Earths climate throughout geological history

Reader Peter Lang kindly sent me these interesting links.
Here are links to three sites on past climate and one with plate tectonics animation:
1 Paleomap by Scotese:
Schematic chart of average global surface temperatures for the past 600 million years (since multicell animal life began)
Points to note:
The planet is in a ‘cold-house’ phase
There have been only three ‘cold-house’ phases since animal life began. We are in the third one now.
The planet’s normal temperature is about 8 C warmer than present
Life thrives when the planet is warmer, struggles when colder
Life loves warming, hates cooling
Warm is better for life. More food.
We acknowledge there are costs of change, but overall, warmer is better for life.


2. James Hansen (the ‘father of climate change’ alarmism) (see Figure 1)
Figure 1 shows that the Earth has been cooling for the past 50 million years. Once ice began to accumulate at the poles, first the south pole and later at the north pole, the climate became much more volatile – we started cycling in and out of ice ages.
Message to take from this: when the planet is warmer the climate is more stable than when colder.

3. IPCC, AR4, WG1, Figure 6.1 showing global temperature for the past 400 million years
Points to note:
There has been no ice at the poles for 75% of the past 500 million years (since multi-cell animal life began)
The planet has been cooling of the past 50 million years
Ice started accumulating at the South Pole 35 million years ago and at the North Pole 5 million years ago
The climate is much more stable when there is no ice at the poles

4. Plate tectonic animation for the past 150 million years

2 comments to Earths climate throughout geological history

  • David Brewer

    This is timely, as Nick Minchin got done over on this on the recent ABC show I Can Change Your Mind About Climate Change.

    At 17 minutes on this video, a bloke at Mauna Loa tells him and warmist Anna Rose that CO2 is at its highest level for a million years. Anna says “that’s really scarey”, and Minchin manages to tell her not to get too excited, since it’s only gone from .03 to .04 per cent.

    But no one points out that for 90 per cent of the last million years the Earth has been in ice ages with temperatures 6 degrees colder than they are now and a third of the land on earth under many of metres of ice. Nor that previous interglacial periods were warmer than now, even though CO2 was lower. Nor that CO2 has been up to 15 times as high as it is now in geological history, and has averaged triple its current value. Nor that we are still several degrees below the average earth temperature during the period of life on earth.

  • Peter Lang

    David Brewer,

    Excellent points. Here are a few to add and to support your points:

    1. Go to the first link (Paleomap by Scotese) and click on the Earth History/Precambrian/ More Info/ item (in the left corner) / “Chart Summarizing Evolution of Atmosphere, Climate, and Life during the Precambrian”. or go straight to it with this link:
    www.scotese.com/precamb_chart.htm . Notice the CO2 concentration in the atmosphere through time. [Caution: this is a schematic diagram and much of the information predates the start of climate alarmism. That is both good and bad]

    2. I said that life thrives when the planet is warmer and struggles when colder. Evidence to support this statement is in many places, but even in IPCC. It is buried in text in IPCC AR4 WG1 Chapter 6. For example, Chapter 6 says words to the effect:
    – the area of deserts shrinks when the planet is warmer and increases when colder
    – the amount of carbon tied up in the biosphere is higher when the planet is warmer and less when colder (meaning life thrives when warmer)

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