Icehouse Climates
Abstract Over the past 1,000 million years, Earth’s climate oscillated between warm greenhouse climates (abundant CO2), when sea level was high, and cold icehouse climates (low CO2), when sea level was low and large ice sheets were common. At times between 1,000 and 500 million years ago Earth was a...
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| Format: | Book Part |
| Language: | English |
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Oxford University PressNew York
2023
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| Online Access: | http://dx.doi.org/10.1093/oso/9780197627983.003.0002 https://academic.oup.com/book/chapter-pdf/58047736/oso-9780197627983-chapter-2.pdf |
| Summary: | Abstract Over the past 1,000 million years, Earth’s climate oscillated between warm greenhouse climates (abundant CO2), when sea level was high, and cold icehouse climates (low CO2), when sea level was low and large ice sheets were common. At times between 1,000 and 500 million years ago Earth was a “snowball” covered in ice from poles to tropics. Icehouse climates with polar ice developed around 445 million years ago, 300 million years ago, and over the past 34 million years (when the Antarctic ice sheet formed). Northern hemisphere ice sheets developed over the past 2.6 million years, when climates oscillated from warm to cold in Milankovitch Cycles. Human civilization developed in a warm Milankovitch Cycle peaking about 12,000 years ago. Plate tectonics drove rises in CO2 when volcanism was abundant. Chemical weathering of mountains drove falls in CO2. As trees evolved, they also sucked CO2 out of the air. |
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