Determining Earth's conditions in the past - Proxy Data
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Historical written records
newspapers, diary entries, ships’ logs ‘ thousands of years bias/subjective
Coral
made of calcium carbonate density of reef changes depending on the availability of carbon (dissolved from the atmosphere) only grow in certain areas destroyed in acidic conditions
Pollen
determine which plant/species it came from certain plants are associated with certain climates there are no flowering plants in some areas
Ice cores
date back hundreds of thousands of years builds up layers annually (thick = wet+warm) analysis of trapped (greenhouse) gases oxygen isotope analysis - O18 isotope is heavier meaning H2O molecules require more energy to evaporate - hotter years = more precipitated and preserved
Tree rings (dendrochronology)
one per year wider and lighter= warmer+wetter years date back few thousand years preserved as fossilised remains not all trees have rings trees don’t grow everywhere
Ocean and Lake sediments
certain plants are associated with certain climates find fossils and their origin
What are the limitations of proxy data?
subjective does not date back very far unless fossilised only collects data from certain areas damaging to collect data
What data collection methods do we use today?
weather stations weather balloon thermometer satellites - measure ice/cloud cover - weather systems anemometer - wind speed rain gauge
What methods do we use to collect atmospheric data?
temp - thermometer air pressure - barometer humidity - hygrometer wind speed - anemometer
What methods do we use to collect data on land?
temp - thermometer precipitation - rain gauge migration - living organisms
What methods do we use to collect data from oceans/what data do we collect?
temp - thermometer sea levels ocean acidity species distribution salinity ocean currents
What information can we collect from space?
cloud cover ice cover number/movement of weather systems colour of oceans - algal blooms monitor species - movement+distribution
Pros of modern methods
more advanced collects data from across the whole planet more accurate
Cons of modern methods
short history invasion of privacy expensive
Pros of proxy methods
more data to compare
Cons of proxy methods
subjective only collects data from specific areas damaging to obtain data