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Flashcards in Internal Controls Deck (27)
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what are 4 IPCC predictions for end of 2100

warmer and wetter +3

>400 ppm atm co2 conc

reduced icesheets

higher sea level


what other era closely represents our current era?

Pliocene 3 mill yrs ago

similar fauna and flora eg africa

same co2 conc 390ppmv


how was the pliocene different to us today?

temps were 3 degrees warmer

sea level 25m higher


name 3 external climate controls

solar variability eg intensity

orbital forcing / gravitational forces eg tides

cosmic material eg meteroties


name 4 internal controls

green house gases - natural or human

global ocean circ - salinity

orography - veg/albedo

tectonic uplift


name a natural greenhouse gas contrubuter

volcanic eruptions

pump out co2 and methane

ash/mud reduces solar radiation


describe the global carbon cycle in terrestrial area

plants respire and photosynthesise.

take in co2 and water (light) and create glucose and o2.

co2 stores in soil

microbian respiration which releases co2

fossil carbon locked underground for many years


describe global carbon cycle in ocean

photosynethesis in upper part of ocean

huge store of carbon

organisms die and sink to bottom locking up carbon

respiration and decompositoon


define biological pump

marine carbon pump
sequestration of carbon from atmosphere and land runoff to ocean interior and seafloor sediments


define vertical deep mixing

warm water on oceans surface currents are carried from low latitudes to high latitudes.

water cools and becomes more dense so they sink


describe the fast carbon cycle

photosynthesis - take in co2
higher photosynethesis in summer months so less co2 present on earth this time

winter when few plants are growing and many are decaying then co2 conc increase

seasonational variations
lowest co2 in august and highest in december


describe the slow carbon cycle

transfer to oceans

deposition of carbon compounds to ocean floor

ocean sediments to carbon rich rock

carbon rock to tectonic margins

carbon compounds released back to atmopshere from volcanic eruptions and uplift of land


how slow is slow carbon cycle

tens and hundreds of millions of years


how much do oceans cover earth



How much more co2 does ocean store than biosphere



why is there highs and lows of methae and co2 in ocean

hypothesis -
interglacial and glacial periods

biological pump - more algae in colder waters so higher intake of co2


describe process of chemical weathering

water and carbon from a weak carbonic acid

acid dissolved rocks and releases calcium/ potassium/ sodium ions and magnesium

they enter ocean where calcium ions combibe with bicarbonate ions to form calcium carbonate

this is controlled by tectonic uplift of mountains


how many big gyres are there



what controls the gyres

global wind patterns

earths rotation

earths landmasses

the coriolus force changes or deflects direction of wind driven currents


what is the ocean deepwater and thermohaline circulation driven by

water density
which is contolled by temp and salinity


what is the thermohaline circulation

driven by global density gradients created by surface heat and freshwater fluxes

travels polewards from equatorial Atlantic region and cools sinking


what is the Atlantic meridional overturning circulation

current in atlantic ocean

characterised by northward flows of warm salty water to upper layers and southward flow of colder deep waters that part of thermohaline circulation

cools to 2-4 degrees / high salinity which sinks down


what is the global conveyor belt

circulation system in ocean

forms thermohaline currents that are driven by density

flows from warm surface currents to cold deep currents

warm waters cools and sinks and cold water warms and rises

takes 1,000 years to complete full cycle


give an example of the global conveyor belt

north atlantic deep water

warm gulf stream moves to norweigian sea and cools to 2-4 degrees, high salinity - it sinks and


what is the modern circumpoalr current in antarctica?

antarctica is isolated due to this current making the island very cold

the current flows throguh 2 gateways at S america and Australia

in the past these gateways were closed - but opened during eocene-oligocene transition 34 mill yrs ago


when did s america gateway open

drake passage

35 mill yrs ago


when did australia gate way open

austrlia tasman antarctica passage

50 mill yrs ago