What causes an Ice Age, we have had three so far, and will we ever have another?

Answer 1

The main cause of any ice age is a continent over the pole.

Since Antarctica is over a pole, that land gets really cold and can't warm up very fast. Usually, there is water over the poles, and the cold water can easily circulate and regulate the planet better. Land doesn't circulate, so the cold just gets colder. So, Antarctica's occupation of the pole, starting at ~5 Ma (million years ago) has lead to our current ice age.

In the Permian (250 Ma), it was the tip of Gondwanaland (southern Africa/South America). The older glaciations are more speculative (see link).

As long as a land mass occupies a pole, we'll be in an ice age and experience cycles of glacial maxima and minima. We will stay in the pattern for about another few million years (though our greenhouse gas emissions may cancel that out). The fluctuations (maxima/minima) you get (on a ~10 000 to 100 000 year scale) within an ice age, which most mistakenly assume entails the whole ice age, is caused by climate patterns and astronomical cycles.

Once we finish this ice age (i.e. Antarctica leaves the pole), we may get one again when Australia or something else goes over the south pole or N America/Greenland/Siberia goes over the north pole.

Will we go back into a glacial maximum soon? It is possible, but global warming is raising temperatures faster than anything is cooling.

Answer 2

There have been many more periods of glaciation than three. A good example of major glaciation that was at the Proterozoic-Phanerozoic boundary when the Earth exited major glaciation resulting in the Cambrian Explosion (of life). Some scientists believe we are still in an Ice Age at present since ice on the planet Earth is rare, even at the polar regions. Causes of glaciation are not well understood, although glaciation during the Permian is thought to have occurred due to the formation of the supercontinent Pangaea.

Answer 3

One hypothesis on the causes of continental glaciation ties periodic Northern Hemisphere ice ages, or glaciations, to periodic instability and surging of the Antarctic Ice Sheet. Instability is believed to occur when glacier buildup becomes so great as to cause pressure sufficient to melt the base of the ice sheet. Then, riding on water, the East Antarctic ice dome rapidly collapses, and, according to the hypothesis, the outflowing ice forms extensive ice shelves reaching perhaps to the Antarctic Convergence. The resulting increased reflectivity over such a large area would then cool the entire Earth. Once collapsed, the ice-dome base would no longer be at the pressure melting point, and the ice shelves, no longer fed, would soon disappear by calving and melting. Consequent decreased reflectivity over the Antarctic Ocean would then result in global warming and thus an interglacial period. The process could repeat itself many times.

Answer 4

We've had a lot more than three ice ages. From what I understand, they recur roughly every ten thousand years.

Will we have another? Certainly. However, that will most likely be a problem for our descendants some centuries or millenia from now, it's not something we really need to worry about.

Answer 5

If we didn't mess with the environment as much as we do, then yes, we could have dozens more ice ages. It's how the Earth works, it goes into periods of extreme heat and cold. Right now, we are about in the middle of a heat period. It takes thousands of years though, so worry not, it will not happen by tomorrow.

Answer 6

There was no Ice Age since the world started at 4000 B.C.... That's what I would say if I denied science.