Was Earth Headed for the Mother of All Ice Ages Before Global Warming?

By Eliza Strickland | November 13, 2008 10:09 am

ice age projectionBefore we humans came along with our Industrial Revolution and our greenhouse gases, the earth was hurtling towards an intense ice age that could have covered much of the northern hemisphere with deep ice sheets as soon as 10,000 years from now, according to a tentative new study. But that’s no reason to thank our lucky stars for global warming, says study coauthor Thomas Crowley: “We’re creating a situation at least as dangerous, only going in the opposite direction” [Wired News].

Climate data shows that complex life evolved on a much warmer “hothouse earth,” and that the planet has been gradually cooling for the last 50 million years. Then, 2.5 million years ago, the climate entered a curious new phase: it started oscillating wildly, see-sawing between interglacial periods with conditions similar to today’s and ice ages during which the amount of permanent ice in the northern hemisphere expanded hugely. At the peaks of these transient ice ages, much of northern Europe, northern Asia and North America were covered in ice sheets [more than 2 miles] thick, and sea levels were [almost 400 feet] lower than today [New Scientist]. The new study argues that this period of oscillations was a transition to a stable, long-term ice age that would have made those previous ice ages look like mere cold snaps.

But Crowley says his findings deal with how the earth’s climate would have shifted naturally, without the influence of humankind, and says that man-made increases in greenhouse gases in the atmosphere will likely throw all his projections out the window. Present carbon dioxide levels are probably sufficient to prevent his predicted ice sheets from ever rolling over Europe and Asia, Crowley says.

The study, published in Nature [subscription required], relies heavily on computer projections, and still needs corroboration: “It’s not proven but it’s more than just an interesting idea,” says Crowley [New Scientist]. But other paleoclimatologists expressed skepticism about the results. Prehistoric-climate expert Lorraine Lisiecki said, “This is the only study of which I am aware that suggests the next ice age could be much more extreme than those of the previous one million years.” … But she agreed that we might never find out what would have happened naturally, due to human-caused global warming [National Geographic News].

Related Content:
80beats: Did a “Little Ice Age” Create Special Wood for Great Violins?
80beats: A Monstrous Methane Belch Once Warmed the Earth

Image: T. Crowley & W. Hyde

  • levin

    Well whoever did their research on this, and actually posted this article needs to brush up on their facts…

    The warming is what is actually speeding up the ice age. There are many ways that rises in temperatures cause ice ages… but here’s on of the main ones:

    Ice Caps melt leading to less salinity in oceans. Salt lowers freezing point, less salt raises that freezing point. That should be enough for you bozos to be getting on with.

    I expected more from this blog…

  • Bill

    When I first read the caption I thought this was one of those many scientific articles (and I use “scientific” liberally here, since there was no science in them), which began in 1972 in SCIENCE magazine, which stated that man made polutants were blocking out the sun, while aerosols in the upper atmostphere were reflecting sun light back into space creating a cooling period that was going to produce a MAN MADE ICE AGE. After the Little Ice Age, in 1860, earth entered into a revolving 40 year temperature cycle. From 1860- 1900 temps fell each year. In 1901, temps rose each year till 1940. In 1941, temps fell each year until 1980, in 1981 temps began to rise again and continue to, untill 2020? We’ll see in 12 years. In 1982 however, as this magazine reported, the sun entered what solar researchers are calling a 1,000 year peek in solar activity. Meaning the sun started giving off more light, heat and solar wind. The sun’s magnetospher increased as well. Al Gore claimed that this increase in the suns output had nothing to do with the global warming he says happened at the same time, but is it really posible that he is right? That a 1000 peek in solar output would not warm the earth?

    The earth will, in 15,000 years, start to move away from the sun starting into our next ice age, and it may well be greater, but not because of us, but rather the dynamics of the Second Law of Themo-dynamics “Entropy increases.” As the earth has orbited the sun, it has gradually over billions of years, developed a wobble. the stable starting orbit of the earth around the sun has been decaying, getting more chaotic, in keeping with thermo-dynamics. At first the wobble was miniscule and did not effect the earth’s temberature, however, that wobble has been getting bigger, a few million years ago, it became so significant that it started to cool the earth. This wobble will continue to get larger entrip continues to increase adn our earth’s orbit decays into chaos. So future ice ages will becme more severe as the billions of years pass. Eventually, the wobble will take the earth so far out from the sun, that we will just drift off leaving our sun behind.

  • Erik

    I am interested in hearing what you think the answer to your question is. Would a 1000 peek in solar output would not warm the earth? What you stated is that researches called it a “1000 year peak in solar activity”. Is there not a difference between activity and output? Meaning that activity does not always equal heat. Are you a Solar Physicist? Activity to me, means there is more to see in H-alpha light, along with sun spots in white light. I thought it also represent cooling during an approximately 14 year cycle from maximum to minimum. I would like to hear your reply wether are not you are a physicist. I did really like everything else you wrote. I have heard global warming skeptics say the same people that warn of global warming warned us about another little ice age. The science of doubt to stop governments from greenhouse gas reductions?

  • Lewin

    “The warming is what is actually speeding up the ice age. … That should be enough for you bozos to be getting on with.”

    Good point. If we want to avoid an ice age, we should hope that temperatures fall as much as possible.

  • Laurentiu

    ok, so the assumption is made that the IPCC headed by a railway engineer and Dr Hansen are correct; look at their latest snafu using the wrong data for October; government, duh; they claim of being 100 percent sure yet have no clue if the data they use for input is correct or not.
    Then I have a problem with these “computer models”. Tell me they are not based on some assumptions. And tell me those assumptions are absolutely 100% correct.
    You can torture the data to confess to crimes it has not committed.

  • http://None Roy Wilson

    I enjoyed your comments, and the data certainly seems to back up your contentions. It should be interesting to see if the 40 year cycle does end in 2020 – time will tell.

    As to the “warming” trend speeding up a new ice age, I seem to remember an article from about the 1960’s, possibly in the old LOOK magazine, that hypothesized that a new ice gae would begin when the North Polar Cap melted and cold arctic winds began picking up huge increases in moisture from the unprotected Polar Sea and distributed this moisture as snow and ice southward. I’m aware of the hypothesis that the “conveyor current” could become disrupted and lead to cooling, as well as wide climate swings in the Northern Hemisphere, but I wonder if these two things work together to bring about climate change?

    I realize this comment is more than a year after your comment, and will probably be lost “somewhere in time”, but I was just curious.


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