However, it has been under pressure for some time and in the future faces multiple threats that not only seriously endanger its future health but also the future of humanity itself.
Some 550 experts from 86 countries have spent nearly five years compiling a 1,600-page assessment detailing the challenges facing the ocean. This scientific guide offers the knowledge humanity needs to protect and sustain the planet.
It’s called the Global Ocean Assessment and this is what those 1,600 pages reveal.
The ocean is important to everyone, everywhere
- The ocean determines the daily lives of all people, even if they do not live in coastal areas.
- It stabilizes the climate by absorbing most of the planet’s excess heat, as well as harmful greenhouse gases. Without its cooling effect, more extreme weather conditions can be expected that will threaten food systems, supply chains and insurance markets.
- Serves as a food supply. When fish stocks collapse or supply chains break due to climate impacts or illegal fishing, prices rise, not only for seafood, but for many foods that depend on global trade and coastal economies.
- It provides physical and mental health benefits, medications and a significant proportion of breathable oxygen.
- The ocean supports trillions of dollars in global trade, tourism and jobs.
The ocean is under increasing stress
Humans are reshaping marine ecosystems. The world’s population reached 8.2 billion in 2024, and 37 percent of them lived within 100 kilometers of the coast.
Inevitably, this has concentrated human and economic activity in vulnerable coastal areas, increasing natural resource extraction, infrastructure expansion, waste discharge and habitat degradation.
At the same time, marine development is intensifying, with wind farms, deepwater oil infrastructure, and expanding cables and pipelines on the seafloor disrupting habitats further offshore.
Climate change is transforming conditions
The data related to ocean warming and sea level rise is dramatic.
- The rate of sea level rise, due to melting polar ice caps and temperature-driven water expansion, has doubled from up to 1.9 mm/year before 2015 to 4.3 mm/year in 2023.
- Arctic temperatures are rising four times faster than the global average.
- Hypoxic (or dead) zones, where oxygen levels are so low that most marine life cannot survive, now span 4.5 million km².
- 16 percent of the total ocean temperature increase since 1955 occurred after 2018.
Antarctic cormorant.
Biodiversity is declining in almost all marine habitats
Marine life is under severe stress, reflected in the decline of approximately 80 percent of Caribbean coral reefs since the 1970s. Ninety percent of the world’s coral reefs could disappear if warming exceeds 1.5°C above industrial levels.
Critical coastal ecosystems, such as mangroves and seagrasses, continue to decline.
Species from plankton to marine mammals are moving toward the north and south poles as temperatures rise, while non-native species are spreading more easily under altered environmental conditions.
Pollution is widespread and increasing
Marine pollution is intensifying.
Each year, 52 million tonnes of plastic waste enters the ocean, contributing to approximately 24 trillion microplastic particles, which are now known to affect more than 4,000 marine species.
Chemical pollution is also increasing: more than 4,000 pharmaceutical and personal care compounds have been detected in marine waters.
The good news? Some legacy pollutants, such as mercury, have decreased in some regions.
Ocean food systems are threatened
Marine food systems are a vital source of nutrition and livelihoods, providing 20 percent of the animal protein consumed by humans worldwide.
A school of striped mackerel feeds on ocean plastic.
Marine aquaculture continues to expand and has become a $90 billion global industry. Additionally, 121 million people engage in recreational marine fishing, contributing to local economies and well-being.
However, the stability of these systems is increasingly at risk:
- 37 percent of fish stocks were overfished in 2021.
- Illegal, unreported and unregulated fishing extracts between 8 and 14 million tons per year, generating between 9,000 and 17,000 million dollars in illicit income.
- Disease outbreaks, pollution and climate stress continue to challenge the long-term sustainability of marine aquaculture and fisheries.
The ocean economy is big but not yet sustainable
The ocean economy is valued at $1.5 trillion a year and is projected to exceed $3 trillion by 2030.
Coastal and marine tourism generates 174 million jobs.
Rising sea levels are threatening the tourism industry in places like Saint Lucia in the Caribbean.
Efforts are underway to understand the current impacts and sustainability of offshore oil and gas production, as well as shipping that carries more than 80 percent of global trade and contributes to global greenhouse gas emissions.
Governance and knowledge
International cooperation on ocean governance is gaining momentum, but the 57 global treaties related to ocean protection are resulting in a fragmented approach.
Achieving a sustainable ocean economy requires equity and the prominent inclusion of traditional knowledge and practices of indigenous communities. Without them, it will be more difficult to achieve healthy oceans, the well-being of communities and sustainable and equitable development.
Large gaps in ocean knowledge remain: only 27 percent of the seafloor will be mapped by 2025, leaving deep-sea ecosystems, biological processes and cumulative impacts poorly understood.
Solutions abound
Despite growing pressures, solutions exist, including nature-based approaches, emissions reductions and increased marine protection.
However, even full restoration of ocean ecosystems would contribute only about two percent of global climate mitigation goals, underscoring the need for systemic change.
The next decade is decisive: without rapid and coordinated global action, the health of the oceans will continue to deteriorate, threatening climate stability, biodiversity resilience, food security, livelihoods and well-being of billions of people.