Causes of risk

• Humans have impacted oceans, land and even space with artifacts.

• On earth, this is done for exploration, agricultural, urban development, forestry, mining and environmental pollution.

  • This affects both biotic (living organisms) and abiotic (environmental) factors.

• This can cause extinction in extreme cases.

Classifications

• The IUCN (International Union for the Conservation of Nature) assesses and grades organisms based on their vulnerability for extinction. This is based on numbers, rate of decline and overall distribution:

  • EX - Extinct

  • EW - Extinct in the Wild (meaning members of the population are in zoos or other conservation programmes)

  • Threatened:

    • CR - Critically endangered

    • EN - Endangered

    • VU - Vulnerable

  • NT - Near threatened

  • LC - Least Concern

• There are two other classifications, DD (data deficient) and NE (not evaluated). These species may still be threatened, but have not been researched enough to prove this.

• Results of these ratings are published in Red Data Lists.

Extinction

• This is a natural process that has occured since the beginning of life, at a background rate of 10-6y-1 (each year, one species in a million becomes extinct).

  • This can happen due to climatic, geological and biotic changes - which are natural.

• However, human intervention is now the major cause of extinction, and has increased these extinction rates to around 1000-10,000 times the average.

• Examples are:

  • Some megafauna (very large animals), such as:

    • Moa, a giant bird from New Zealand.

    • Giant ground sloth, from South America.

  • Passenger pigeon, from North America.

  • Thylacine, from Tasmania.

  • All warm water coral reefs are predicted to die by 2050, which 33% of marine life relies upon.

• There are also mass extinctions, where a vast majority of species have been killed by a major change, such as in temperature or ocean acidification. There have been 5 of these so far.

  • Human activity may be causing the sixth.

Reasoning for extinction

• There are direct reasons:

  • Loss of habitats:

    • Deforestation - Cutting down trees.

    • Drainage of wetlands - Can be caused by droughts, or human intervention for agricultural use.

    • Hedgerow loss - Hedges separate fields, and provide insect habitats, nesting sites for reptiles and birds, food for many species and a varying light intensity and water availability for diverse plant species.

      • They also act as wildlife corridors to enable species to move from one area to another, maintaining biodiversity.

      • They are often removed for agricultural equipment, decreasing herbivores and other consumers - a loss felt higher up trophic levels.

    • Seasonal crop planting - Plants are often sowed in autumn over spring, meaning plants are not high enough for birds to build their nests, decreasing bird populations.

    • Agricultural exploitation - Land is abused for agriculture.

  • Overhunting:

    • Trophy hunting - Animals are killed for their heads to be used as trophies, or ivory from horns.

      • Countries that allow this require payment, and claim only old and sick animals are targeted.

    • Traditional practices - Bones and ivory are used in medical practices, which don’t actually work.

    • Bush meat industry - Kills primates and other wild animal for food. Banned in the UK.

    • Overfishing - excessively hunting specifically ocean dwelling animals.

  • Invasive species - These are non-native species which are introduced to a different ecosystem and alter the biodiversity. This is usually due to the fact they have no natural predators. Examples are:

    • Dodos were driven to extinction as rats ate dodo eggs. Rats have also diminished native species on the Galapagos islands.

    • The North American crayfish has entered streams in the UK, out competing the smaller native crayfish.

    • Native Red squirrels are outcompeted by the North American grey squirrel in the UK.

  • Pollution:

    • Oil - This is shipped worldwide in supertankers, which are too big to enter ports. These accidentally discharge oil and when they run aground (accidently impact some form of land) they can cause major spills.

      • This contaminates drinking water and poisons the environment.

      • Oil floats, preventing oxygenation of surface water, killing those beneath it. Those who break the surface, such as birds, are covered in a film of oil. This causes their feathers to clump together, preventing insulation and are therefore chilled to death. Shore-dwelling animals ingest washed up oil, and poisons them.

    • PCBs - Also known as polychlorinated biphenyls, were used for electrical equipment lubricant as they don’t burn easily.

      • These are carcinogens, hormone disruptors and neurotoxins when ingested.

      • Their use is banned, and although manufacture stopped in Newport in 1970s they are still detected in water from the site.

• There are also indirect reasons, which can be natural but are exacerbated by the above list:

  • Natural selection - Species are not adapted to current circumstances, and therefore reproduce less successfully.

    • Species can no longer adapt fast enough to changing conditions caused by humans, and therefore die.

  • Non-contiguous populations - Groups of the species are separated, causing them to act as separate populations. This lowers genetic diversity.

Agricultural exploitation

• Agriculture is used to feed the human population, but can often harm biodiversity. In the last 70 years, exploitation has had many negative effects:

  • Hedgerows were removed to make room for machinery.

  • Larger fields are used for monoculture (the growing of a single plant). This means there is only one habitat, while many plants provides many areas for animals to live. This reduces species diversity.

    • If the same crop is replanted on the same field multiple times the yield decreases as roots are all the same length and therefore extract the same materials from the same depth. These plants are also susceptible to the same pests and disease, meaning the same pesticides are constantly used.

  • Cattle can overgraze grassland, making it unsustainable. Their hooves compact soil, driving out air and preventing water from entering. Additionally, roots cannot penetrate the soil.

• Farmers have national schemes to encourage them to stop these practices, and receive subsidies for giving land over to conservation.

Deforestation

• This can be done for agriculture, but also as timber is used as a building material, paper, fuel and packaging. It can also be used to build roads.

• High value trees are targeted, harming the trees around them.

• Deforestation causes:

  • Soil erosion - Tree roots bind soil together, and when removed, allows for the movement of the soil.

    • Topsoil (fertile soil) on higher valleys can be swept away by heavy rain. This leaves no soil for crops to grow.

  • Lowland flooding - Caused as uplands have no reason to store water, or ability to.

  • Soil devaluing - The water cycle of a forest is disrupted, harming the soil.

    • Normally, leaf litter, plants and humus soak up heavy rainfall and gradually release it into the soil, which cannot be done after deforestation.

    • Water evaporating from soil is slower than transpiration, leaving the soil wet for longer. This takes up the soils airspaces, decreasing oxygen available for plants.

    • Wet soils also take longer to heat up, decreasing root activity and germination.

    • This soil also helps grow denitrifying bacteria, taking away the soil’s fertility.

  • Habitat loss - 50% of earth’s species live in tropical rainforests, and taking away their habitats can cause extinction. It is estimated deforestation causes the extinction of 25 plant and animal species daily.

  • Atmospheric effects - Carbon dioxide levels are increased, as there are less plants using it in photosynthesis.

    • Additionally, excess trees are often burnt down, releasing carbon dioxide.

Forest management

• A traditional method is known as ‘slash and burn’.

  • This is where a small area is cut and the trees are burned. The ashes are used as fertiliser for plants, and when the land becomes infertile it is left alone to regenerate.

  • However, this is only sustainable on a small scale.

• In Britain, coppicing has been used for thousands of years.

  • This is when a tree trunk is cut to a stump. New shoots emerge from the stump, which thicken over time. They are then cut on rotation.

  • The longer rotation time, the higher sustainability as a variety of habitats can be allowed to develop.

• Selective cutting is used in areas with high slopes which are vulnerable to soil erosion.

  • This is where only some trees are cut down, allowing the environment to maintain itself.

• Good forestry practice is also necessary:

  • Planting trees a good distance apart is necessary to prevent intraspecific competition.

  • Pests and diseases should be controlled for to allow for good quality timber to be produces, reducing the amount of trees required.

  • Cutting the same amount of trees each year allows for the ecosystem to maintain itself.

  • Native trees should be planted when possible, in order to maintain natural biodiversity.

Overfishing

• Commercial fishing techniques have caused overfishing:

  • Trawlers - Large nets dragged across the bottom of the sea floor, damaging the ocean bed which is a habitat for many animals.

  • Drift netting - Nets are stretched across two boats and dragged through the ocean, often catching animals that are not fish, such as dolphins.

• Due to the large amount of fish captured, fish populations cannot sustain themselves and fall dramatically.

• Additionally, due to the small mesh baby fish cannot escape, meaning no fish are left to reproduce.

• Important prey species for fish, such as capelin and krill, are also captured. This also contributes to the decline of fish populations.

• Local fishermen are also harmed, as there is not enough fish left for them to catch.

Regulatory methods

• Mesh size can be controlled to allow younger fish to escape. Legislation prevents fish being sold below a certain size to support this.

• Quotas can be set to only allow a certain amount of fish to be brought back to land, however the fish over these amounts can be discarded into the sea dead.

  • The EU recognises this as a problem and is working to make this practice illegal.

• Exclusion zones prevent fishing during certain times of the year, allowing fish to reproduce. This is enforced using satellite technology to track trawlers, who are fined.

• Fish can be certified by the Marine Stewardship council, which ensures the fish are obtained from sustainable practices.

• Legislation can be used to control the size of fishing fleets and the number of days they can spend at sea.

• Fish farming can also reduce the need for overfishing.

Fish farming

• This is when fish are kept in enclosures in estuaries to maintain food supplies and decrease predation.

• They are sometimes farmed on a pod, which is a large steerable device that can be moved dependent on water currents, water temperature and other abiotic factors.

• Artificial fertilisers are used to increase the growth of phytoplankton, as well as warm water.

• Fish also have advantages over land meat, as they are more edible, produce a lower carbon footprint and convert their food into protein more efficiently.

• However, there are many disadvantages:

  • Disease spreads easily as they are often densely stocked. Therefore huge doses of antibiotics are required to keep them healthy, as well as pesticides, which can also harm marine invertebrates.

  • Pollution is caused as the ecological balance of waterways can be disturbed, causing eutrophication - the overgrowth of algae which blocks oxygen from reaching fish. This is caused due to fish excrement, fertilisers and waste food being carried to the water surrounding the pens.

  • Escaped fish can out compete native fish for food, habitats and mates as they are selected by farmers for rapid growth. Once they interbreed with native fish, they can form colonies of fast-growing fish which can drive wild fish to extinction. They can also transmit disease to these wild fish.

  • They can overuse resources, as salmon require three times their weight in food, which is made from other fish.

  • Environmental toxins, such as methyl mercury, dioxins, pesticides and PCBs are in higher concentration in farmed fish than wild fish.

  • Environmental degradation, such as the salinisation of soil and groundwater and mangrove destruction is often blamed on the shrimp industry.

Conservation

• This is the sensible management of the biosphere (parts of Earth where life exists) to enhance biodiversity while allowing for human activity to continue.

  • It also maintains genetic diversity in the wild and in captivity.

• It can be maintained on different levels using different strategies:

  • Local:

    • Protection of habitats - This protects the area and the species that live there.

      • Official designation recognises local nature reserves, as small as a few hectares. There are also SACs (Special Areas of Conservation) and SSSIs (Sites of Special Scientific Interest).

      • These have varying levels of legal protection, and can be managed by wardens.

  • National:

    • Gene banks - The protection of certain species by keeping them in captivity.

      • Sperm banks store genes of economically important animals and threatened species. These can be sent around the world instead of animals, decreasing risks.

      • Seed banks maintain seeds of traditional varieties and those vulnerable, via storing them in highly controlled conditions such as in liquid nitrogen. These can degrade over time, so are periodically thawed and germinated. The seeds they then produce are stored. These are highly valued as they contain food seeds, which are a potential food stores if current plant species are harmed.

    • Breeding programmes are implemented in special zoos and botanic gardens. Their genetic history is tracked to ensure genetic diversity is achieved.

      • Species reintroduction can be done when breeding programmes are successful, and animals are placed back in their native environments.

    • Rare breed societies maintain less commercial animals for their special characteristics, such as sheepdog associations.

    • Education:

      • This focuses on public awareness campaigns. In the UK, the Countryside Commision promotes nature conservation by proposing schemes, advises the government and groups and establishes nature reserves.

  • International:

    • Legislation - Laws that protect certain areas and trade to enhance biodiversity.

      • Ivory is restricted in most countries, as well as whaling.

      • EU has laws that prevent plant picking, wild plant picking, collection of bird eggs, game hunting, overfishing and overgrazing.

    • Ecotourism - This practice recognises the harm that mass travel to certain areas does to the environment.

      • It aims to use money from tourism to contribute to conservation efforts, hire locals, educate visitors on the local culture and how to respect the area and cooperate with locals to manage local areas of biodiversity.

Why this is important

• Some ecosystems are at higher risk, such as coral reefs and rainforests. These areas have more biodiversity, and therefore require more protection.

• Reasons for this protection include:

  • Ethical reasons - Each species is unique, and therefore deserves protection.

  • Agriculture and horticulture - These plants and animals have been developed from wild versions, but through selective breeding have developed genetic uniformity.

    • This may cause issues as certain genes may be underrepresented, such as cold or disease resistance.

    • These then need to be breeded back into cultivated plants, which is not possible if the wild plants go extinct.

  • Potential medical uses - Some medicines come from plants, and it is highly likely some plants yet to be discovered may have medicinal values.

    • If these go extinct, this value would never be discovered.

Sustainability

• Environmental monitoring describes the quality of the environment, by establishing the current status and comparing to the past to identify trends. There are many types:

  • Air quality monitoring - Concentrations of pollutants are measured due to their possible health effects. This can be carried by the wind.

  • Soil monitoring - Looks at soil structure, density, water-holding, drainage capacity, pH, organic particles, earthworms, and other organisms - by measuring enzyme activity and respiration rate.

  • Water quality monitoring - Looks at several aspects of water:

    • Chemical - This has been made essential in the last 30 years due to acid rain and greenhouse gases.

      • Since 1960s, environmental oestrogens in water supplies has increased due to use of oral contraceptives and industry materials. This may have a feminising effect on aquatic organisms and humans, such as embryo development and during puberty.

    • Biological - Animals can act as indicator species, such as loss of salmon indicating acid rain, mosses indicating heavy metal concentrations, and eels fat accumulating halogenated organic chemicals.

    • Microbiological - Bacteria and viruses monitored in drinking water.

      • Sewage plants can release water without sterilisation into rivers. It can have high bacteria counts, such as coliform. If this is high enough, it is tested for other specific pathogens and treated.

Assessments

• Statistical analyses of environmental monitoring data is performed by dedicated software packages. This data can be used in environmental impact assessments.

• Collaboration is needed across different areas, such as mathematicians, geologists, economists, archaeologists, etc.

  • These documents aim to predict environmental effects of proposed projects that may harm the environment. These environmental impact assessments began in 1985. They include:

    • Description of the project and site.

    • Alternatives that have not be considered, such as cleaner energies.

    • Environmental description. Organisations with crucial local knowledge have input.

    • Description of significant effects on the environment.

    • Mitigation - ways to avoid negatives impacts and proof these have been considered.

      • Examples are wind farms being built when birds aren’t nesting.

      • Proposed roads to avoid certain environmental hotspots.

Planetary boundaries

• This concept was introduced in 2009 to define the safe operating space for humanity.

• There are nine identified, and exceeding any is likely to result in catastrophic and unpredictable events to the planet.

  • These nine can be categorised as high risk, safe or not quantified.

Climate change

• This is one of the two core boundaries, meaning crossing it with have severe consequences.

  • It is classed as high risk.

• Even if all greenhouse gases ceased, the temperatures could continue to rise for centuries.

  • This will lead to the sea level rising by 7m by 2100.

• An alternative to greenhouse gases is biofuels, which are made by anaerobic digestion of plant material or agricultural, domestic and industrial waste.

  • As plants are used, this can offset the carbon released by burning.

  • The International Energy Agency aims for 25% of the world’s transport to use biofuels by 2050.

  • First generation biofuels are made from arable crops, second generation from woody crops which are harder to extract.

  • It is made around the world in industrial installations and domestic digesters. It is also produced naturally at landfill sites.

• There is concerns as a large amount of planting space is needed, meaning there is risk of unsustainable farming practices or taking up room for agricultural crops.

• There are many types of biofuels:

  • Bioethanol - Made by fermenting the carbohydrates in sugar or starch crops.

    • This is the most commonly used, and car petrol engines can use up to 15% ethanol alongside petrol. It is made in several stages:

      • Plant material is crushed and digested with carbohydrases to release sugars. The remaining crushed material is known as bagasse.

      • Sucrose is crystallised to leave out molasses, as this is rich in glucose and fructose.

      • These are fermented with yeast to produce a mixture containing ethanol.

      • This is heated by burning the bagasse from the initial plant material to distill pure ethanol.

  • Biodiesel: Made from vegetable oils and algae, due to their long chain fatty acid content.

    • Most widely used biofuel in Europe.

    • Made by reacting fatty acids with an alcohol, usually methanol, to produce methyl linoleate, or biodiesel.

    • Has less carbon, so produces less carbon dioxide and more nitrous oxide.

    • Pure biodiesel can be used in car engines, but is often mixed with diesel to reduce emissions.

  • Biogas - A mixture of gases, usually 60% methane and 40% carbon dioxide.

    • It is created by bacterial digestion of biodegradable waste materials, such as human and animal waste or energy crops. It occurs in three stages:

      • Macromolecules in waste material are aerobically digested by amylases, proteases and lipases to sugars, amino acids and glycerol.

      • Acetogenesis is an aerobic process that produces short chain fatty acids, usually ethanoic acid. Carbon monoxide and hydrogen gas are produced as the oxygen is used up.

      • Methanogenesis is an anaerobic process which produces methane. The solid material left behind is dried up and used as biofuels or fertilisers.

Biosphere integrity

• The second core boundary, which is also labelled as high risk.

• Species interaction provides ecosystem services, such as carbon dioxide absorption and mineral recycling.

• Human activity has changed the environment too rapidly for natural selection to occur, leading some species to become extinct.

• By 2100, more than half the world’s marine species may become extinct due to ocean pollution.

• Tundra ecosystems are experiencing temperature rises.

• Coral reefs are becoming bleached - the zooxanthellae that gives corals their colour leave due to the heat. They are no longer fed by their photosynthesis.

  • They do not often return even if conditions improve, leaving the corals to die.

• Coastal plains are becoming submerged as the sea levels rise, especially by salt water. This causes water to leave the plants via osmosis, killing them.

  • These communities absorb carbon dioxide 50x more efficiently.

• Biodiversity monitoring is necessary to store gene banks and spread public awareness.

Land-system change

• This is a high risk boundary.

• An example is deforestation for agricultural and urban development reasons.

• This is worsened by the misuse of land decreasing plant yields, therefore more land is required for food.

• Farming needs to be concentrated into more productive areas, and genetically modified plants can be used.

• Meat consumption should also decrease.

Biogeochemical flows

• This is a high risk boundary.

• It refers to the cycling of minerals through biotic and abiotic components of an ecosystem.

  • There are many minerals that have cycles, such as carbon, sulphur, phosphorus and nitrogen.

• These maintain the availability of elements in ions throughout a food web.

• Agricultural fertilisers have been used so intensively that the boundaries for phosphorus have been crossed and are no longer self-sustaining.

• This can cause eutrophication and other pollution caused events.

• To reduce this, the aim has been to transfer nitrogen fixing genes into plants, but this has not been achieved yet.

Stratospheric ozone

• This is a safe boundary.

• The ozone is a layer in the stratosphere, which is 10-50km up. Usually this is in equilibrium with oxygen.

• Halogenated hydrocarbons, such as CFCs (chlorofluorocarbons) alter the position of this equilibrium to favour ozone breakdown.

  • Under UV light, CFCs release chlorine as free radicals and each one can break down 100,000 ozone molecules.

• CFCs were widely used in sprays and manufacture of disposable food containers.

  • Their particles are heavy than air, and therefore take 2-5 years to reach the ozone.

• The ozone depletion they caused was first observed in the 1970s, with the thinning so significant in Antartica a hole was detected each spring.

  • As ozone absorbs UV light, the UV intensity that reaches earth increased. This led to cancer and cataracts increases.

• CFCs were banned in spray cans in 1978, and the Montreal protocols banned CFC manufacture and limited its use in 1987.

• The ozone is continuing to rebuild at present.

Ocean acidification

• This is a safe boundary.

• Ocean pH has decreased from the 17th century from 8.16 to 8.03. This represents a 30% increase in hydrogen ion concentration.

  • This is due to carbon dioxide from the air dissolving in bodies of water to hydrogen carbonate, releasing a hydrogen ion.

• This leaches calcium carbonate out of mollusc, arthropod exoskeletons, and coral shells - softening and leaving them vulnerable.

• Fishes gill structure is also harmed, affecting fish farming.

Freshwater use

• This is a safe boundary.

• The majority of higher plants and mammals require fresh water to live.

• It occurs naturally in ice structures, lakes, rivers, streams and underground sources.

  • It comes from precipitation as mist, rain and snow.

• 2.5% of Earth’s water is fresh, and most of this is frozen in ice sheets.

  • However, this is not always drinkable as it can contaminated by pollution, salt, dust and sand.

• 12% of the global population have no access to safe drinking water, and it is predicted that by 2050 14% will have insufficient water. This is occuring due to:

  • Changing landscapes (Land-system change boundary).

  • Agricultural use of water for plants, which can drain underground resources that cannot be replenished.

  • Increased demand in warmer areas.

  • Water pollution, done by bacteria or human pollution.

  • Climate change via ice caps melting, sea level rises contaminating fresh water and decreased rainfall in arid areas.

  • Increasing life expectancy.

  • Increasing usage, such as daily showers and baths.

• There are many methods to increase this availability:

  • Non-food crops should not be irrigated.

  • Water efficiency - showers>baths.

  • Wastewater reclamation for irrigation and industrial usage.

  • Water capture.

  • Drip irrigation systems reduce water used in irrigation by feeding it directly to the roots instead of spraying.

  • Desalination is used to make salt water drinkable, removing the salt. It has a high energy consumption and can be expensive.

    • Solar stills can be used to avoid fossil fuel usage.

    • Reverse osmosis can be used via a selectively permeable membrane, with pressure applied from the sea water to push water into fresh water.

      • Fossil fuels are often used, however waste heat is used to generate steam to increase efficiency.

    • However, it releases brine (concentrated sodium chloride solution) which requires diluting or it will sink due to the high solute concentration and damages the seabed.

Atmospheric aerosol loading

• This boundary has not been quantified.

• These are microscopic particles put into the atmosphere by fuel combustion and dust creation. Their concentration has doubled since pre-Industrial Revolution.

  • It is released in motor vehicles (especially diesel) and aerosols.

• They can exacerbate respiratory problems, increasing lung cancer, cardiovascular disease and lung diseases.

• It can create layers on plant leaves, reducing photosynthesis.

• Sulphates in aerosols can reflect or absorb and reradiate sunlight.

Introduction of novel entities

• This boundary has not been quantified.

• This encompasses organic pollutants, radioactive materials, nanomaterials and microplastics.

  • Some are so toxic they’ve already been banned, such as CFCs and PCBs.

• They are hard to quantify due to the large amounts and the lack of knowledge on how they interact.