Human beings are the most evolved species on our planet. Our ability to affect our environment, even without trying, has put a large strain on the natural order of things and has shifted the ecosystem in ways that seem impossible. One such adverse effect is ocean pollution.
The oceans cover more than 70% of Earth’s surface. But beneath its vast blue surface, a silent disaster is brewing that threatens marine life, food security and climate change. Ocean pollution is the contamination of marine ecosystems by plastics, chemicals, oil and waste products. Every year, over 11 million tonnes of plastic waste are dumped into the seas. Even astounding that his figure could triple to 29 million tonnes by 2040 if we do not take any action (UNEP,2023; WWF, 2022).
And this is a problem now, not for the future. The oceans were previously thought to be self-cleaning and so vast that it was impossible to choke. But now, under the immense pressure of the human population, signs of marine pollution and subsequent breakdown are showing. Massive floating garbage patches, dead coral reefs, toxic dead zones and micro-plastics in the food chain are indications that we should take this seriously.
More than 1000 marine species are affected by ocean plastic pollution. Over a million marine animals die from ingestion or entanglement (GreenMatch,2024). Microplastics have been found in 60% of marine fish and even in human blood and lungs. As marine biodiversity collapses at an alarming rate and plastics make their way into our food chain, the time for implementing proactive change is here. This blog takes a deep look at the causes of ocean pollution, the impact it has on the environment and what it will take to reverse the tide of marine plastic pollution before it's too late.
Ocean pollution means introducing harmful substances (pollutants) into the ocean, causing long-term damage to marine life. These can be solid waste like plastics, untreated chemical run-offs, oil spills, poisonous heavy metals like mercury and even noise. These pollutants render the once vibrant marine ecosystems into barren, lifeless ones.
Around 80% of marine pollution originates from land, is carried by rivers, drains and direct dumping into the oceans (UNESCO,2024). Ganges and Yangtze rivers are amongst the top sources of plastic waste in the ocean, bringing urban and industrial waste to the seabeds.
The major types of ocean pollution are:
Ocean Plastic Pollution: These are the most visible and abundant form of pollutants. Plastics remain for thousands of years and accumulate in the environment.
Chemical Run-off: Fertilisers and pesticides washed off from the fields via rain and industrial sewage dumped into the rivers cause massive deterioration of life on accumulation in the seas.
Oil Spills: Oil spills happen in offshore mining rigs and ship transports leakages. They have adverse effects on the sea birds.
Heavy Metals & Toxins: Mercury, lead and arsenic accumulate in the bodies of marine organisms and move up the food chain to humans.
Noise Pollution: Shipping, underwater drilling and other commercial maritime activities interfere with the lives of marine mammals.
Thermal Pollution: Waste heat from industrial plants raises the temperature and affects the species' behaviour and habitat balance.
In most cases, marine pollution is not localised but spread on a global scale as plastics and other pollutants ride the ocean currents. Oceans may seem limitless, but modern human activity has achieved a scale that can affect the oceans. Understanding the reasons for marine pollution is the first step to battling this planetary crisis.
You might have seen the image of plastics and nets around a turtle's neck, marine creatures mistaking plastic bags for jellyfish or vast carpets of waste floating on the oceans like islands. Marine plastic pollution is the most visible and widespread form of ocean pollution, affecting millions of marine creatures from the tropics to the Arctic. It is estimated that there are between 75 to 199 million tonnes of plastic already circulating in marine environments (OECD,2022).
The Great Pacific Garbage Patch presents one of the most alarming visuals of plastic accumulation. It’s a massive floating mass of debris estimated to be twice the size of Texas. It contains 1.8 trillion tonnes of plastic pieces. Most of these are microplastics, less than 5mm in size (The Ocean Cleanup,2023).
Land-based sources: ~ 80% of plastic waste in the ocean comes from littering, poor waste management and industrial run-offs.
Maritime activities: ~20% of ocean plastic pollution comes from maritime activities such as commercial fishing.
Once in the oceans, plastics can break down but cannot totally degrade. These small pieces, microplastics, have been found in fish, sea birds, marine mammals and humans as well. They absorb toxic chemicals and then enter our food chain, and eventually affect human health.
Plastic pollution is not only an ecological disaster but a socio-economic one as well. It affects fisheries, tourism, coastal livelihood and maritime navigation. Let’s take a look at how it affects marine life.
Beyond the aesthetic elements, marine pollution has real effects on the lives of marine creatures. From microscopic planktons to macro organisms such as fish, turtles and whales, oceanic life is being poisoned and entangled in our waste. Over 1 million marine animals, including 100,000 mammals and turtles, die due to plastic entanglement and ingestion (Condor Ferries, 2024)
The invisible microplastics often pose a greater risk when they are ingested by fish or other creatures, stunting their growth and reproduction. This is also an entry point of plastics in the food chain and it eventually ends up in human diets. Heavy metals, endocrine disrupters and pathogens carried in these then cause diseases and deformities.
A 2022 WWF report found that over 2100 marine species have been impacted by plastic pollution. 90% of seabirds have plastic in their stomach. Whales, turtles and other creatures mistake plastic for jellyfish and ingest them. Coral reefs have a higher risk of disease spreading from exposure to plastics. In one striking example, scientists found over 100 Kg of ocean plastic pollution debris in the stomach of a stranded sperm whale in Norway.
It doesn’t stop at an individual level. The damage is to whole populations and ecosystems. It disturbs predator-prey dynamics, reproduction rates and can even impact the migration patterns of marine animals like turtles and whales who rely on environmental cues that are disrupted by noise and pollution. The collapse of marine life is a global warning sign of worse things to come.
The world is witnessing a collapse in marine biodiversity due to ocean pollution. Ecosystems that have formed after millions of years of steady growth are quickly breaking down.
Marine species populations have declined by 49% since 1970.
Sharks, sting rays and apex predator populations have dropped by over 70% in the past 50 years (Nature,2021).
An estimated 84% of global coral reefs are experiencing bleaching due to warming oceans and pollution (NOAA, 2024).
Over two-thirds of the oceans are now considered to have been significantly altered by ocean pollution. (Our Shared Seas)
The data indicates that the problem is very real. It’s not a distant future prediction but a crisis affecting the world right now.
While plastics are the major pollutants, there are several other causes of ocean pollution.
Agricultural chemicals, fertilisers and untreated sewage can lead to eutrophication, an increase in algae growth in the water. When this algae dies, its decomposition uses up the dissolved oxygen in the water. This creates a dead zone in which very little life can survive.
Today, there are over 400 documented dead zones around the world. There is one spanning 6000 square miles in the Gulf of Mexico (UNEP,2021). Coastal waters around India have also shown similar patterns and have caused alarms amongst environmental watchers.
Oil spills can be devastating when they occur. Oil coats birds, suffocates fish and destroys coastal ecosystems such as mangrove forests that not only provide a base for a diverse ecosystem but also act as a natural bank against tides and storms.
Discarded fishing nets, traps, gears, etc, are also known as ‘ghost gears’. These account for a significant part of maritime pollution. These abandoned tools remain in the oceans and sea creatures such as turtles get entangled in them and often die. Turtles, dolphins and sea birds are most affected amongst the marine creatures. It is estimated that this ghost gear makes up 46% of the debris in the Great Pacific Garbage Patch (The Ocean Cleanup,2023). Most of these originate from informal or unregulated commercial fishing.
Underwater noise from shipping traffic, seismic exploration and sonar interferes with whale and dolphin navigation, breeding and hunting. Heated water from power plants and industries affects habitats and contributes to global change in climate.
All of these factors interact with each other and have a compounding effect on ocean water pollution.
The global scale of the crisis has been recognised by governments, international organisations and civil societies as well. The World Environment Day, UNEP's theme for the year 2025 was focused on plastic pollution and plastic waste in the oceans. #BeatPlasticPollution was a banner to stand behind, channelling the voices of the masses on social media. Yet while declarations are many, effective enforcement and global cooperation remain far behind the pace of environmental decline.
United Nations Plastic Treaty (2022-Present): It is an international effort led by UNEP to make a legally binding treaty to end plastic pollution by 2040. Around 170 countries are in negotiations. While focusing on curbing plastics from production to disposal, special attention is given to reducing the effects of marine water pollution (UNEP,2021).
30x30 Target: As part of the Global Diversity Framework, nations have committed to protecting 30% of the world’s ocean and land by 2030 (CBD.int, 2023).
The High Seas Treaty: It was adopted by the UN to protect biodiversity in international waters, especially from unregulated industrial fishing and mining.
While India produces only 11 Kg of plastic per capita, the sheer volume is a major issue. And in terms of ocean pollution, it’s one of the biggest contributors of global marine plastic pollution, owing mostly to a high mismanagement rate (TOI,2023).
Some efforts have been made by India:
Single-use plastics have been banned since July 2022.
The National Maritime Litter Policy has been drafted, which can reduce ocean plastic pollution.
The Swachh Bharat mission and AMRUT initiatives, aiming to modernise waste management, are underway.
However, the challenge is the implementation of the initiatives. Good intentions don’t reduce marine pollution. Actions to control and abate the causes of ocean pollution are necessary.
Overall, policies and pledges exist. But the gap between ambition and action continues to widen as marine life disappears and plastic waste in the ocean rises unchecked.
The scope of ocean pollution is quite huge. However, techniques to control and reduce them have been coming up and some solutions are already within reach. What is lacking is initiative on a larger scale.
The issue is that oceans are far away from our minds, so the social pressure on governments to take action is low. But the critical nature of the consequences of ocean plastic pollution should be made clear to the larger masses. This will put pressure to enact change.
Investment in robust waste collection and management systems and a circular economy for plastics should be made and distributed at the global level, especially to developing countries that lack infrastructure.
Projects like The Ocean Cleanup and Seabin Project offer scalable tools to remove floating plastic from oceans and ports. Remote sensing and AI-based marine monitoring can help detect illegal dumping, oil spills or ghost gear.
The most important part is strict implementation. It's the taxpayers' money that’s going into such initiatives. So they should be monitored and managed with efficiency like other mega projects.
UN treaties to protect the environment and other global frameworks need to be ratified by the countries and their contents enforced severely to cut down on the causes of ocean pollution.
Ocean recovery is very much possible. Studies have shown that with concerted global effort, marine pollution can be reduced and biodiversity regenerated by 2050 (Nature,2020). The time has come to take a further step from the diagnosis of reason to taking action.
The crisis of ocean pollution is no longer a distant issue but a global emergency unfolding in real time. Oceans may be far from our living place, but they form a major part of our lives. From the food on our plate to the ecosystem that we are a part of, all is connected to the health of the oceans. And as marine species disappear and ecosystems collapse, we are learning the hard lesson that the ocean’s capacity to absorb our waste is not infinite.
We still have time, but we have to act now. The science is clear, solutions exist and all that’s needed to be done is action with intent. Whether it's reducing plastic waste, reforming policy, or restoring marine habitats, the fight for our oceans is also a fight for justice, future generations and planetary balance. So, for our future, reducing plastic waste in the ocean is imperative.
