Human Impact

• what are the 9 planetary boundaries? - climate change- biodiversity- land use boundary- biogeochemical cycles/nitrogen- ozone- ocean acidification- freshwater-aerosol-novel entities
• climate change caused by: -green house gas levels rising from burning of fossil fuels, deforestationconsequence:- global warming- impacts on rainfall, wind patterns, ocean currents- melting of icecapsremedial measures:- stop burning fossil fuels- reduce deforestation
• biodiversity cause:- habitat destructionconsequence:- human caused environmental change occurs too quickly and species cannot evolve quickly enough to adapt- reduction in species numberremedial measures:- monitor biodiversity- species conservations - sperm/seed banks- education
• ocean acidification  cause:- greenhouse gases from burning fossil fuels and CO2 levels-CO2 in seawater forming carbonic acid increasing acidityconsequence:- low ph cause calcium carbonate to leach out of corals, shells of molluscs etc.remedial measures:- reduce CO2 levels by reducing fossil fuel use and deforestation
• land use change  cause:- deforestation for food and biofuel productionconsequence:- production of biofuel crops and those grown for export means insufficient food crops for local use - reduced biodiversityremedial measures:- concentrte farming in most productive areas- reduce meat consumption- more efficient crops
• nitrate and phosphate cause:- use of fertilisers containing nitrate and phosphateconsequence:- eutrophication from nitrate and phosphate run off into bodies of waterremedial measures:- reduce use of fertilisers
• ozone cause:- manufacture and use of chlorinated fluorocarbons in aerosols, refridgerator coolants etc.consequence:- ozone layer destruction to “hole” in ozone layer- harmful UV rays not absorbed increasing risk of skin cancerremedial measures:- manufacture of chlorinated fluorocarbons were banned
• freshwater use cause:- increased water use for irrigation and industry - climate change- pollution of water- change in land useconsequence:- reduction in freshwater availabilityremedial measures:- stop irrigation for non-food crops- use desalinated water
• aerosol cause:- atmosphere contains minute particles such as ash and soot from combustion and coal power stations, dust from constructionconsequence:- increased respiratory problems and lung cancers- can build up on leaves and reduce photosynthesis
• novel entities - inorganic pollutants which may be persistent and have irreversible effects- includes synthetic organic pollutantsconsequence:- bioaccumulation in food chains remedial measures:some are already controlled by use of DDT is banned
• what is extinction? results in a loss of species and a decrease in biodiversity
• what is an endangered species? species that is at a serious risk of extinction
• possible reasons for species becoming endangered due to human impact? - destroying habitats e.g. removing hedges, deforestation- pollution of the environment e.g. pesticides- introduction of new species to an ecosystem, might outcompete native species for food and space- introduction of new species might carry diseases that affect native populations- building roads, houses, factories
• what is convervation? involves creation, management and protection of habitats.
• ways in which conservation may be achieved? - habitat protection by nature reserves- legislations to prevent overfishing, poaching, collecting birds’ eggs and picking wild flowers- breeding programmes by zoos and botanic gardens- sperm banks and seed stores- reintroduction programmes such as the red kite in mid wales- pollution control
• what are gene pools? the alleles present in a population
• how can gene pools be conserved? via in-situ or ex-situ methods of conservation?
• what is ex-situ conservation? - conservation outside of an organism’s habitat e.g. seed banks
• advantages of ex-situ methods of conservation? - can be rapid to prevent extinction and maintain genetic diversity- can be used for scientific research and education- can be used to rapidly increase numbers- seed banks take up less room than growing in fields
• disadvantages of ex-situ methods of conservation? - reintroduction can be difficult, habitat may have evolved without the organism- breeding programmes are expensive and difficult- seed banks cannot store every kind of seed- seeds dont last forever- can reduce wild populations
• what is in-situ conservation? conservation of whole habitats e.g. SSI (areas of specific scientific interest)
• what is sustainability? going about something in a way that minimises damage to environment
• advantages of in situ conservation? - recover viable populations in their native habitats- protects biodiversity- protects representative examples of ecosystems
• disadvantages of in-situ conservation? - risks dramatic decrease in genetic diversity if unsuccessful - may not remove the problem e.g. disease
• how does overfishing threaten sustainability of fish populations? - too much fishing means that numbers within a population cannot be maintained
• how can we reduce the impact of overfishing? fishing quotas - limit how many members of one species can be caughtreducing size of fishing fleets - fewer boats are out catching fish- restricting mesh sizes for fishing nets - smaller mesh sizes can catch more fish so having a minimum mesh size means smaller fish can escape-exclusion zones - banning fishing from some zones
• what is fish farming? isolating an area of the sea for the purpose of breeding and growing fish in managed conditions
• how can fish farming lead to problems in aquatic ecosystems? - provision of additional nutrients can lead to excess nutrients in the area leaking out and leading to eutrophication- overuse of antibiotics can lead to resistance in pathogenic bacteria- non-specific pesticides can leak out, affecting marine food chains- fish in netted-off areas can be overcrowded - diseases and pests can spread easily
• what are planetary boundaries? define the safe operating space for humanity, if one of more of these thresholds are exceeded there is the possibility of abrupt and irreversible environmental change