at least twice in the history of Earth, the planet has been completely covered in Ice from the poles to the equator.

Who validated this post?

 

It is quite clearly not a debate challenge.

I believe you want to debate the snowball earth theory, correct?

at least twice in the history of Earth, the planet has been completely covered in Ice from the poles to the equator.

 

I saw a good documentary on this a couple of years ago. Evidence seeming to back it up is rock formations at equatorial locations at the right times that demonstrate full equatorial Glaciation was present at the time.

The Theory was challenged for some time because no-one could figure out how the earth could escape the snowball scenario. High reflectivity globally could have made it permanent.

The saving grace it seems was CO2 buildup from Vulcanism. Volc's had no problem busting through the ice sheet and without plants or free water to absorb the CO2 it built up a powerfull greenhouse effect over 15-20 million years, eventually causing a runaway thaw.