Fossil Fuels

Fossil fuels are organic substances that are removed from the Earth’s crust and used for energy. The remnants of decomposing biota (mostly plants and animals) naturally create carbon- and hydrogen-plentiful compounds (also known as hydrocarbons) as they become buried, compressed and heated over millions of years. Hydrocarbon deposits are then extracted from underground sources by way of mining, hydraulic fracturing, and drilling. Burning hydrocarbons produces heat energy which powers engines, generates electricity and supports industrial processes.

In the 21st century, fossil fuels are burned to meet most human energy needs. They also serve as the base for common plastic products, such as shopping bags, car parts, containers, electronics and clothing. Our reliance on fossil fuels is increasing the net amount of heat energy in the planet’s atmosphere, causing global average temperatures to rise. The resultant greenhouse gases from burning these fuels also contributes to ocean acidification, air pollution and water pollution.

Fossil Fuels Definition

The phrase ‘fossil fuels’ generically refers to hydrocarbon-containing materials formed by the burial of photosynthetic organisms (life forms that use sunlight to synthesize nutrients like oxygen and sugars from water and carbon dioxide). Hydrocarbons are molecules consisting of bonded hydrogen and carbon atoms. The stored energy in fossilized hydrocarbon compounds release energy in the form of heat when burned. Hydrocarbon combustion, the chemical reaction in which hydrocarbons interact with oxygen, also produces water and carbon dioxide.

How Fossil Fuels Are Formed

Fossil fuels are formed by geological processes acting on the remains of living organisms from millions of years ago. As fossil compounds become buried deeper and deeper underground, they are exposed to increasing amounts of pressure and heat, which transform them into coal, natural gas or oil. The form that the ancient remains take depends on the type of organic matter involved, the amount of time its been buried and the degree pressure and temperature. For example, plankton and algae can naturally transition from kerogen to petroleum if given enough time.

Fossil Fuels Used For

Fossil fuels have a diverse range of uses across sectors in civilization. Oil specifically, has byproducts that are used in pesticides and fertilizers. Natural gas is sometimes used to for refrigerating and cooling equipment, and to heat buildings. Coal, perhaps the most abundant fuel source, is critical for the generation of electricity. Fossil fuels may continue to dominate our energy economy because strategies and technologies for their extraction continue to improve.

Fossil Fuels Examples

Here are a few examples of fossil fuels, and products that contain them:

  • Propane
  • Butane
  • Peat products
  • Refinery feedstocks
  • Phones
  • Lubricants
  • Insulation
  • Solvents
  • Ink
  • Antifreeze
  • Diesel fuel
  • Motor Oil
  • Gasoline
  • Roofing materials
  • Detergents
  • Clothes made of synthetic fibers; including polyester, polyurethane, acrylic and nylon
  • CDs/computer disks
  • Glue
  • Petroleum Jelly
  • Fertilizers
  • Pesticides
  • Prosthetic limbs
  • Solar Panels
  • Asphalt
  • Cosmetics containing paraffin wax
  • Computer keyboards and monitors
  • Paints

Is SB 1383 Mandatory?

Californian flag and American flag
Californian and American Flags

Senate Bill 1383 (SB 1383) is California’s short-lived climate pollutant reduction law. The bill was enacted September 2019 to lower emissions of short-lived pollutants such as methane by 40%, relative to 2013 levels, no later than 2030. To achieve this objective, Californian food generators are being required to reduce their organic waste contributions.

California Landfill Methane Rule

SB 1383 limits the amount of organic decomposing material in landfills so that California’s total greenhouse gas emissions will decrease. Decomposing organic wastes, including foods, discharge so called “landfill gases” (LFG). LFGs are a combination of different greenhouse gases that are produced as organic wastes rot and break down.

In a sense, Senate Bill 1383 addresses food security and regional emissions reductions all at once. A fraction of food that would normally be disposed of in landfills or composts, must now be made available for human consumption. Some Californian households and businesses will have to initiate food recovery programs and or strengthen existing food recovery strategies.

Who Does SB 1383 Apply To?

SB 1383 requires specific food businesses to donate the maximum possible amount of edible food to food recovery organizations and for recycling. The law assumes two tiers for different kinds of edible food generators. “Tier One” includes supermarkets, grocery stores, food service providers and wholesale food vendors.

Restaurants, hotels, health facilities, certain education agencies and large venues and events are all considered “Tier Two”. Both tiers of food generators must donate as much food as they possibly can to food recovery organizations. Organizations and services that participate in SB 1383 are obligated to maintain records of the food being donated and the frequency of donations.

Who Passed SB 1383?

Edmund Brown Jr passed SB 1383 September 2016. Brown received his law degree from Yale and served as Governor of California from 1975 to 1983 and 2011 to 2019. By signing the bill into law, he established official methane emissions reduction targets that apply to most food generators across in the state.

Senate Bill 1383 California

Senate Bill 1383 went into effect January 1, 2022. By regulating organic waste disposal, California is expected to decrease its total greenhouse gas output while feeding hungry citizens at the same time. Organics may be recycled by composting and mulching. Some organic materials are converted into biogas, a renewable energy source, through a process known as aerobic digestion.

How Is Plastic Affecting the Arctic?

ice in the Arctic ocean
Ice in the Arctic ocean

A new review article, “Plastic Pollution in the Arctic“, contends that high levels of plastic pollution (including microplastics) have infiltrated the Arctic and intensified climate change’s effects. Plastics from agriculture, hydrocarbon exploration, landfills, illegal dumping, industry, households, fisheries, offshore industry and other such sources are routinely carried to and within the Arctic by atmospheric and aquatic circulation systems. As plastics move through the Arctic, they gradually break down and release greenhouses gases, including methane and ethylene.

Is There Plastic In the Arctic?

Transported plastics from local and distant sources are broadly distributed throughout the Arctic. The United Nations estimates that approximately 150 million tons plastic debris may be scattered across the Arctic. Plastics are found on Arctic shores, in the water column, in sea ice and in the bodies of marine biota.

How Does Plastic Pollution Affect Marine Life?

Arctic wildlife are known to ingest, become entangled in or smothered by plastic debris. “Plastic Pollution in the Arctic” reports that Arctic species such as sculpin (Triglops nybelini), the northern fulmar (Fulmarus glacialis) and belugas (Delphinapterus leucas) have been found with plastic inside them. Plastic ingestion may even affect marine invertebrates like zooplankton in the east Canadian Arctic and the Fram Strait (a sea channel between Greenland and Svalbard). The review further reports that the organismal impacts of plastic infiltration to many endemic species remain largely unknown.

The Fundamental Links Between Climate Change and Marine Plastic Pollution In The Artic

Plastics drive climate change, in return, climate influences distribution of plastics. Also, both climate change and plastics have oil and gas origins. Plastics are derived from greenhouse gases (GHGs) and continue to release GHGs throughout their life cycles as they degrade. Plastics and microplastics are thus expected to increase ocean heat content (OHC). According to “Plastic pollution in the Arctic”, plastics could also promote glacial thawing by affecting their light absorbance, structure and rheological properties.

Circulation systems, including wind, ocean currents and freshwater river flows, continue to move plastics through Arctic ecosystems long after they are originally introduced. Physical impacts associated with climate change effect the concentrations and distribution of plastic in the Arctic. Sea level rise or higher poleward wind speeds from global warming could transport greater levels of plastic debris to Arctic ecosystems.

These interactions suggest that climate change and plastic pollution are mutually reinforcing. The Arctic may be more sensitive to the effects of ocean warming and plastic pollution than most environments because of its permafrost, snow and ice. Climate change strategies aimed at mitigating ocean warming, will have to account for the emissions from plastic sources as well.

Are Climate Change and Plastic Pollution Related?

Plastic pollution and climate change are the most influential stressors to marine environments globally. These stressors are simultaneously occurring and interactive. Marine plastic pollution is made up of the plastic products that have accumulated in the world’s seas. From production to end-of-life, plastic materials release potent greenhouse gases, like carbon dioxide (CO2), methane (CH4) and ethylene (C2H4). Greenhouse gases from plastic materials contribute to ocean heating and exacerbate climate change.

Climate change refers to long term shifts in a region’s temperature or weather patterns. Climate events, such as flooding and storms, impact the concentration of plastic’s global distributions. A 2022 review titled “The Fundamental Links Between Climate Change and Marine Plastic Pollution” assembles evidence that demonstrate the feedback loops between climate change and marine plastic pollution.

How Does Climate Change Affect Pollution?

Plastics (including microplastics) are transported from place to place by way of winds, water flow patterns, and storms. Wind and storms can influence the dispersal of plastics. The same is true of flooding events and rainfall patterns. Climate change is already beginning to increase the frequency and magnitude of extreme weather phenomena, and will likely continue to spread plastics into novel environments, where they may disrupt ecosystems and or release heat trapping gases.

How Plastics Contribute To Climate Change

The 2022 review has three categories for plastic’s climate change contribution: “1) plastic production, transport and use; 2) plastic disposal, mis-managed waste and degradation; and 3) bio-based plastics”. From the very beginning of their life-cycle, plastic and bioplastics are greenhouse gas sources. Making plastic requires extracting organic materials, such as crude oil or plant matter, which are burned to be refined and processed. The resulting plastic must too be heated for molding and manufacturing. After use, the plastic product may be recycled, become landfilled, be incinerated, or end up an environmental pollutant. In each case, the plastic will emit more CO2 as it degrades or is melted, according to a 2019 study referenced.

Greenhouse Gas Emissions From Plastic Production

Climate change influences the distribution of plastic waste; plastic has substantial greenhouse gas contributions, which enhance ocean heating and climate change. Put another way, changes in climate and climate-driven extreme weather events influence the spread of plastic across environments, from oceans, to freshwater systems, to terrestrial areas. But co-concurrently, plastic influences climate change by releasing emissions twofold throughout its life-cycle; production (including refining and manufacturing) and after-use life (including landfills, recycling, incineration and environmental waste).

The Environmental Impact of GMOs

An article made available in Science Direct, 2022, unpacks the potential benefits that genetically modified crops have for reducing greenhouse gas emissions. Authors of the document, Emma Kovak, DanBlaustein-Rejto and Matin Qaim, claim that “genetically modified (GM) crops can help reduce agricultural greenhouse gas (GHG) emissions. In addition to possible decreases in production emissions, GM yield gains also mitigate land-use change and related emissions”.

How Do GMOs Affect The Environment?

GM (genetically modified) crops are agriculture plants that have had stretches of DNA added, effectively modified or turned off within their genome to achieve desired traits. GM crops are commonly designed to be more resistant to insects and tolerant to herbicides. Modified crops can therefore lower the need for chemical pesticides, which are greenhouse gas contributors. Also, yield increases from GM crop use may prevent greenhouse gas emissions from the conversion of natural land (land that is uncultivated) to cropland. Land conversions promote greenhouse gas emissions through tilling and forest clearing.

GMO Climate Change Strategy

The article contrives a hypothetical scenario in which the European Union (EU) lifts its “quasi-ban” against widespread GM crop use. Authors of the article assume that yield increases from genetically modified crop adoption in the EU would offer benefits similar to those observed in other industrialized, temperate-zone countries that use modified crops. They further assume that enhanced crop production in the EU will bring about proportional decrease in agriculture production elsewhere. The latter of these assumptions is built on the belief that land will be spared (remain uncultivated) because the EU will be producing more crops domestically, consequently shrinking land conversion demands in outside territories.

Avoided emissions estimates from increased yield are intentionally underestimated in the article. Although authors state that “…higher GM crop adoption in the EU would likely also lead to higher [technology] adoption elsewhere”, their avoided emissions estimates do not account for the implementation of technology related to genetically modified crop use.

Avoided emissions estimates also do not account for the implementation of novel modified crops and traits. In other words, estimates are strictly based on well known genetically modified crops (soybean, cotton, canola, maize, and sugar beet) and the traits that they are designed with.

GMOs Reduce Carbon Emissions

Even though estimates are based on already-existing technology for modified crop application as well as already-existing modified plants and traits, it may be fair to assume that new technologies and new crops and traits would emerge from increased modified crop adoption in the European Union. Authors of the article assert that the EU can and should “increase agricultural productivity through embracing new crop technologies, thus contributing to global environmental benefits”.

GMO Benefits

Adopting genetically modified crops in places like Europe, which has higher wheat crop loss levels-caused by insects and pathogens-that the global average, may result in improved crop growth by making vegetation more resilient to environmental stressors, such as disease, insects and herbicide application. Increased vegetation is expected to lead to enhanced soil fertility and improve carbon absorption in soils and biomass. By boosting crop yields in areas that have not broadly accepted genetically modified vegetation, tilling and forest clearing-related emissions can be mitigated.

Can Plastic Pollution Cause Climate Change?

An interesting review titled, “The Fundamental Links Between Climate Change and Marine Plastic Pollution”, describes the interactive relationship between climate change and marine plastic pollution. The review’s authors claim that climate change and marine plastic pollution are linked in three ways: a) the production of plastic relies on fossil fuel extraction and is thus a greenhouse gas contributor b) climate and weather influence the distribution and spread of plastic pollution across environments c) marine ecosystems and species are presently vulnerable to both climate change and plastic pollution.

plastic bottle in water

Greenhouse Gas Emissions from Plastic Production

The rise in plastic demand is likely due to its reputation as an inexpensive and lightweight material that has a wide range of uses. Plastic is used for packaging, electronics, toys, utensils, safety gear and infrastructure. Even so, plastic drives greenhouse gas emissions throughout multiple stages of its so-called “lifecycle”, from extraction and refining to transportation, incineration and recycling.

As common plastics degrade, they continue to emit greenhouse gases like methane or ethylene, which intensify ocean warming. Bio-based plastics, plastics made from biomass, are no exception. While bio-based plastics do produce fewer greenhouse gases than conventional plastics, they still release heat trapping molecules during their lifecycles. Degrading plastic products fragment into microplastics and smaller constituents parts that can be toxic to humans and marine organisms.

How Does Plastic Move Around the World?

Climate inevitably influences the movement of plastics between environments. Plastics are circulated by the flow of water and wind. Extreme weather, like floods and windy storms, can move plastics from one system to another. Flooding riverine systems can transport plastics into the ocean; tropical storms from oceans can push plastics into onto terrestrial surfaces. Releasing plastic into the ocean or onto landfills is not the end of that plastic’s life cycle. Plastic and microplastics continue to impact the ecosystems long after they have been disposed of by humans.

How Does Plastic Affect Marine Ecosystems?

Climate change is altering the distribution of many species by subjecting them to novel thermal conditions. When marine habitats heat up, the species within them are usually forced to move to new regions to find more suitable temperatures. Heating oceans also contribute to hypoxic zone and coral bleaching. Plastic, on the other hand, can is ingested by marine species, which can low survival odds. In some cases, marine animals become entangled by plastic products or have their feeding pathways obstructed.

Plastic also potentially facilitates species migrations because plastic debris attracts encrusting organisms and microbial communities. Therefore both climate change and plastic pollution can contribute to species movement between ocean regions. Increased species mobility can bring about invasive species risks.

How Does Plastic In the Ocean Affect Climate Change?

Authors of the review, “The Fundamental Links Between Climate Change and Marine Plastic Pollution”, reason that climate change and plastic pollution are fundamentally linked to one another. Plastic production is heavily dependent on fossil fuel use and the release of greenhouse gases as it degrades in oceans, both of which enhance ocean heating and climate change. Plastic dispersal across environments influenced by climate change-driven extreme weather. Marine ecosystems and species are vulnerable to these threats.

What Are Direct and Indirect Effects of Climate Change?

Freshwater systems provide usable water for technological development, agriculture and human consumption, while also serving as habitats for various aquatic species. Therefore, freshwater systems are of crucial economic and ecological value. A 2021 study titled, ” “The Importance of Indirect Effects of Climate Change Adaptations On Alpine and Pre-Alpine Freshwater Systems” asserts that human-made transformations in water hydrology and pollution from sewer outflows and agriculture chemicals are threats to freshwater systems. Properly accounting for the effects of climate change and anthropogenic influence on aquatic environments will hopefully improve climate change adaptation policies.

What Is Freshwater?

Rivers, reservoirs, and streams are examples of freshwaters systems. Freshwater is a subset of Earth’s water which is significantly less salty than marine waters (like seas and oceans). The United States Geological Survey, a branch dedicated to science within the United States Department of the Interior, defines freshwater as “water containing less than 1,000 milligrams per liter of dissolved solids, most often salt.” Though freshwater is renewed through the water cycle, it is a finite resource. If freshwater is used more quickly than it is naturally replenished, water security risks may be enhanced.

What Are Direct and Indirect Effects of Climate Change?

Authors of “The Importance of Indirect Effects of Climate Change Adaptations On Alpine and Pre-Alpine Freshwater Systems”, regard higher frequency of extreme meteorological events and increased temperatures as “direct effects” of climate change. These direct effects adversely influence the state and quality of aquatic regions. Direct effects also interact with human responses to climate change and produce “indirect effects”.

So-called indirect effects refer to human practices that are aimed at climate change mitigation. Indirect effects include land-use changes, alterations to freshwater systems and increasing irrigation practices. Authors suggest that “indirect effects may, at least in the short term, overrun the impact of direct climate change on water bodies.” Though all biomes are predicted to be impacted by climate change, freshwater systems in alpine and pre-alpine regions may be disproportionately at risk due to agriculture and hydropower plants.

Adapting Water Management to Climate Change

Freshwater use for the production of energy, also known as hydropower, is typically made possible by dams and in-stream structures. Hydropower infrastructure generates usable electricity for homes and businesses. Authors of the 2021 review article posit that hydropower is used as an alternative to nonrenewable energy resources. Hydropower production is therefore considered an adaptation strategy to climate change. Hydropower installations in freshwater networks can fragment or isolate certain species populations which are ill-adapted for the changes in water flow and perpetuate biodiversity loss. By modifying the hydrology of freshwater systems, water usage for energy production can compound the direct effects of climate change to aquatic flora and fauna.

How Does Agriculture Affect Climate Change?

Agriculture can be of detriment to freshwater systems as well, but in a much different way than hydropower plants. Climate change can intensify extreme weather event trends, such as floods, storms and droughts; these effects can drive diminished crop yields. In the interest of mitigating threats to crops brought on by climate change, agriculturalists may expand irrigation infrastructure or enhance fertilizer use. These adaptations can exacerbate the consequences which are already affecting crop growth cycles.

What Is the Impact of Climate Change On Water Resources?

Authors of the 2021 review claim that “rain-fed dairy farming is currently the most predominant form of agriculture, but in the future these grasslands may become more and more dependent on irrigation”. Redirecting water for irrigation use can potentially limit the quantity of water available in freshwater ecosystems. Variability in weather regimes may contribute to further dependence on water from irrigation (rather than from rainfall) in the future. Some of the responses that agriculturalists are expected to as a response to a changing climate pose risks to freshwater systems. Policy makers must account for indirect impacts to alleviate worsening the ecological status and water quality within aquatic environments.

Increasing Heat-Stress Inequality in a Warming Climate

Observed heatwave trends have been on the rise in the last four decades according to a research article published in January, 2022. The study titled, “Increasing Heat-Stress Inequality In A Warming Climate”, projects further intensification of extreme heat events in the future. Excess heat events like heatwaves are a symptom of increasing temperature averages across many regions of the globe. High temperatures are an immediate threat to human wellbeing as they may contribute to crop failure, worsened wildfires and or heat-related deaths, such as heat exhaustion and heat stroke.

How Is Heat Stress Related to Climate Change?

Researchers of the 2022 study assert that their “findings demonstrate continued increases in heatwave exposure inequality because of delays in adaptation capacity in the developing world, compounded by a higher emergence of warming in low-latitude areas where most of the low-income countries occur”. Societies in the lowest-income regions are projected to have greater difficulties adapting to the challenges posed by a warming climate.

thermometer on orange surface

How Does Climate Change Affect Heat Waves?

This study used heatwave data from the years 1980-2019, and modeled future temperatures for 2030-end of century. Heatwaves here are defined as “an event during which daily mean temperature exceeded the 97th percentile of local annual mean daily temperature in a reference period for at least three consecutive days”. Authors of the study claim that they are operating under the assumption that vulnerability to heatwave-related risks and degrees of suffering are determined by economic development status.

Thus, researchers split all regions of the world into four socioeconomic classes for income: lowest, lower-middle, upper-middle, and highest, (based on population-weighted per-capita gross domestic product in 2015). They were then able to create a spectrum for economic adaptive capacities. Adaptation capacities include cooling systems, electricity, early detection and warning systems and infrastructure.

As reported in the study, a 60% global increase in the total number of heatwave days were recorded over the past 40 years. Average yearly heatwave seasons were 75% longer during the 2010 years compared to those in the 1980s. Also, “the maximum decadal amplitude of shock heatwave was between 2.16 (Europe) and 3.27 (North America) °C higher in the 2010s as compared to the 1980s”. Although heatwaves intensified across all socioeconomic classes, the “low-income region” observed the rate of increase in heatwave season length yearly.

Which Place Is Most Affected by Climate Change?

In the 2010s, the “high-income region” experienced 30% fewer heatwave days. Sensitivity to heat waves is significantly determined by a society’s adaptation efforts. Regions with relatively low incomes will face greater challenges and vulnerability to heatwaves due to their lack of access to resources which enable adaptation across sectors. Inferior adaptation capacities may hinder or delay institutional heatwaves responses to heatwaves, making societies with lower scoring GDPs more susceptible to the impacts of rising temperature averages and excess heat.

What Is Causing Ocean Warming?

If you want to measure the rate at which global temperatures are rising, then the world’s oceans are perhaps the best places to observe. This is not only due to the fact that Earth’s surface is more than 70% water-covered, but also because ocean water absorbs 90% or more of Earth’s excess heat. Heat energy captured by ocean water is known as “ocean heat content”, which stores that heat for indefinite periods of time.

Ocean Heat Content

Because ocean water soaks up high proportions of atmospheric heat, they are essential for regulating Earth’s climate. Most of the ocean heating is stored at depths between 0 – 700 meters. Air would warm more rapidly without the ocean’s immense heat trapping capacity. Consequently, heat content builds near oceanic surfaces as they take on increasing amounts of heat.

Average Global Temperature by Year

A new analysis authored by 23 researchers that was published in the journal Advances in Atmospheric Sciences uses data across seven ocean basins to assess world ocean warming trends. The study titled, “Another Record: Ocean Warming Continues through 2021 despite La Niña Conditions”, finds that ocean waters have been monotonously increasing in temperature since the year 1958, and that the rate of change sharply quickened toward the end of the 1980s, with 2021 containing more heat energy than any other year on record since recordings began sixty years ago.

Was 2021 the Warmest Year On Record?

With this, 2021 beat the previous record set by 2020 as the year with the most heat energy in world oceans. The team used preexisting sets of data from various measurement devices in conjunction with climate model simulations to prove the accelerated rate of ocean warming in recent decades. It is then inferred that the relatively recent temperature spikes are mainly attributable to increased greenhouse gas concentrations brought on by human activity. The analysis asserts that “the increased concentrations of greenhouse gases in the atmosphere from human activities trap heat within the climate system and result in massive changes in the climate system”.

Table 1 from study: Another Record: Ocean Warming Continues through 2021 despite La Niña Conditions

Is the Climate Rising?

The study lists 2018, 2017, 2019, 2020, and 2021 (in order from least hot to most hot) as the hottest five years of the global ocean since the year 1955. These 5 years, which are quite recent and in close proximity to one another. This suggests that mean temperatures are approaching new highs.

Cowspiracy Ocean Facts Summary

Fisheries harvest marine organisms across the globe. While fisheries do generate food and profit, they could be doing much more harm than good for underwater ecosystems. The film Cowspiracy makes a convincing case for the deleterious affect that large-scale fishing operations have on ocean environments, species variety and species abundance. Cowspiracy depicts modern fishing as a largely unsustainable industry that could lead to fishless oceans by 2048.

fish near water surface
Fish near water surface

Fishing As Depicted By Cowspiracy

Fish and other marine life are mostly hunted as food. However, some species are used for other commodities. Sharks, for example, are sometimes hunted for their skin which can be used in the making of leather. Other species like whales and manatees are regularly harmed or killed unintentionally by getting caught in fishing nets. The Cowspiracy Facts page sites a Food and Agriculture Organization (FAO) document which states that in the year 2017, between 51 – 167 billion farmed fishes had been killed for food. That same year an estimated 250 – 600 billion crustaceans were also farmed and killed for food. Even animals that are not eaten by humans are caught and killed inadvertently because of drift netting or trawling. Susan Hartland of Conservation Society says that animal populations are being extracted from oceans more quickly than they can recover. Marine species are therefore collapsing under the immense pressures of modern hunting. The unintended catches, sharks, sea turtles and dolphins, are referred to as bykill.

Keystone Species and Trophic Cascades

Apex predators often act as keystone species, meaning that they have disproportionately large effects in their natural environments. This makes the removal of sharks particularly concerning. As top predators, many sharks species exert top down influence in their respective food webs. The removal of sharks, and other keystone species increases trophic cascade risks. Trophic cascades are the ecological chain of events triggered by the removal or addition of top predators.

Agriculture, Fishing and Algae Blooms

“Livestock operations on land have created more than 500 nitrogen flooded dead zones around the world in our oceans…” According to Dr. Richard Oppenlander, an environmental researcher featured in the Cowspiracy film. Water pollution comes in the form of pesticides, herbicides, heavy metals, plastics and other waste material. However, animal agriculture is the leading cause of ocean pollution – a fact which is stated explicitly in the Cowspiracy film. Animal agriculture run-off upsets nutrient balances in aquatic ecosystems by introducing phosphorus, nitrogen, manure and potassium from chemical fertilizers. These excess nutrients can cause alae blooms, leading to uninhabitable zones for marine species. Blooms of algae drain sunlight and deplete oxygen levels – making the environment unsuitable for most other lifeforms in the ecosystem.

Bottom trawling contributes to inhabitable zones similarly. Bottom trawling, also referred to as “dragging” involves casting a fishing net to the sea floor. Trawling disturbs sediments along the sea floor which causes carbon to be released. Once carbon dioxide is released from sediments, it is then absorbed by ocean seawater. Elevated carbon levels allow water to trap in more heat and further facilitate algae and plant overgrowth.