Pollution's Deadly Impact On Animals: Annual Death Toll

Pollution is causing an ongoing environmental and animal crisis that is becoming increasingly severe due to human activity. While the exact number of animal deaths caused by pollution annually is unclear, pollution is one of the leading causes of animal mortality worldwide. This includes air pollution, which has been linked to thousands of animal deaths, and plastic pollution, which has killed millions of marine animals through ingestion and entanglement.

Plastic ingestion by marine animals

Marine animals, from small finches to blue whales, are dying from ingesting plastic. Fish in the North Pacific ingest 12,000 to 24,000 tons of plastic each year, which can cause intestinal injury and death. Plastic ingestion also reduces the storage volume of the stomach, causing starvation. Research indicates that half of the sea turtles worldwide have ingested plastic, and some starve after doing so, mistakenly believing they have eaten enough because their stomachs are full.

A recent study found that a quarter of fish at markets in California contained plastic in their guts, mostly in the form of plastic microfibers. Sea turtles can choke, sustain internal injury and die, or starve by thinking they are full from eating plastic. On many beaches, plastic pollution is so pervasive that it is affecting turtles' reproduction rates by altering the temperatures of the sand where incubation occurs.

Marine animals that become trapped in plastic cannot find food, cannot find shelter, and trapped birds or mammals cannot swim up to the surface for air. Even if the plastic is removed, the deep cuts it can make in the flesh can become infected or draw the attention of predators. It is estimated that 60 percent of all seabird species have eaten pieces of plastic, with that number predicted to increase to 99 percent by 2050. Dead seabirds are often found with stomachs full of plastic, reflecting how the amount of garbage in our oceans has rapidly increased in the past 40 years.

Up to 13 million tons of plastic waste enters the ocean each year, threatening marine ecosystems and the people who depend on them. At current rates, plastic is expected to outweigh all the fish in the sea by 2050. Plastics pollution has a direct and deadly effect on wildlife. Thousands of seabirds and sea turtles, seals, and other marine mammals are killed each year after ingesting plastic or getting entangled in it.

Air pollution from farms

While it is difficult to ascertain the exact number of annual animal deaths caused by pollution, it is evident that pollution is a significant contributor to animal fatalities. Plastic pollution, for instance, is responsible for the deaths of over a million marine animals, including birds, fish, sharks, sea turtles, dolphins, whales, and more. These animals often ingest plastic or become entangled in it, leading to their demise.

When it comes to air pollution from farms, agricultural emissions play a significant role in degrading air quality. This includes emissions from tractors and farm vehicles, but the most substantial contributors are animal-raising operations. Cattle, pigs, and chickens release methane, nitrous oxide, and ammonia into the air. These gases not only impact the environment but also pose risks to human health.

Fertilizer use in farms is a major contributor to fine-particulate air pollution. Nitrogen-rich fertilizers emit fumes that combine with animal waste and industrial emissions to form solid particles, which are a significant source of disease and death. The production of artificial fertilizers has increased drastically, and it is expected to continue growing to meet the demands of an increasing human population.

Agricultural air pollution is not limited to the immediate vicinity of farms. Chemical drift from pesticides, herbicides, and fertilizers can reach nearby lands and neighborhoods, affecting air quality in surrounding areas. Ammonia emissions from farms are of particular concern, as they are the most significant contributor to particulate matter air pollution in European cities, accounting for 58% of the pollution.

While tighter regulations, cleaner energy sources, and improved vehicle efficiency are expected to reduce industrial emissions, it is crucial to address agricultural emissions as well. Projections indicate that farm emissions will eventually lack the necessary ingredients to create aerosols due to declining industrial emissions. However, this highlights the interconnectedness of various pollution sources and the need to address all source categories to effectively improve air quality.

Animals killed by wildfires

While the exact number of animal deaths caused annually by pollution is unclear, human pollution is undoubtedly having a devastating impact on wildlife. Plastic pollution, for instance, is known to have killed more than a million marine animals, including birds, fish, sharks, sea turtles, dolphins, whales, crabs, coral, krill, and more. Land animals, such as deer, camels, and elephants, are also victims of plastic pollution, mistaking plastic bags for food.

Wildfires, often caused or intensified by human activity and climate change, also result in the deaths of countless animals. In 2020, wildfires in the Pantanal wetland of Brazil, Bolivia, and Paraguay swept through 11 million acres of land, resulting in the deaths of over 17 million animals, according to researchers. This included species such as the northern rubber boa, great grey owls, Pacific martens, wolverines, and long-toed salamanders. The same year, wildfires in Australia killed an estimated 3 billion animals, including koalas, kangaroos, and other native species.

The impact of wildfires on animal life can be immediate, through burning, or gradual, as the destruction of habitats can displace species, making it difficult for them to survive in the long term. For example, wildfires in California have threatened the habitats of the spotted owl, which depends on old-growth trees and dense forest patches for nesting, roosting, and foraging. Similarly, pollinators may be at risk from fires that burn their habitats, as they can be directly killed by fires that burn faster than they can escape or burn them in their underground shelters.

The economic incentives of modern farming can also contribute to animal deaths during wildfires. In the context of large-scale industrial farming, it can be challenging to evacuate animals, and farmers may receive greater compensation for animals killed in a disaster than they would spend on evacuation, creating a perverse incentive.

Plastic entanglement

Plastic pollution is a pressing issue that poses a grave threat to various animal species, causing immense harm and loss of life. One significant way in which plastic contributes to animal deaths is through entanglement. Marine animals, such as dolphins, whales, seals, and sea turtles, often become entangled in plastic objects, leading to devastating consequences.

Entanglement in plastic can cause animals to drown, choke, or suffer physical trauma, such as amputation and deep cuts that can become infected. It can also lead to malnutrition when it prevents the animal from feeding properly. Seabirds, in particular, are severely affected by plastic entanglement, with millions of deaths occurring annually. The larger fragments of plastic can obstruct their gastrointestinal tract, preventing the plastic from being expelled. As a result, seabirds suffer from malnourishment, energy deprivation, and an increased risk of death.

Discarded fishing gear, including nets, lines, and other lost or abandoned equipment, is a significant source of entanglement for many marine animals. According to the World Wildlife Foundation (WWF), this abandoned fishing gear is one of the worst offenders when it comes to plastic pollution. The problem is not limited to marine animals, as land animals such as deer, camels, and elephants have also been affected by ingesting plastic.

The impact of plastic entanglement extends beyond the individual animals affected. The interconnectedness of marine life means that the repercussions of plastic pollution ripple through the entire food chain, affecting countless species. Sea turtles, for example, are susceptible to entanglement with large discarded fishing gear, posing a serious threat to these already critically endangered creatures. The presence of plastic debris in their habitats can also disrupt nesting sites and interfere with their reproductive behavior, further contributing to the decline in sea turtle populations.

Addressing the issue of plastic entanglement requires a collective effort. While there is no single solution, communities, governments, and businesses must work together to reduce plastic production, especially single-use plastic, and encourage plastic-free alternatives. Additionally, public awareness and small individual actions, such as reducing disposable plastic use and recycling, can make a significant difference in mitigating the impact of plastic entanglement on animal deaths.

Impact of microplastics

Microplastics are a type of plastic pollutant that is found in ecosystems and food chains worldwide. These tiny plastic particles, measuring less than 5mm in diameter, are prevalent in terrestrial, freshwater, and marine environments. They have been detected in various substances and organisms, from arctic ice to deep-sea sediments, raw milk, and the tissues of domesticated animals.

The impact of microplastics on wildlife is a growing concern. Due to their small size, microplastics can be ingested or inhaled by animals, leading to physical harm and exposure to toxic chemicals. Experimental studies on various species, including invertebrates, fish, mice, and rats, have revealed negative health effects, indicating pathological changes in different organs. The ability of microplastics to adsorb and transport chemicals is particularly worrying, as it leads to the bioaccumulation of pollutants within food webs, impacting animal behaviour, population dynamics, and ecosystem processes.

Furthermore, microplastics can carry pathogens that can infect both humans and animals. A recent study investigated three pathogens, Toxoplasma gondii, Cryptosporidium parvum, and Giardia enterica, which are persistent in the marine environment and can cause illness when consumed by humans through shellfish. These pathogens can associate with microplastics, particularly microfibres, in seawater, potentially transmitting diseases into the marine environment and posing risks to both wildlife and human health.

The presence of microplastics in the food chain is a significant issue. A recent study found that almost 80% of meat and dairy products from farm animals contain microplastics, with plastic particles detected in beef, milk, and all blood samples. The contamination is believed to originate from animal feed, as all samples of feed pellets and shredded feed contained plastics. This highlights the complex and varied detrimental impacts of microplastics on different ecosystems and species, with potential long-term consequences for both wildlife and human health.

While the full extent of the threat posed by microplastics is still being researched, the evidence suggests that their presence in the environment and food chains can lead to bioaccumulation, behavioural modifications, and adverse health effects in animals. The complex interplay between animals and microplastics underscores the need for interdisciplinary research to address this global issue and mitigate its ecological ramifications.

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