Download Fossil Record: Climate Change

Fossil Record: Climate Change
Captivate Script Lesson 3
Title Slide: Fossil Record: Climate Change
Slide 2: What is Climate Change?
First, Climate is the long-term averages and variations in weather.
So, Climate change is changes in the otherwise expected weather.
Paleoclimatologists are scientists who study patterns of past global climate
Slide 3: Palaeoclimatology
Is the study of past climates and climate change prior to the use of instruments.
•It Does not use observations of temperature, rainfall and other climatic variables
•Instead paleoclimatology sses records of natural phenomena that are caused by climate
•This process has allowed scientists to reconstruct climate of last 500 million years
Slide 4: Four Common Records
To reconstruct paleoclimates, four types of records are analyzed:
•Historical Records: including ancient inscriptions, scientific writings, diaries, etc.
•Biological Records: such as Tree Rings, stomata from plant leaves
•Glaciological Records: which involves Ice Cores
•Geological Records: which includes both Sea Sediments and Rock Strata.
Slide 5: Ice Cores and Sea Sediments
Paleoclimatologists use the data gathered from ice cores and sea sediments to reconstruct time
frames that are over hundreds of thousands of years old.
This data is believed to be fairly reliable and consistent.
Slide 6: Ice Cores
Ice cores have been collected from Antarctica and Greenland. Some ice cores are kilometers long.
These cores contain evidence of the composition of the atmosphere that existed thousands of years
ago.
This, in turn, provides information on the climate of those periods.
Slide 7: Sea Sediment
Both organic and inorganic Sea sediments are analyzed to gather information on climate change.
•An example of organic sediment is the remnants of microscopic plankton
•An example of inorganic sediment is materials that have eroded from land masses-rock, dust, soil,
etc.
Slide 8: Sea Sediments
•Deep-sea sediments contain microscopic fossils of marine animals, volcanic glass, sands and
minerals originally from land.
•The microscopic fossils are important as time and environmental indicators.
•They are very sensitive to slight changes in temperature and chemical changes in their
environment.
Slide 9: Other indicators of Climate Change
The La Brea Tar Pits is another example of fossils being used to determine past climate changes.
•Microfossils located here, including freshwater shells and small animal bones are used by
paleclimatologists to determine the environment and climate of the area 40,000 years ago.
Slide 10: La Brea Tar Pits
The fossil record also includes wood, leaves, cones, and seeds.
Plant fossils are excellent indicators of weather during that time period.
Scientists use this evidence to determine the Pleistocene climate of Los Angeles was not drastically
different from the present day climate.
Slide 11: Climate Changes
Palaeoclimatologists have mapped out the last 500 million years of climate.
Their recorded data shows that the global climate has moved from extensive periods of global
warmth to periods of global cold several times, each lasting 100 million years or more.