planetary boundaries Flashcards
define planetary boundaries
safe operating space for humanity
once human activity has passed certain thresholds (planetary boundaries), there is a risk of ‘irreversible and abrupt environmental change
how many planetary boundaries are there?
nine
which planetary boundaries have been crossed?
biodiversity
climate change
nitrogen
land use
which planetary boundaries are avoidable?
fresh water
ocean acidification
ozone boundary
which planetary boundaries are unquantified?
chemical pollution
aerosol boundary
biodiversity - planetary boundary
human activity –> environmental changes too fast for natural selection to produce organisms that adapt to changes and many species have become extinct
changes in habitat –> reduction in biodiversity in regions like tundra (increase in temperature) and marine environments (pollution with oil, acid and sewage)
coral reef bleaching and costal plain submersion –> rising sea levels, reducing biodiversity
climate change - planetary boundary
greenhouse gases are continually being added to the atmosphere
causing an increase in global temperature, climate change, rise in sea levels
nitrogen - planetary boundary
denitrification due to waterlogged soils
use of agricultural fertilisers leading to eutrophication
land use - planetary boundary
deforestation –> farming and urban development has led to a conflict between the need to grow food and the need to grow biofuels and protect natural habitats
fresh water - planetary boundary
organisms need fresh water to live
crossed if do not have enough fresh water to survive
2.5% of water is still fresh
important as it only contains a low concentration of dissolved salts
decrease in supply of freshwater is due to changing landscapes, agriculture, increased demand from humans, water pollution and climate change
ocean acidification - planetary boundary
pH of the oceans is decreasing –> dissolving carbon dioxide forming carbonic acid –> releasing hydrogen ions
low pH –> mollusc, coral shells and arthropod exoskeletons softening, making them vulnerable
gill structure in fish is also affected by low pH and their functioning is damaged
ozone - planetary boundary
chloro-fluorocarbons (CFCs) favour the breakdown of the ozone
CFCs were widely used in spray cans, solvents, refrigerator coolants and manufacture of food and drink containers
resulted in the thinning and development of a ‘hole’ in the ozone layer
use of CFCs in spray cans was banned in 1978
ozone layer is now recovering naturally
chemical pollution - planetary boundary
organic pollutants, radioactive materials, nanomaterials and micro-plastics
could all interact with each other and produce harmful effects
variable we cannot suggest a boundary
aerosol - planetary boundary
atmospheric aerosols are the microscopic particles put into the atmosphere by combustion of fuels and by creating dust from digging and quarrying
sulphates in aerosols reflect sunlight, providing a cooling effect, but other particulates reradiate it, increasing warming
can lead to respiratory problems and cause death from lung disease
what can we do to help biodiversity - planetary boundary
monitoring biodiversity
collecting materials for gene banks
raising public awareness
reduce human behaviour that has generated biodiversity loss
what can we do to reduce climate change - planetary boundary
production of biofuels – these fuels are made by biological processes
growth of biofuel crops takes in carbon dioxide from the atmosphere, the release of carbon dioxide when they’re burnt has less impact – carbon neutral
biofuels can be made by anaerobic digestion of plant material
what can we do to help nitrogen - planetary boundary
planting fields of legumes to increase nitrogen fixation
ploughing soil to improve aeration
prevent anaerobic conditions
what can we do to help land use - planetary boundary
changing farming practices to concentrate it in the most productive areas
reducing consumption of meat would reduce land being cultivated
what can we do to help fresh water - planetary boundary
water conservation (not irrigating non-food crops)
water efficiency
waste water reclamation
drip irrigation systems
desalination is an important technology that removes minerals from salt water to produce fresh water
what can we do to help ocean acidification - planetary boundary
reduction in the burning of fossil fuels
