Global Warming? How many times in geological history has the polar ice caps been free of ice?

Question

I haven't been able to find any credible sources on the history of the polar ice caps. But, I have heard that the polar ice caps have been free of ice many times in the history of the plant. Is this true? If this is true is this big global warming issue a little over blown because this would be just a natural cycle of the earth. If this has happend before, melting of the polar caps, what has happend in the past?

Answer 1

Many, many times.

Here is one reference that is certainly credible:
http://www.homepage.montana.edu/~geol445/hyperglac/time1/time.htm

You can see that even in recent times (past 250,000 years) there have been nonglacial periods. During the Eocene (33-56 million years ago) there were alligators near the North Pole, and palm trees in southern Alaska.
http://www.scotese.com/earlyeoc1.htm
The Paleocene saw mangrove swamps near 65 degrees south latitude and palms in Greenland and Patagonia.
http://www.scotese.com/paleocen.htm
During the Late Cretaceous, no ice existed at the poles.
http://www.scotese.com/lcretcli.htm
During most of the Jurassic, there were not likely to have been any long-lasting ice caps, and during the Triassic no ice existed at either pole.
http://www.scotese.com/ltriascl.htm
http://www.scotese.com/etriascl.htm

Here is a graph showing the Ice House and Hot House periods of earth's climate over the last 2 billion years:
http://www.scotese.com/climate.htm

Answer 2

had to go all the way to the bottom to find someone saying what needed to be said. The history of the earth is like a book with many many missing pages. It is hard to say that something didn't happen in the story for those parts where the pages are missing.

I can only think of three periods apart from the present ice age where there is evidence for large scale glaciation: during the early proterozoic (mostly as marine dropstone sediments rather than tills), during the late proterozoic, and when Gondwana was down around the south pole. During the rest of the time, it appears to be an open question.

The absence of proof isn't proof of absence, as I recall hearing at some time in my life, but it sure is enough to make you think it could have been ice free during a lot of that time. There is definitely evidence that the global climate was warmer than now at many points in the past billion years or so.

But I am all for the stopping waste and pollution, even if I do not think global warming is as horrible as people make it out to be. We will still be in a lot of trouble for other reasons if we don't start to work with the (earth) system instead of without regard for it. So you should feel guilty for driving that SUV lol.

Answer 3

The same quantity of water, when it is in a solid state occupies a larger volume than when it is in a liquid state, therefore it is less dense, and that is why it floats. Get a bowl, fill it half full with water, and some ice cubes, mark the water level, then wait for the ice to melt and remark the water level, you will see that the level has not gone up, but maybe, if you are very accurate, you will see that it has gone down. The Arctic ice cap is mostly sea ice, so even if it all melted it would not cause flooding of our coastal areas. As for Antarctica, the peninsular (3% of the land area) is warming, but both satellite and ground measurements show that the main bulk of the continent (97%) is getting colder. In 1988, one of the UN's '2500 scientists' reported to congress that by 2000 that sea level would have risen by several feet, a reality check in 2000 showed that it had not risen even 1 inch. Exaggerated claims are being made for political reasons, and should be viewed with a healthy dose of scepticism

Answer 4

the planet goes through the same cycle over and over but the thing about global warming is that we are just speeding it up tremendously. If we reduce everything emitting greenhouse gases, we could slow it down and have the earth stable for a few years, allowing us to live here longer.
as for the number of times in geological history the polar ice caps been free of ice i dont think anyone really knows.

Answer 5

You need to phrase this question the other way: How many times in the Earth's past have the polar regions had ice caps? Two major periods of continental glaciation are known: during the Edicarian (before the Cambrian) and during the Permian. Several minor epochs of glaciation are known, the latest being the Pleistocene/Holocene. Most of the Earth's history shows no glaciation at the poles.

Answer 6

DO NOT GET YOUR SCIENCE FROM POLITICIANS AND SPECIAL INTEREST GROUPS.

Global warming is real. So is global cooling. Its a natural cycle. We are currently exiting an ice age. Will the warming continue? Maybe. Are we speeding it up? Maybe, but there's not a good way to quantify that.

Sharen - The Earth will end a precession cycle near 2012. It will not change its rotation. Jeez, pay attention.

Answer 7

go to history .com or discovery ,com and it will show you the actual time table for this what happens is usually the earth,s polar caps melt the earth gets flooded and very very hot where humans really wont have a chance for life than the earth will freeze and things will change this usually happens every thousand s of years , when the earth aligns with the milky way on 2012 DEC 21 the earth will change her rotation to the opposite direction this also happens every billions of years so the Maya have told of as well as the planet her self . where there were once oceans there are none now but the earth is ready to change all that this is why our weather will get worse as the years get closer to her cleansing stage.

Answer 8

I have seen lots of anti-global warming videos (either by or supporting leading authorities in this area (even people high up in greenpeace dont support human-caused global warming)) and if you go back millions of years we are actually a lot colder than the earth has been, the temperature tends to go Warm, then Ice Age, than warm then ice age (note these changes happen over many years). Al Gore is just trying to get votes by pretending to care.

Answer 9

I agree that it is too narrow and assumptive to say Co2 is causing all of the climate change. They never seem to look at the whole picture and include all the other gases, the Sun, natural cycles, the oceans and how we're killing them, etc, etc. Most of the scientists look relatively clown-like to me unless they really sound like they know their stuff.

edit: I think mankind poisoning his planetarium is worse than warming it.

Answer 10

You need to do more research. Yes, it's sometimes normal, but this time it's correlating with *enormous* amounts of CO2 that 6 billion humans have created, more than we've seen naturally in 600,000 yrs. At any rate, it's a very complex topic and you won't get a good answer here. The vast majority of atmospheric scientists believe it anthropogenic, but there are a few that disagree.