Ocean Pollution: A Vast And Growing Crisis

The ocean is one of the most valuable natural resources on Earth, covering more than 70% of the planet and providing a living for millions. However, human activity has led to a significant increase in ocean pollution, with plastic being one of the most prominent pollutants. Plastic pollution in the ocean has become a global crisis, with an estimated one to two million tons of plastic entering the oceans each year, and it is expected that by 2050, plastic will outweigh all the fish in the sea. This plastic pollution has had a devastating impact on marine life, with thousands of marine animals dying from ingestion or entanglement in plastic. In addition to plastic, other sources of ocean pollution include oil from vehicles and boats, chemical discharges, sewage overflow, and agricultural runoff, all of which contribute to a decline in ocean health and the destruction of ecosystems.

Marine debris

The majority of marine debris comes from human activities along coastlines and far inland, with eighty percent originating on land. It enters the ocean through littering, poor waste management practices, stormwater discharge, and extreme natural events such as tsunamis and hurricanes. Some debris, such as lost fishing gear, also comes from ocean-based sources. This abandoned gear is a significant issue as it can continue to capture and kill wildlife, damage habitats, and interfere with active fishing.

Once in the ocean, marine debris can be challenging to track and remove. It can be found from the surface to the ocean floor and has even been discovered in the deepest parts of the seafloor, remote shorelines, and Arctic ice. Marine debris can injure or kill marine and coastal wildlife, such as seabirds and sea turtles, damage and degrade habitats, and interfere with navigational safety. It can also cause economic losses to fishing and maritime industries and degrade the quality of life in coastal communities.

The NOAA Marine Debris Program addresses marine debris by funding projects that remove debris from shorelines and prevent it from entering the ocean. These projects include outreach, education, and community-based removal initiatives. Since 2006, the program has supported over 340 removal projects and removed more than 40,000 metric tons of marine debris from coasts and oceans.

Plastic pollution

It is estimated that 8 to 11 million metric tons of plastic enter the ocean each year, with about 0.5% of plastic waste ending up in the ocean. This plastic waste comes from a variety of land and ocean-based sources, including littering, improper manufacturing processes, and industrial fishing. The majority of plastic pollution in the ocean is caused by the improper disposal of disposable plastic items such as food wrappings, plastic bags, bottles, and single-use items. These plastics can take hundreds of years to degrade and often end up in what are called "garbage patches," with the Great Pacific garbage patch between Hawaii and California being the largest.

The impact of plastic pollution on marine life is devastating. Animals can mistake plastic debris for food, leading to ingestion, suffocation, internal injuries, and death. It is estimated that half of the world's sea turtles have ingested plastic, and thousands of seabirds, seals, and other marine mammals are killed annually due to plastic pollution. Additionally, microplastics can absorb harmful pollutants like pesticides and release them into the ocean, further exacerbating the issue.

To address plastic pollution, it is crucial to improve waste management practices, especially in low-to-middle-income countries, and reduce the use of disposable plastic items. Governments can play a role through public awareness campaigns, incentives for recycling, levies, and banning certain products. Individual actions, such as reducing plastic consumption, reusing and recycling plastic items, and participating in local cleanups, are also important in tackling this global crisis.

Nonpoint source pollution

The effects of nonpoint source pollution can be harmful to both the environment and human activities. It can make water unsafe for humans and wildlife, leading to beach closures and negatively impacting recreational activities. It can also affect the commercial fishing industry and the overall quality of life in coastal communities, potentially driving down property values. Additionally, nonpoint source pollutants can lead to mass die-offs of fish and dirty-looking water, resulting in financial losses for communities that depend on tourism and fishing.

To address nonpoint source pollution, organizations like the US Environmental Protection Agency (EPA) and NOAA's Coastal Zone Management Program have developed control plans and initiatives. The Clean Water Act, for instance, has helped limit both point-source and nonpoint-source pollution in the United States, leading to cleaner water today than in most of the 20th century. Other efforts include educational resources and federal programs that aim to raise awareness and encourage public involvement in nonpoint source control.

While nonpoint source pollution is a significant issue, ongoing efforts and initiatives provide hope for mitigating its impact on the environment and human communities.

Oil and carbon emissions

Oil spills are a major source of ocean pollution, but they account for just 12% of the oil found in our oceans. Two to three times as much oil is carried out to sea through runoff from roads, rivers, and drainpipes.

Nonpoint source pollution, which occurs as a result of runoff, is one of the biggest sources of ocean pollution. Marine debris, which includes derelict fishing gear and abandoned vessels, is a persistent problem that threatens marine life, habitats, navigation safety, and even human health. This debris comes from people, with littering, poor waste management practices, stormwater discharge, and extreme natural events like tsunamis and hurricanes being major contributors.

In addition to physical debris, the ocean absorbs about 30% of the carbon dioxide (CO2) released into the atmosphere. As levels of atmospheric CO2 increase due to human activities such as burning fossil fuels and changing land use (e.g., deforestation), the amount of carbon dioxide absorbed by the ocean also increases. This has led to ocean acidification, which has far-reaching implications for marine life and ecosystems. The pH of surface ocean waters has already fallen by 0.1 pH units since the Industrial Revolution, representing a 30% increase in acidity. This change in seawater chemistry has already impacted the shellfish industry, and researchers are working on solutions to minimize the effects of ocean acidification.

To address the root cause of ocean acidification, it is crucial to reduce unabated CO2 emissions from the burning of fossil fuels. This can be achieved by transitioning to zero-emission energy sources, such as hydrogen, ammonia, methanol, or wind power. Green shipping corridors, which support zero-emissions technologies, are already in place across the Pacific and Atlantic oceans, accelerating the decarbonization of the shipping sector.

Noise pollution

Human activities such as commercial shipping, sonar use, exploration, construction, seismic surveys, and naval exercises are the main contributors to the rising levels of noise pollution in the ocean. The sound of a ship's propeller cavitation, hull vibrations, and diesel engines can cause noise pollution, with frequencies ranging from 10 Hz up to 1 kHz. Cargo vessels, in particular, produce very low-frequency sounds that can travel hundreds of kilometers underwater. Marine dredging, oil and gas drilling, and the placement of offshore structures also increase sound levels in the ocean. The noise produced by these human activities can be as high as 135-230 decibels, which is comparable to the sound of a rocket launch.

The impact of noise pollution on marine life can be severe. It can interfere with the detection of acoustic signals, masking the sounds produced by marine wildlife and disrupting their natural behaviour. For example, sonar has been recorded to alter the feeding behaviour of endangered blue whales, causing them to stop feeding, increase their swimming speed, and move away from the sound source. Noise pollution can also cause hearing loss and physical trauma, including internal bleeding. It can disrupt migration routes, pushing animals into regions with insufficient food or outside their thermal range, which can lead to population declines.

To address this issue, global initiatives and organizations are working towards regulating and mitigating ocean noise pollution. The International Ocean Noise Coalition (IONC), with representatives on every continent, was created to establish a global approach to combating human-generated ocean noise. The United Nations (UN) has also passed resolutions to address noise and protect marine biodiversity, and the International Maritime Organization (IMO) has established guidelines encouraging quieter ship designs. In addition, industries are exploring quieter alternatives, and there is a growing shift towards renewable energy sources, which can help reduce noise-intensive activities.

Frequently asked questions