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Global Warming Or Climate Hysteria?. The Long View The Earth has repeatedly experienced climate change throughout its long history The Earth has repeatedly.

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Presentation on theme: "Global Warming Or Climate Hysteria?. The Long View The Earth has repeatedly experienced climate change throughout its long history The Earth has repeatedly."— Presentation transcript:

1 Global Warming Or Climate Hysteria?

2 The Long View The Earth has repeatedly experienced climate change throughout its long history The Earth has repeatedly experienced climate change throughout its long history The Phanerozoic Eon is characterized by fluctuations between Greenhouse and Icehouse climates. The Phanerozoic Eon is characterized by fluctuations between Greenhouse and Icehouse climates.

3 Greenhouse World Cretaceous Period was one of significant warmth. Cretaceous Period was one of significant warmth. Tropical temperatures not much different. Tropical temperatures not much different. Much warmer at poles – no ice! Much warmer at poles – no ice! Current models cannot duplicate these conditions. Current models cannot duplicate these conditions.

4 The Great Cooling The bottom water of the ocean has cooled gradually – but dramatically over the past 100 million years. The bottom water of the ocean has cooled gradually – but dramatically over the past 100 million years. The Eocene Climatic Optimum

5 The Eocene Climatic Optimum Tropical fossils found at high latitude. Tropical fossils found at high latitude. Fossil forest sites on Axel Heiberg Island, NWT, Canada Fossil forest sites on Axel Heiberg Island, NWT, Canada Turtles, Crocodiles and other fauna excavated from nearby Ellesmere Island Turtles, Crocodiles and other fauna excavated from nearby Ellesmere Island

6 The Eocene Climatic Optimum Tropical fossils found at high latitude. Tropical fossils found at high latitude. Fossil forest sites on Axel Heiberg Island, NWT, Canada Fossil forest sites on Axel Heiberg Island, NWT, Canada Turtles, Crocodiles and other fauna excavated from nearby Ellesmere Island Turtles, Crocodiles and other fauna excavated from nearby Ellesmere Island

7 The Eocene Climatic Optimum Birches, laurels, tulip trees, metasequoia, and other deciduous tree species lived happily at 83 N, where six months of darkness prevailed! Birches, laurels, tulip trees, metasequoia, and other deciduous tree species lived happily at 83 N, where six months of darkness prevailed!

8 Ocean Circulation Some researchers believe that ocean circulation holds key to long-term changes Some researchers believe that ocean circulation holds key to long-term changes Continental drift allowed circumpolar flow around Antarctica in the Miocene Continental drift allowed circumpolar flow around Antarctica in the Miocene Renewed glaciers in Antarctica Renewed glaciers in Antarctica

9 Sea Level Changes Sea level has also been much higher throughout recent Earth history Sea level has also been much higher throughout recent Earth history Our most recent ice ages

10 Rapid Changes Can Also Happen! Paleocene-Eocene Thermal Maximum (PETM) Paleocene-Eocene Thermal Maximum (PETM)

11 Paleocene-Eocene Thermal Maximum Ocean responded within 10,000 years. Ocean responded within 10,000 years. Caused by sudden release of methane(?) from the continental shelf (??) Caused by sudden release of methane(?) from the continental shelf (??) Back to normal within 100,000 years Back to normal within 100,000 years

12 Earth Today: The Ice Ages We live in an icehouse period that has been around for the last ~1 million years. We live in an icehouse period that has been around for the last ~1 million years. Typified by short warm interglacials and then long declines into glacial episodes. Typified by short warm interglacials and then long declines into glacial episodes.

13 What causes these cycles? Changes in the Earths orbital parameters (Milankovitch cycles). Changes in the Earths orbital parameters (Milankovitch cycles). –Distance to the sun –Precession of the Earths axis –Changing of angle of inclination These dont work all that well, but no one has a better idea! These dont work all that well, but no one has a better idea!


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