4.4 climate change Flashcards
(28 cards)
what is a greenhouse gas
a gas that absorbs longwave radiation, trapping it in the earths atmosphere
when radiation hits the earth, its radiated back as __________ radiation
longwave radiation
(From sun = shortwave)
2 gases that contribute most to greenhosue effect
water vapour and co2
how does water vapour accumulate in the atmosphere?
evaporation from ocean surface + transpiration
how does co2 accumulate in the atmosphere
living organisms respire
organic matter / fossil fuels are burned
2 other greenhouse gases that contribute to greenhouse effect
methane
nitrous oxides
2 sources of methane
methanogenic bacteria — archaeans when the break down organic waste
coal mining – methane deposits released
3 sources of nitrous oxides
fossil fuel combustion
agriculture
activity of some types of bacteria
name the 2 factors affecting the impact of a greenhouse gas
- ability to absorb longwave radiation
- concentration in atmosphere
how does ability to absorb radiation and concentration in atmos of METHANE affect its impact
strong ability to absorb radiation
BUT relatively low atmospheric concentration
2 things that atmospheric concetration of a greenhouse gas depends on
- balance between RELEASE and REMOVAL of that gas from the atmosphere
eg CO2 - length of time gas is present in atmosphere
methane vs water vapour length of time present in atmospher e
methane: remains 10-12 years before being oxidised
water vapour: most abundant gas BUT only 9 days
in what part of the spectrum is the radiation radiated back to the atmosphere by the earth
infra-red – longer wavelength
percentage of radiation absorbed by atmosphere on the way:
1. in
2. out
- 25%
- 85%
impacts of increase in global temps: climate change 3
incr temp = incr water evaporation
= heavier rainfall
affects wind and ocean currents
= stronger hurricanes and typhoons
rising sea levels
impact of warming climates on animals
loss of habitat – coastal, ice
changes to migratory patterns: artic areas warmer = competition
incr decomposition bc melting permafrost = exposes saphotropic bacteria to oxygen, releasing methane
co2 levels have risen to record highs since the __________ ___________
industrial revolution
why did the industrial revolution result in so much co2
increased use of fossil fuels: transport, electricity, heating
clearing and burning of forested land
what is earths main carbon sink
oceans !
thats why co2 levels are lower than what would be expected after the industrial revolution
impact of more co2 absorbed in the oceans
ocean acidification = threathens habitat eg corals
how does heavier rainfall lead to acid rain
more GH gases dissolve into rainwater = falls into land, rivers, lakes, oceans as acid rain
process of ocean acidification 3
- incr CO2 dissolves in water, becoming carbonic acid
- dissociates to become H+ ions
- decr in pH
effect of decr pH on CaCO3
decr pH = incr solubility of calcium carbonate = decr amt available for organisms
why is calcium carbonate importnat in oceans
used by marine organisms (crustaceans, molluscs, corals) to build exoskeletons and shells. – calcification
