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Chapter 4 Book Notes

What regulates earths climate most of the earths co2

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What regulates Earth’s climate? Most of the Earth’s CO2 is locked up in carbonate rocks, sedimentary rocks such as limestone that are rich in carbon and oxygen If Earth’s carbon dioxide were in our atmosphere rather than in carbonate rocks, our planet would be nearly as hot as Venus and uninhabitable The mechanism by which CO2 has been removed from Earth’s atmosphere and by which the current small amount of atmospheric CO2 remains stable is called the inorganic carbon dioxide cycle Earth has so little CO2 in its atmosphere because most of the CO2 was dissolved in the oceans, where chemical reactions converted it to carbonate minerals
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Feedback processes: processes in which a change in one property amplifies (positive feedback) or counteracts (negative feedback) the behavior of the rest of the system Conclusion: The natural thermostat of the CO2 cycle has allowed the greenhouse effect to strengthen or weaken just enough to keep Earth’s climate in a range that has allowed for liquid water, regardless of what other changes have occurred on our planet. How does Earth’s climate change over long periods of time? Ice ages occur when the global average temperature drops by a few degrees Greater tilt means more extreme seasons With less sunlight being absorbed, surface cools, which in turn allows the oceans to freeze further (Snowball Earth) Strengthening greenhouse effect would have warmed Earth enough to start melting ocean surface ice Conclusion: The regulatory mechanism sometimes breaks down, leading to periods such as the Snowball Earth episodes, but the CO2 cycle ultimately brings the climate back into balance. How did the giant impact model win out over competing models? First model: held that the Moon formed along with Earth through the same process of accretion (two worlds born together) Second model: suggested that the Moon had been an independent “planet” orbiting the Sun that was somehow captured into Earth’s orbit Third model: suggested that a young, molten Earth had been spinning so rapidly that it split into two pieces, casting off the piece that became the Moon The Moon rocks contained virtually no volatile , or easily vaporized, ingredients The Moon was made from material that accreted in Earth orbit after first being violently blasted out of Earth’s mantle Mars-sized object blasted into young Earth Blast shattered and melted our planet, splashing out molten debris from the mantle Conclusion: Much of the material fell back to Earth, but some remained in orbit. There, with its volatile content having vaporized and escaped, the material accreted to make the moon. Does the giant impact model count as science? It is natural and testable, and we can imagine future discoveries that would cause us to call it into question
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What regulates Earths climate Most of the Earths CO2 is...

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