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Published byAugusta Holt Modified over 9 years ago
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Why should a geologist be studying climate?
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What defines INTERVALS on geologic timescale?
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What defines BOUNDARIES on geologic timescale?
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What causes ALL mass extinction events?
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CLIMATE CHANGE is responsible for the organization of the geologic timescale
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What are the (non-human) drivers of climate change?
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What do these striations result from?
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Would glacial striations form in an environment like this?
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Glacial remnants in Africa are explained by: 1) plate tectonics
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Where do you find palm fronds today? Fossil palm frond
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Where do you find palm fronds today? Hawaii
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Bahamas
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Wyoming?
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Where would you expect to find alligators today?
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Everglades
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China
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Ellesmere Island?
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Alligator fossils found on Ellesmere Island 78° North (north of Greenland) 54.8-33.7 Mya Eocene Ellesmere Island?
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Fossil palm fronds from Eocene (54.8-33.7 Mya) in Wyoming Did plate tectonics cause this?
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Have the positions of Wyoming and Ellesmere changed much over the last 40 Mya?
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Fossil palm fronds from Eocene (54.8-33.7 Mya) in Wyoming NOT caused by plate tectonics
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What was going on here to change global temperature? Could we have alligators in the Arctic again?
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What else besides plate tectonics can cause climate changes over long timescales?
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2) Solar Forcing Variability
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What causes the “eccentricity” of Earth’s orbit
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Gravitational interactions with the orbits of Jupiter and Saturn
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What is the period of Earth’s eccentricity?
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What familiar climate phenomenon does Earth’s “obliquity” cause?
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Seasonality results from Earth’s obliquity
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What is the period of Earth’s obliquity?
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“Precession” of the equinoxes occurs due to tidal forces from Sun and Moon
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What is the period of Earth’s precession?
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Combined solar forcing is known as “Milankovitch cycles” 1920
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Deep sea sediments record Milankovitch cycles over 500 Kya
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Milankovitch cycles influence glacial cycles
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How have glacial cycles changed over last 1000 Kya?
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What else besides: 1)plate tectonics 2)orbital changes 3)…? can cause natural climate changes?
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3) Variations in solar intensity …sunpot activity
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NATURAL causes of global climate change: 1)plate tectonics 2)orbital changes 3)solar intensity
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Earth’s climate system has great complexity
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Earth’s Climate Components Simplified 5-part system
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Earth’s Climate Components – Simplified Cause and Effect ~ “Forcing and Response” 1 2 3
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Earth’s Climate Components – The Human Factor 1 2 3 4
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Forcing: Factors that drive or cause change.
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Forcing: Factors that drive or cause change. Response: A system reacting to a change in forcing.
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Forcing: Factors that drive or cause change. Response: A system reacting to a change in forcing. Lag Time: The time it takes a system to react completely to a change in forcing.
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Speed of Forcing Speed of Response How quickly does climate react?
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Speed of Forcing Speed of Response 100’s of millions of yrs 40,000- 100,000 yrs 10,000s of yrs Decades to Centuries Hours to Weeks Hours to 10,000 yrs Hours to Centuries Days to 1,500 yrs Hours to Months?????????
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Forcing Response 100’s of millions of yrs 40,000- 100,000 yrs 10,000s of yrs Decades to Centuries Hours to Weeks Hours to 10,000 yrs Hours to Centuries Days to 1,500 yrs Hours to Months?????????
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