ok, a SMALL bit of the climate change could have been plate shift. But even the MOST active plates have been moving less than an inch per year, and Antarctica is not one of them.
But giving it the benefit of the doubt, and using a worst-case 1" per year, only accounts for 1100 miles in 70M years. By comparison, the distance between the North pole and Nome Alaska today is 1700 miles, and no one calls that a "warm climate".
Even the Pangea theory says Antarctica was fairly close to the south pole 135M years ago (shown).
My own opinion, is that IF the earth's climate pendulum is currently swinging toward it's WARMER historical extremes, we're much better off than another ice age! (and the Kyoto global warming due-to-man theory is total B.S.)
Here's what U.W/Stout says about climate changes...
The earth has experienced numerous periods of global cooling and warming. The duration and intensity (degree of cooling and warming) of each period varies. As a period of cooling occurs, glaciers advance and the sea level falls. When warming occurs, the glaciers retreat and the sea level increases.
There exists some evidence that most of the earth's surface was once (maybe several times) covered with ice. This comes from studying the isotopic ratio of carbon 12 and carbon 13 found in ocean floor sediments. This ratio can be related to the average climatic temperature. These measurements suggests a global ice age (or a "snowball earth") happened around 570-700 million years ago and several episodes of glaciation have happened in more recent times (~1 million years ago).
The most recent period of extensive glaciation peaked about 18,000 years ago. Surprisingly, the average global temperature does not need to change significantly for there to be a period of large-scale glaciation. Only about 5oC change is necessary.
The Pleistocene Epoch (about 1 million years ago) of Geologic Time has been called the "Ice Age". About 20 cycles of warming and cooling occurred during this epoch. However, periods of glaciation have happened during other epochs (or periods) of geologic time.
- Why Does the Earth Experience Periods of Warming Or Cooling?
- Variations in the Earth's orbit and inclination to the Sun.
- Plate tectonics and the changing position of continents.
- Changes in the atmosphere. For example, if a sufficient number of volcanoes erupted in a short period of time, the amount of sun light penetrating the atmosphere may decrease from volcanic dust and ash in the upper atmosphere.
- Changes in sea water circulation.
Theories presented to explain periods of glaciation:
Theories 1 and 2 above, seem to hold the most promise and are often cited in explaining the periods of glaciation.
A detailed calculation (using the laws of physics) shows that the Earth undergoes slight variations in its motion with respect to the Sun. This causes differing amounts of sun light to fall on different locations at different times on the Earth. [Credit for the first such analysis is usually given to Milutin Milankovitch, a Yugoslavian scientist.]
- I. Eccentricity - One variation is that the Earth is sometimes closer to the Sun than at other times. This happens on cycles of about 100,000 years in duration.
II. Precession - The Earth behaves like a top that is spinning and placed at an angle onto a table. Instead of falling over, the top rotates around a vertical line. This happens in cycles about every 26,000 years.
III. Nutation - In addition to precessing about a vertical axis, the earth also wobbles (to a very small degree). A wobble which is described as a change in the angle to which the spin axis makes with respect to the orbital plane.
