Oceans play a vital role in the health of the global ecosystem and the future of humanity. However, they have long been under severe pressure and face numerous threats that jeopardize their future well-being.
Approximately 550 experts from 86 countries dedicated nearly five years to compile a 1,600-page assessment detailing the challenges facing the oceans. This scientific report provides crucial information for protecting and sustaining the planet. Titled the World Ocean Assessment, its findings carry significant weight.
Oceans Matter to Everyone
- Oceans shape the daily lives of even those who do not live in coastal areas.
- They stabilize the climate by absorbing most of the planet’s excess heat and greenhouse gases. Without the ocean’s cooling effect, more extreme weather events would be expected, threatening food systems, supply chains, and insurance markets.
- Oceans provide food security. If fish stocks collapse or supply chains are disrupted due to climate impacts or illegal fishing, the prices of not only seafood but also many other foods dependent on global trade and coastal economies will rise.
- Oceans provide mental health and physical benefits, medicines, and a significant portion of the oxygen we breathe.
- Oceans support trillions of dollars in global trade, tourism, and employment.
Oceans Under Intense Pressure
Human activities are reshaping marine ecosystems. The global population reached 8.2 billion in 2024, with 37% living within 100 km of the coast.
This concentration leads to intensified human and economic activities in vulnerable coastal areas, increased extraction of natural resources, infrastructure expansion, waste discharge, and habitat degradation.
Simultaneously, offshore development is intensifying, with wind farms, deep-sea oil infrastructure, and expanding subsea cables and pipelines altering habitats further from the coast.
Climate Change is Transforming Conditions
Data on ocean warming and sea-level rise are stark.
- The rate of sea-level rise, driven by melting glaciers and thermal expansion of water, has increased from 1.9 mm/year before 2015 to 4.3 mm/year in 2023.
- Temperatures in the Arctic are rising four times faster than the global average.
- Hypoxic (dead) zones, where oxygen levels are too low for most marine life to survive, now cover 4.5 million km².
- Of the total increase in ocean temperatures since 1955, 16% occurred after 2018.
Biodiversity is Declining in Almost All Marine Habitats
Marine life is under severe pressure; coral reefs in the Caribbean have seen an approximately 80% decline since the 1970s. If warming exceeds 1.5°C above industrial levels, 90% of global coral reefs could be lost.
Critical coastal ecosystems like mangroves and seagrasses continue to shrink.
Species from plankton to marine mammals are shifting towards the poles as temperatures rise, while non-native species spread more easily under changing environmental conditions.
Pollution is Widespread and Increasing
Marine pollution is intensifying.
An estimated 52 million tons of plastic waste enter the ocean annually, contributing to an estimated 24 trillion microplastic particles that affect over 4,000 marine species.
Chemical pollution is also rising, with over 4,000 pharmaceutical and personal care compounds detected in seawater. The good news is that some legacy pollutants (e.g., mercury) have decreased in several regions.
Ocean Food Systems Are Under Threat
Marine food systems are a vital source of nutrition and livelihoods, providing 20% of the animal protein consumed by humans.
Aquaculture has become a $90 billion global industry, and recreational fishing engages 121 million people, contributing to local economies and well-being.
However, the stability of these systems is increasingly at risk:
- In 2021, 37% of fish stocks were overfished.
- Illegal, unreported, and unregulated (IUU) fishing removes an estimated 8-14 million tons of catch annually, generating $9-17 billion in illicit revenue.
- Disease outbreaks, pollution, and climate stress continue to challenge the long-term sustainability of aquaculture and fisheries.
Ocean Economy is Large but Not Yet Sustainable
The ocean economy is valued at $1.5 trillion annually and is expected to exceed $3 trillion by 2030.
Coastal and marine tourism provides employment for 174 million people.
The ongoing impacts and sustainability of offshore oil and gas production, and the shipping sector—which transports over 80% of global trade and contributes to global greenhouse gas emissions—are still being understood.
Governance and Knowledge
International cooperation on ocean governance is gaining momentum, but 57 global agreements related to ocean protection lead to a fragmented approach.
Achieving a sustainable ocean economy requires the equitable and prominent inclusion of indigenous peoples’ knowledge and traditional practices. Without these, ocean health, community well-being, and sustainable, fair development will be harder to attain.
As of 2025, only 27% of the seabed has been mapped, indicating significant gaps in ocean knowledge with insufficient understanding of deep-sea ecosystems, biological processes, and cumulative impacts.
Solutions Exist
Despite increasing pressures, solutions such as nature-based approaches, emission reductions, and expanded marine protected areas are available.
However, even the full restoration of ocean ecosystems would only contribute about 2% to global climate mitigation goals, highlighting the need for systemic change.
The next decade is decisive: without rapid, coordinated global action, ocean health will continue to decline, threatening climate stability, biodiversity resilience, food security, livelihoods, and the well-being of billions of people.
