climate
the average pattern of elements of weather prevailing in an area over a long period of time
30 years +
climate change
an alteration of the climate system over an extended period
main greenhouse gases
- ozone (O3)
- methane (CH4)
- carbon dioxide (CO2)
- water vapour (H2O)
- sulphur dioxide (SO2)
- nitrous oxides
- CFCs and HFCs
these gases damage the ozone layer which protects us from UV radiation
physical causes of climate change
- volcanoes
- sun spot activity
- eccentricity (stretch)
- axial obliquity (tilt)
- melting permafrost
- fumeroles
- melting ice
volcanoes
physical causes of climate change
- volcanoes emit gases (e.g. CO2) which contribute to greenhouse effect
- sulphur dioxide from volcanoes combines with oxygen and water in the stratosphere to form sulphuric acid which condenses to form sulphate aerosole droplets. the droplets form a haze blocking out solar energy causing cooling
- large amounts of ash and dust stops the sun’s energy reaching earth causing cooling
sun spot activity
physical causes of climate change
- sunspots appear on the sun when additional solar energy is being released
- high sunspot activity result in warming
11 year cycles
eccentricity
physical causes of climate change
- earths orbit becomes more elliptical
- this means the amount of energy received varies depending on the earth’s distance from the sun
97,000 year cycle
axial obliquity
physical causes of climate change
- the angle of the earth’s axis changes meaning that the poles are tilted more towards the sun and receive more solar energy
41,000 year cycle
melting permafrost
physical causes of climate change
- during summer in the arctic the top layer of earth defrosts and becomes marshy as permafrost prevents drainage of water
- vegetation therefore decays releasing methane, contibuting to the greenhouse effect, causing warming
every year
fumeroles
physical causes of climate change
- these vents release gases (CO2, hydrogen sulphate, hydrogen chloride) which absorb solar energy, warming our planet
melting ice
physical causes of climate change
- melting ice releases freshwater into the oceans
- this can lead to changes in ocean circulation and reduce the albedo effect so earth absorbs rather than reflects
albedo effect
a measure of how reflective a surface is
ice and snow has high albedo, dark soils and forests have low albedo
carbon dioxide
human causes of climate change
- burning fossil fuels
- icreased car ownership
- deforestation
- peat bog reclaimation
- increased air travel
methane
human causes of climate change
- landfill (decaying waste)
- padi fields (rice production)
- cattle farming (animal feces)
20 times more effective at trapping heat than CO2
nitrous oxides
human causes of climate change
- more cars (exhaust emissions)
- power stations (burning fossil fuels)
- fertilisers
200 - 300 times more effective at trapping heat than CO2
CFCs (chlorofluorocarbons)
human causes of climate change
- incorrect disposal of old fridges releases CFCs when the foam insulation is shredded
17,700 times more effective at trapping heat than CO2
local effects of climate change
- increased average rainfall
- increased annual temperatures
- rising sea levels
increased average rainfall
local impacts of climate change
social
- flooding damages homes
- insurance of homes go up
- strains emergency services
economic
- money spent on flood defence
- tourism will go down
environmental
- salmon spawning grounds are destroyed as the gravels are washed away
increased annual temperatures
local impacts of climate change
social
- heat waves kill the young and elderly with medical conditions, straining healthcare
economic
- longer growing season increases crop yield
- traditional crops do not grow as well
- tourists are attracted to warmer beaches boosting local economy
environmental
- misquitoes migrate north leading to greater malaria exposure
- increased insecticide use damages environment
- decline in arctic animals
- migration of butterflly species
rising sea levels
local impacts of climate change
social
- coastal erosion leads to destiction of houses and displacement of people
economic
- coastal sea defences need to be built, which costs lots of money
environmental
- coastal erosion leads to loss of habitat and SSSIs
- loss of marshes reduces habitats
global impacts of climate change
- sea level rise - coastal flooding
- extreme weather (such as hurricanes due to warmer seas) - displaces people
- drought - reduces crop yield (famine), environmental refugees (strain resources on receiver), conflict over water supplies
- flooding - displaces people
- disease - malaria, waterborn disease after floods
- ecosystems, habitats and species are disrupted - coral bleaching, ocean acidification, habitat loss leads to extinction
- forest fires - due to prolonged dry spells e.g. australian bush fires
local and national
management strategies for climate change (strategy & limitations)
- promotion of energy efficient products - small impact
- low emission vehicles - expensive, need charged often, limits to public transport
- renewable energy - intermittant, expensive
- afforestation e.g. Africa’s Great Green Wall - trees need time to grow, growing population needs more agricultural land
- reduce meat in diet e.g Veganuary - hard to change cultures attitude to diet, products come from abroad
international
management strategies for climate change (strategy & limitations)
- paris agreement; below 2ºC, report back 5 years - aim rather than commitment
- COP26; net 0, mobilise finance, protect ecosystems, collaborate - not all countries signed agreement
other
management strategies for climate change
- sea defences (thames flood barrier)
- build embankments/levees
