- The UNESCO report provides an update on recent advancements in marine carbon dioxide removal (mCDR) technologies.
- This involves techniques that capture carbon dioxide from the air and store it durably.
- The potential of using mCDR to enhance the ocean carbon sink is still under observation.
About Ocean Warming:
- It refers to the increase in ocean temperatures due to the absorption of heat from the atmosphere.
- The ocean absorbs most of the excess heat from greenhouse gas emissions, leading to rising ocean temperatures.
- As per the Intergovernmental Panel on Climate Change (IPCC) Special Report on the Ocean and Cryosphere in a Changing Climate, the 0−700 m and 700–2000 m layers of the ocean have warmed at rates of 5.31 ± 0.48 and 4.02 ± 0.97 ZJ from 2005 to 2017.
Impact of Ocean warming:
- Leads to deoxygenation: Absorption of heat leads to a reduction in the amount of oxygen dissolved in the ocean coupled with ocean acidification (the decrease in pH of the ocean due to its uptake of CO2).
- By 2100 the total oxygen content of the ocean will likely have declined by 3.2-3.7% relative to 2000, if greenhouse gas emissions continue to rise as per IPCC 2019.
- Sea-level rise: Resulting from the thermal expansion of seawater and continental ice melting.
- As per the IPCC report, the Global sea level rise will rise between 0.61-1.10 m by 2100 if emissions continue to rise.
- Marine species and ecosystems: Marine fishes, seabirds and marine mammals all face very high risks from increasing temperatures, including high levels of mortalities, and loss of breeding grounds.
- Coral reefs are also affected by increasing temperatures which cause coral bleaching and increase their risk of mortality.
- After mass coral mortalities due to bleaching, reef recovery typically takes at least 10–15 years as per IPCC.
- Impact on humans: A report by the Food and Agriculture Organisation estimates that marine and freshwater capture fisheries and aquaculture provide 4.3 billion people with about 15% of their animal protein.
- Ocean warming is a serious risk to food security and people’s livelihoods globally.
- Impact on Weather: Rising ocean temperatures are linked to more frequent marine heatwaves, which can lead to extreme weather events such as intense hurricanes, heavier rainfall, and snowstorms.
- As per the study, if greenhouse gas emissions continue to rise, the Indian Ocean sea surface temperature may exceed 28°C.
- This creates a favourable environment for the development of tropical cyclones and extremely heavy rainfall events.
Intergovernmental Panel on Climate Change (IPCC):
- Created in 1988 by the World Meteorological Organisation (WMO) and the United Nations Environment Programme (UNEP).
- The IPCC is an organisation of governments that are members of the United Nations or WMO.
- Currently has 195 members.
- Objective:
- To provide governments at all levels with scientific information that they can use to develop climate policies.
- The IPCC provides regular assessments of the scientific basis of climate change, its impacts and future risks, and options for adaptation and mitigation.