Unit 3: climate change Flashcards
Sources of CO2
Burning of fossil fuels –> releases CO2
Deforestation -> releases CO2 in trees -> less trees less CO2 removed
Respiration
Decomposition
Sources of CH4
Produced when bacteria rot organic matter
Livestock farming e.g. cattle -> >30% of US GH gas emissions
Rice Growing
Rubbish in landfills
When fossil fuels are extracted
Wetlands (rotting at swamps and marshes)
Sources of Nitrous Oxides
Vehicles exhaust
Manufacture & use of nitrogen-based chemical fertilizers (released when soil is ploughed/ when rain flows through soil)
Emitted by bacteria in soils and oceans
Sources of CFCs
Aerosol sprays
Foam packaging
Coolants in fridges & air con
Solvents to clean electronic parts
Top 3 contributors of GH gases
Burning of fossil fuels (1st)
Deforestation
Agriculture
Reason for increase of gh gases
Affluence
Lifestyle/ Consumption habits
Agriculture
Industrial activities
Motor vehicles
Consumer products
Natural causes of climate change
Variations in solar output
Volcanic activity
Greenhouse effect
Explain variations in solar output
Sun emits varying amts of solar radiation due to changes in magnetic field (has a cycle of abt 11 yrs)
Increase in magnetic activity -> increase in solar radiation
Sunspots: cooler areas on sun surface -> surrounding area radiates more energy
No. of sunspots increase -> higher solar activity -> temp. Increases
exaplain Volcanic eruptions
Large volumes of CO2, water vapour, sulphur dioxide, dust & ash released into atmosphere
SO2 + H2O -> sulphur-based particles in atmosphere -> with dust & ash reflect solar energy back to space -> global dimming -> temporarily cools earth
Explain greenhouse effect
Gases trap longwave radiation emitted from earth’s surface -> warming atmosphere
Earth receives shortwave radiation in the form of visible light -> absorbed by earth’s surface -> heats up
Manmade causes of climate change
Changing land use (industrialization, urbanization, agriculture)
Buring fossil fuels
Deforestation
explain ways to guard against sea level rise
Retreat from shoreline
Flood proof structures (truckng dirt into land before building, elevate occupid floors above flood level, seawalls, sandbags, natural barriers)
Build levees
(Dirt, rock, concrete can be effective barriers
Expensive and can fail)
Restore nature
Natural habitats such as marshes, sandbars and creek beds absorb the energy of storms
Past development has tended to erase or bury these features, but recent restoration projects are changing that
Methods SG uses to mitigate climate change
Protection
MRT stations built with elevated entrances
New developments built at least 4 metres above mean sea level
Critical infrastructure (e.g. airport) built at least 5 metres above mean sea level
Building
2nd pump house built at Marina Barrage
Engineering solutions explored e.g. seawalls
Managing costs
Plans progressive and flexible to adapt to how global warming progresses
Cost $100 billion or more to be spread over 50 to 100 yrs -> can afford & be ready when needed
