1. Global Warming
Or Climate Hysteria?

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

3. Greenhouse World Cretaceous Period was one of significant warmth.
Tropical temperatures not much different.
Much warmer at poles – no ice!
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 Eocene
Climatic Optimum

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

6. The Eocene Climatic Optimum
Tropical fossils found at high latitude.
Fossil forest sites on Axel Heiberg Island, NWT, Canada
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!

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

9. Sea Level Changes
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)

11. Paleocene-Eocene Thermal Maximum
Ocean responded within 10,000 years.
Caused by sudden release of methane(?) from the continental shelf (??)
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.
Typified by short warm interglacials and then long declines into glacial episodes.

13. What causes these cycles?
Changes in the Earth’s orbital parameters (Milankovitch cycles).
Distance to the sun
Precession of the Earth’s axis
Changing of angle of inclination
These don’t work all that well, but no one has a better idea!