455lec1 - Earth History and Env Problems Earth history is...

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Earth History and Env Problems Earth history is essential to understand our place in time and space Scientific issues: BASELINE data on how the Earth “naturally” behaves: How often does global warming occur? How “warm” is “warm”? How often do extinctions occur? Time also raises ETHICAL issues: generational debt, rights of future individuals
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Geologic Time (Deep Time) This is a humbling perspective, in a culture with a short-term view! Until the 1800’s most people thought the Earth was only a few thousand years old (from Biblical “begats”) They also thought the Earth was the center of the Universe until the 1800’s We now know the sun is only one of trillions of stars and we live far from the center of our own galaxy
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SPACE TIME What we are concerned with “Discounting the future”: 1) would you pay $500 to solve global warming 100 yr from now? NO 2) would you pay $500 to solve global warming next yr? YES
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“Hadean” is name given to Eon in which Earth formed by accretion and meteorite bombardment. It was truly “hell on earth” as constant meteorite bombardment and high interior heat flow combined to keep early Earth surface in nearly constant molten state. Atmosphere of early Earth likely reducing (i.e. no oxygen) and similar to present Jupiter atmosphere (?), mostly: methane (CH4), ammonia (NH3), hydrogen (H2) and helium (He) with some traces of noble gases like neon (Ne) http://www.carleton.ca/%7Etpatters/teaching/intro/intro.html
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Calendar Year Metaphor •January 1 →Earth forms •January and early February →Earth organized into core, mantle, and crust •February 21 →Life evolves •October 25 →Complex organisms, including those with shells and hard parts, evolve •December 7 →Reptiles evolve •December 25 →Dinosaurs become extinct (50% of
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455lec1 - Earth History and Env Problems Earth history is...

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