HOW WE FILLED THE OCEANS WITH PLASTIC IN JUST OVER 60 YEARS
“Man-made items of debris are now found in marine habitats throughout the world, from the poles to the equator, from shorelines and estuaries to remote areas of the high seas, and from the sea surface to the ocean floor.”
Impacts of Marine Debris on Biodiversity, UNEP Report, 2012
Seabirds lead a precarious existence. Their marine habitats worldwide are littered with so much plastic waste that they often mistake plastic for food. Scientists recently estimated that by now 90% of all individual seabirds have ingested plastic debris, compared to only 5% in 1960.
This finding is alarming yet not surprising. Roughly 8 million tons of plastic garbage pollute the oceans each year and concentrations can reach up to 580,000 plastic pieces per sq km. 80% of these plastics originate from land-based sources (inadequate waste management systems, industrial activities, tourism-related litter, etc) and 20% from ocean-based sources (fishing gear, cargo vessel mishaps, recreational boaters, offshore oil and gas platforms).
This trend is not expected to stop and it is likely that “plastic will be found in the digestive tracts of 99% of all seabird species by 2050 and 95% of the individuals within these species will have ingested plastic by the same year”. However, seabirds are not alone to suffer. The impact of plastic pollution is global and affects numerous marine ecosystems and wildlife.
A COSTLY DAMAGE TO MARINE ECOSYSTEMS AND BIODIVERSITY
Plastic pollution directly impacts biodiversity and is progressively degrading marine ecosystems worldwide, a process that costs an estimated $13 billions each year. More than 660 avian and non-avian wildlife species, including all sea turtle species, have been reported to suffer damage or die from plastic encounters. Of those, 15% are vulnerable, endangered or critically endangered according to the IUCN Red List.
Plastic harms and kills seabirds and other marine wildlife primarily through ingestion and entanglement.
According to the 2012 UNEP report on the impacts of marine debris on biodiversity, ingestion of plastic debris “[compromises] the ability to capture and digest food, sense hunger, escape from predators, and reproduce as well as [decreases] body condition and [compromises] locomotion, including migration”. Microplastics, i.e. fragments smaller than 5mm and often invisible to the naked eye, are particularly problematic because they can be ingested by a larger variety of organisms, including the fish and other seafood we consume. Entanglement, especially by discarded or lost fishing gear that continue ghost fishing for a long time, drowns, chokes, cuts, and starves the animals who get trapped in them.
Plastic also harms marine wildlife through more insidious ways we are only beginning to understand.
Chemicals commonly found in plastics like bisphenol A (BPA), phtalates and antimicrobials, known to have deleterious effects on human health, have been found at toxic levels in the oceans. No field studies are yet available, but lab experiments on animals have shown that such harmful chemical concentrations can affect reproduction, impair development, cause genetic aberrations and damage tissues and organs. Moreover, plastic debris, especially microplastics, soak up pollutants already present in the oceans from other anthropogenic waste sources (illegal dumping and run-offs from land-based activities) thereby introducing them to the food chain. Small marine organisms can hitch-hike on floating plastic debris and be transported and dispersed to new areas where they may become invasive.
A GROWING AND PERVASIVE FORM OF POLLUTION
Awareness of marine plastic pollution goes back more than half a century, at the time when the modern plastic industry started taking off. The first accounts of plastic in marine environments came from carcasses of seabirds collected from shorelines in the early 1960’s. In the 1970’s, studies revealed that floating plastic debris were widespread on the oceans’ surface, especially in the Pacific Ocean, and the first cases of wildlife entanglement by fishing nets were reported in New Zealand, Alaska and Southern Africa.
From the early 1980’s, the presence of plastic debris in the oceans began to be recognized as a national and international pollution hazard. The first and second international conferences specifically dedicated to marine debris were held in Honolulu in 1984 and 1989. Both made recommendations to address the problem, but neither these meetings or the ones that followed prevented marine plastic pollution from exacerbating and becoming global.
As plastic production grew exponentially from 5 million annual tons in the 1960’s to nearly 300 million tons in the present decade, increasingly more plastic waste found its way to the oceans. This trend is not slowing down, on the contrary: by 2050, global plastic production is expected to reach 400 million annual tons.
According to the 2015 Worldwatch Institute report titled Global Plastic Production Rises, Recycling Lags, “With a market driven by consumerism and convenience, along with the comparatively low price of plastic materials, demand for plastic is growing”, especially in developing countries like China where middle-classes are expanding. Much of the plastic retained at sea is indeed post-consumer plastic waste, i.e. plastic waste derived from consumed or used consumer products (household goods, clothes, food packaging, automotive parts, etc). A considerable portion of this waste stream consists of plastic bottles and plastic packaging, the fastest growing form of packaging, which currently represents one third of total packaging sales.
The durability of plastics means they can remain almost endlessly in the oceans and travel thousands of miles. Plastics wash ashore or get trapped in the five oceanic gyres (see map for definition), most severely in the Great Pacific and North Atlantic Garbage Patches. There, debris is broken down into smaller pieces by bacteria and UV radiation. Depending on their density, they may keep floating at the surface or sink to the seafloor.
That such a recent form of pollution, unleashed just over 60 years ago—barely a human lifetime—could reach this magnitude is appalling. States are failing to implement effective processes for the recovery of plastics, and most importantly, are unwilling (unable?) to turn around the current system of overproduction and overconsumption, which is the real source of the problem.