4.1 Climate change Flashcards
What is the Quaternary period
Ice age
how long is the Quaternary period
2.6 millions years ago to present day, in Cenozoic era
What happened during the Pleistocene epoch
- cold glacial episodes, lasting 100,000 years
-Thick ice expanded, covering vast areas of continents, retreated, followed by a warmer interglacial episode - Warmer intervals shorter, lasting 10,000 years
When did the Holocene epoch begin
last glacial expansion ended and current interglacial episode started
What period and epoch do we live in
Quaternary - period
Holocene - epoch
When did the Holocene epoch start
12,000 year ago
What era are we in
Cenozoic
When do the reliable climate change data records produced by the Met Office date back to
1914
What do they use to measure climate change?
satellites, weather stations, weather balloons, radar and ocean buoys
What has increased by 1C over the last 100 years
Earths average surface air temperature
why have sea levels risen
due to thermal expansion and ice sheets melting
What is proxy data
natural recorders to estimate what the climate was, tree rings or fossil pollen
Why was proxy data unreliable
only indicate climate change not direct evidence of accurate temperatures
What do ice cores act like
time capsules, different layers build up over thousands of years
How far do records of ice cores go back too
800,000 years
What can oxygen istopes in ice cores do
estimate the temperatures
What can you see when ice cores are melted
trapped carbon dioxide and methane are released, can be compared to present levels to see the differences between climate then and now
Outline the use of ocean sediments as evidence for climate change
The deeper the sediment the older it is
organisms and remains of plankton reveal information such as past surface water temperatures and levels of oxygen and nutrients
How can paintings and diaries suggest climate change
written observations suggest evidence of crops failing, sea ice preventing ships from landing in Iceland and winter ‘frost fairs’ held on the frozen River Thames.
