Evidence of Climate Change
- Created by: Hayley Petts
- Created on: 07-01-13 21:05
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- Evidence of Climate change
- Long Term
- Oxygen Isotopes
- sampled from ice and sediment cores
- ration of oxygen 16 to 18 is a good indicator of past sea levels
- ice from glacial periods are enriched with oxygen 16
- Ice cores - CO2 levels
- bubbles trapped
- levels have varied between 190 ppm - 280 over last 800,000 years
- made up of layers - one layer formed every year
- can use different layers to detect temperaturefor different years
- Sea Level Change
- affected by volume of water stored as ice
- past sea levels shown by raised beaches
- Oxygen Isotopes
- Medium Term
- Pollen Analysis
- pollen from plants often reserved in sediments
- found in peat bogs
- can be identified and dated to when it was released
- compare conditions that plants live in now with back then
- pollen from plants often reserved in sediments
- Tree Rings
- new tree ring formed each year
- thick ring = good conditions
- scientists can take cores and find the age of the tree from the rings
- can reliably show climate change from 10,000 years ago
- Retreating Glaciers
- can be tracked by paintings, direct measurements, and photographs
- can tell how big glacier was from how far it extended
- looking at position of rocks deposited
- if glacier is miles away from rocks indicates climate change
- Pollen Analysis
- Short Term
- Weather records
- consistently be collected since 1861
- used to show climate change over short period of time
- Polar Ice Melt
- melting of Greenland ice sheet has increased by 16% since 1979
- increased melting shows increased temperatures
- Ecosystem Changes
- changes in temperature affect availability of food and shelter
- affect what species live in area
- can be used to show climate change
- changes in temperature affect availability of food and shelter
- Weather records
- Long Term
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