Johnny Ball's environmental science claims

[Tony Williams]

Do you have a link for that - I'd love to read it!

http://www.physorg.com/news174247209.html

I think 'know' is a bit strong for the snowball Earth hypothesis..

Point taken, although there seems to be quite strong evidence for it: http://www.snowballearth.org/

[Harryprice]

http://www.physorg.com/news174247209.html

"... we know that at different times the poles have been tropical ,,,"

/

OK, you mean there were high temperatures at the poles. The tropics are a place, not a temperature. I thought you meant something else, like Earth tilt changing.

[Croydon Bob]

The tropics are a place, not a temperature. I thought you meant something else, like Earth tilt changing.

Has that definitely never happened?

[Harryprice]

Has that definitely never happened?

Dunno. Found this though.

[chaggle]

http://en.wikipedia.org/wiki/Catacly...ift_hypothesis

Among the scientific community, the evidence shows that no rapid shifts in the pole have occurred during the last 200 million years.[2] True polar wander is known to occur, but only at rates of 1° per million years or less.[3] The last rapid shift in the poles may have occurred 800 million years ago,[4] when the supercontinent Rodinia still existed

But

http://www.habtheory.com/1/100.php

Expanded Discussion of The HAB Theory