human influences on the environment Flashcards
(21 cards)
what does sulfur dioxide do (2)
- combines with water to form acid rain
- causes respiratory problems in humans
what does carbon monoxide do (2)
- binds to haemoglobin on red blood cells, reducing the oxygen capacity of them
- which can lead to suffocation and death
what is a greenhouse gas
a gas which absorbs infrared radiation from the sun and causes temperatures to rise
what are the 5 greenhouse gases
- carbon dioxide
- methane
- water vapour
- nitrous oxides
- CFCs
when is carbon dioxide produced
in the combustion of fossil fuels
when is methane produced
by cattle as they digest grass & released by rise paddy fields
what is the enhanced greenhouse effect
when increasing levels of greenhouse gasses from human activities cause the earth’s temperature to rise above normal, leading to global warming
how does the enhanced greenhouse effect happen
- sun emits rays which enter the earth’s atmosphere
- heat bounces back from the surface
- some heat is reflected back into space
- some heat is absorbed by greenhouses and trapped within the earths atmosphere
consequences of greenhouse effect (5)
- ocean temperature’s rise
- increasing temperatures
- loss of habitats
- decrease in biodiversity
- increased specie migration
why is it bad if ocean temperature’s rise
they cause rising sea levels and melting polar ice caps
why is bad if temperatures increase
they cause extreme storms, droughts and floods
why is decrease in biodiversity bad
food chains are disrupted
why is increased specie migration bad
spread of pathogens and disease
what is eutrophication
minerals from agricultural fertilisers can be leached into water bodies resulting in eutrophication
process of eutrophication
1- fertilisers are high in nitrogen and cause growth, resulting in overgrowth of aquatic plants & algae at water’s surface
2- aquatic plants below the surface die and get decomposed. by decomposers
3- decomposers increase in numbers meaning increased respiration which uses up oxygen, reducing oxygen levels
4- water doesn’t contain enough oxygen to support other organisms, so many die
effects of sewage pollution (3)
- aquatic organisms dependant on oxygen die
- aquatic ecosystems decrease in biodiversity
- this leads to increase in pathogenic bacteria
effects of deforestation (4)
Leaching
Soil erosion
Water cycle disturbance
Carbon cycle disturbance + global warming
how does deforestation cause leaching
soil minerals washed away by rain into water bodies
how does deforestation cause soil erosion
tree roots don’t hold soil together, so more likely to be washed or blown away
how does deforestation cause disturbance of water cycle
removal of trees reduce the release of water vapour into the atmosphere by transpiration, so less clouds and rainfall
how does deforestation cause disturbance of carbon cycle and global warming (2)
the removal of trees means less photosynthesis, so less carbon removed from atmosphere.
The combustion of cut down trees increases the release of CO2 into the atmosphere
