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Are we heading into a new Ice Age?

What the science says...

Select a level... Basic Intermediate

Worry about global warming impacts in the next 100 years, not an ice age in over 10,000 years.

Climate Myth...

We're heading into an ice age

"One day you'll wake up - or you won't wake up, rather - buried beneath nine stories of snow. It's all part of a dependable, predictable cycle, a natural cycle that returns like clockwork every 11,500 years.  And since the last ice age ended almost exactly 11,500 years ago…" (Ice Age Now)

According to ice cores from Antarctica, the past 400,000 years have been dominated by glacials, also known as ice ages, that last about 100,000. These glacials have been punctuated by interglacials, short warm periods which typically last 11,500 years. Figure 1 below shows how temperatures in Antarctica changed over this period. Because our current interglacial (the Holocene) has already lasted approximately 12,000 years, it has led some to claim that a new ice age is imminent. Is this a valid claim?

Figure 1: Temperature change at Vostok, Antarctica (Petit 2000). The timing of warmer interglacials is highlighted in green; our current interglacial, the Holocene, is the one on the far right of the graph.

To answer this question, it is necessary to understand what has caused the shifts between ice ages and interglacials during this period. The cycle appears to be a response to changes in the Earth’s orbit and tilt, which affect the amount of summer sunlight reaching the northern hemisphere. When this amount declines, the rate of summer melt declines and the ice sheets begin to grow. In turn, this increases the amount of sunlight reflected back into space, increasing (or amplifying) the cooling trend. Eventually a new ice age emerges and lasts for about 100,000 years.

So what are today’s conditions like? Changes in both the orbit and tilt of the Earth do indeed indicate that the Earth should be cooling. However, two reasons explain why an ice age is unlikely:

  1. These two factors, orbit and tilt, are weak and are not acting within the same timescale – they are out of phase by about 10,000 years. This means that their combined effect would probably be too weak to trigger an ice age. You have to go back 430,000 years to find an interglacial with similar conditions, and this interglacial lasted about 30,000 years.
  2. The warming effect from CO2 and other greenhouse gases is greater than the cooling effect expected from natural factors. Without human interference, the Earth’s orbit and tilt, a slight decline in solar output since the 1950s and volcanic activity would have led to global cooling. Yet global temperatures are definitely on the rise.

It can therefore be concluded that with CO2 concentrations set to continue to rise, a return to ice age conditions seems very unlikely. Instead, temperatures are increasing and this increase may come at a considerable cost with few or no benefits.

Basic rebuttal written by Anne-Marie Blackburn

Update August 2015:

Here is a related lecture-video from Denial101x - Making Sense of Climate Science Denial


Last updated on 7 August 2015 by MichaelK. View Archives

Printable Version  |  Offline PDF Version  |  Link to this page

Argument Feedback

Please use this form to let us know about suggested updates to this rebuttal.

Further reading

Tamino discusses predictions of future solar activity in Solar Cycle 24.


Many thanks to Sami Solanki for his invaluable advice and feedback as well as John Cross for his very helpful comments.

Further viewing

potholer54 published a video tackling this myth on June 27, 2020


Dave Borlace explains why we are not headed towards an ice age in this "Just have a think" video published in December 2019:



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Comments 201 to 225 out of 410:

  1. Henry Justice @198 - "Also, I checked the worlds annual mean temperature charts. Not much of a visual upward slant in temperatures everywhere I looked world wide for the last 50 years. The urban site temps were not used as they are unreliable. So upward and downward wiggles appear all but natural variations. Look for yourself and you be the judge!" Okay. Comparing all the temperature records Henry, the three surface temperature records and both satellite records all show warming. Where have you been looking?.
  2. Henry Justice - " In Greenland, eight WW2 bombers from the "lost squadron" were found in 1986 under 267 feet of ice. How's that for melting glaciers? I didn't take the rest of the article seriously." Yeah, heard that one before. And the one about the research station being buried under many feet of snow, and having to be dug out. Please note that the center of the Greenland Ice sheet is at high elevation, is very cold and is still accumulating ice. The coastal regions where the glaciers meet the sea, are not, and are rapidly melting. The loss of ice at the coast far exceeds the gain from snowfall at high elevation, this is why the Greenland ice sheet is losing many billion of tonnes of ice every year.
  3. Henry @198, I'm afraid you have been hoodwinked by some folks who, on the surface, seem to make a compelling case. Research has shown that even if we do enter another Maunder-like minimum, or even a grand minimum, the radiative forcing from elevated GHGs will easily overpower the reduced incoming solar radiation. See this thread for details.
  4. #195 . WRONG !!! the satelites together with earth should form one system that it should be moved together in the apply of gravitational forces due to planetary realligment , yet the sun stays steady ....
    Response: [Daniel Bailey] Again, please provide linked references for those claims (published, peer-reviewed sources have the most credibility). Extraordinary claims must of necessity be accompanied by an extraordinary evidenciary chain. Unsupported comments such as yours will be simply deleted in the future. Thanks!
  5. @kfdv #190 Are you aware this is all written, aren't you? What do you suppose students will think about when they analyze your answer to #188 ?
  6. Have any of those individuals pointing to the “Petit 2000” graph actually bothered to look at it and study what it means? According to the graph if you move backward through time to "now" you see a rapid increase in temperature - consistent with other ice ages - but the highest temperature reached, during the present temperature increase period, never reaches the same high it reached in previous ice ages. The high in previous periods is over 3 deg above the baseline whereas it is less than 2 deg above the baseline for the present. How can anybody interpret this as a temperature rise that’s out of control? If we’re in the middle of a glacial warming period it stands to reason that each year will be warmer than the next until the warming trend ends. BTW: The most efficient way to transfer thermal energy is by convection. If you remember your physics there are three ways to transfer thermal energy – radiation, conduction and convection. Why does the GW model only consider the meager role of radiation heat transfer when convection heat transfer is far more efficient?
  7. Dorianmc, Firstly, who said we were undergoing runaway temperature increases? So far warming has been very tightly controlled, doing pretty much what climatologists said it would do in reaction to increasing CO2 levels. Secondly, we're in the middle of an interglacial period that should be cooling according to natural forcings, but it isn't. Temperature is spiking rapidly on a geological timescale. Thirdly, exactly how do you know that radiative transfer is "meager"? And what gives you the bizarre idea that convection isn't taken into account? Which model states that only radiative effects are taken into consideration? Your previous post is a rambling mess of assertion.
  8. Dorianmc forgets (or is unaware) of the multiple layers of the atmosphere and that at the level of the TOA, convection is largely non-existent and radiative transfer rules. And that at no point in the last several interglacials did CO2 concentrations ever approach what they are today, heightening the importance of back radiation. Also remember that the zero baseline of Petit 2000 was 1950. Let's take a look at that whole timeframe, extending it to today's CO2 levels: A re-watching of Alley's talk would be instructive here. The Yooper
  9. #206: "it stands to reason that each year will be warmer than the next until the warming trend ends." That would be nice, if we lived in some kind of cartoon-world, where the requisite laws of cartoon physics apply. However, you may be aware we had a 'Little Ice Age' and have fully recovered from that. So your idea that there's any possibility of monotonically increasing temperatures is not even lukewarm.
  10. Perhaps I'm missing something,but several things jump out of this graph: 1) The data only goes back about 430,000 years, yet the axis goes back 450,000 years. Why? To me it looks as though someone has removed the first part of the line. I'm not saying they did, but such things do happen from time to time. In this instance it's a fairly critical question because the interglacial that occurs at the left of this graph is allegedly the closest fit to the one we have now in terms of the alignment of the planet. 2) It is apparent that the later data is at a high level of granularity than the more recent data, you can see this by the spikiness (thickness) of the line. This is not surprising because the closer we get to the present the more data we have. However it does somewhat skew one's perception of the graph because when we look at 430,000 years ago compared with now, we are not - in graph terms - comparing apples with apples, due to the granularity difference. I strongly suspect that if the graph was drawn with uniform granularity then the temp change 430,000 years ago would appear more similar to the present temp change. 3) The temp peak in this current interglacial is presently a very thin one at 2C. Other than that the temp appears to be hovering somewhere between 0-1C, this is actually lower than in pervious interglacials, all of which peak between 2-4C. 4) There are only really 5 samples of interglacials represented here and that really isn't much of a data set. Now I fully appreciate that this can;t be help given the time periods in question, but it doesn't change the fact that there are only 5 samples for comparison. Humans are as yet hopeless at predicting localised weather let alone the climate. This doesn't mean people shouldn't try but perhaps they should hold back predicting catastrophes until we have a better understanding. For all we know the super volcano in Yellowstone National Park could go off in a few decades and that would really throw a spanner into the works. The Earth is a living planet, and nature takes no prisoners. Personally I am glad of all this hoo-har over climate change because if nothing else it is teaching people not to mess around with nature. Unfortunately that doesn't mean that won't mess around with us and everything else on this planet. If nature chooses to make some changes then - take note kids - human beings are powerless to do anything about that. Get used to it. In LVX
  11. Here is the full graph. Shows a more similar curve between 430,000 years ago and now:
    Response: [Daniel Bailey] Not so similar. Remember that ice core temperature reconstructions use 1950 as year zero. Here's what that would look like if CO2 were extended to today's levels (I do seem to be having to show this illustration a lot lately!):
  12. #210: "if the graph was drawn with uniform granularity..." If the graph was drawn uniformly, it would be a misrepresentation of the data. The time resolution of an ice core (and many conventional cores) decreases as you move downhole (older). Petit et al 1999 is the classic description of how these data are obtained. The mean resolution of the CO2 (CH4) profile is about 1,500 (950) years. It goes up to about 6,000 years for CO2 in the fractured zones and in the bottom part of the record "... only really 5 samples of interglacials represented here and that really isn't much of a data set." Why is this a concern? This isn't a pattern matching exercise.
  13. Re: Blueflash (210) 1. Read the study (petit et al 1999) 2. IBID. Then read this. 3. You expect all glacial epochs to be Xerox copies? 4. 450,000 years of data, multiple cores. Say what you want, but it doesn't change the fact that that's an awful lot of years and even more snowflakes. Humans do a pretty good job at understanding past and present ongoing climate change and predicting future climate changes. Strawmen distractions about off-topic supervolcano's aside (we are overdue for a Yellowstone blow, tho), human beings are pretty capable of screwing the planet up. Get used to it. The Yooper
  14. Daniel, 1) The graph I was referring to was a temperature graph. The one you have responded with is a CO2 graph. 2) "For 650,000 years, atmospheric CO2 has never been above this line... until now" uses misleading grammar. The word "never" has strong implications. And 650,000 years is not a long time in the grand scheme of earth. The correct phrasing would be "CO2 has not been above this line in the past 650,000 years."
    Response: [Daniel Bailey] Sigh. In reverse order (feeling contrarian myself today), 650K years is an immense time in the history of our species; the Earth will abide long after we are gone (unless we get too many handwaving comments). CO2's peak in the Vostok core was 298.3 PPM. The line was to represent 300 PPM. Grammar concerns notwithstanding, the point is unequivocal. And for those who refuse to acknowledge any relationship between CO2 and temps:
  15. Please excuse my ignorance, but are you saying that the increased CO2 levels responsible for global warming have kept us from entering into an Ice Age? Shouldn't we be glad of that? Or is it the case that this global cooling period/Ice Age wouldn't have affected us in our lifetime, or the lifetimes of future generations and as such wouldn't have been of concern anyway? I'm just a little confused now.
  16. The current interglacial would have ended in about 10 thousand years based on the natural cycles. Hence, not really a concern for humanity.
  17. Re: Mr_Pants (215) Welcome to Skeptical Science!
    "Please excuse my ignorance, but are you saying that the increased CO2 levels responsible for global warming have kept us from entering into an Ice Age?"
    I'm not saying it is or isn't in the definitive sense, but the emerging evidence would seem to indicate that.
    "Shouldn't we be glad of that?"
    Dunno. Personally, I'm glad to have a job and a family that loves me.
    "Or is it the case that this global cooling period/Ice Age wouldn't have affected us in our lifetime, or the lifetimes of future generations and as such wouldn't have been of concern anyway?"
    Absent the warming effects of the CO2 bolus we've injected into the air, then the understanding is that the Earth would've continued its gradual cooling trend from the Holocene Optimum for at least the next several thousand years before any onset of an ice age would've become worrysome. But that's neither here nor there. Of bigger and more immediate concern is what damage the warming still in the pipeline will do to our climate and crop production:
    "I'm just a little confused now."
    Been there, done that. The Search function in the upper left corner of every page is your friend here. If you have questions, type in a few keywords & search away. Odds are there's a thread or three here covering that topic. For some good background on Skeptical Science and climate science in general, go here and here. Enjoy! The Yooper
  18. Even if there was eminent danger of mile-high sheets of ice sitting on Minnesota, such as in 'Fallen Angels' by Larry Niven, we have already drastically overshot the mark.
  19. #218: Biblio, Maybe we could build a Ringworld. It would be cooler (from a scifi point of view).
  20. @ 219 I hear General Products was founded by Koch Industries... The "Louis Wu" Yooper
  21. #220: Ha! Even the Puppeteers were done in by what could only be called PGW The Puppeteers had to make some drastic alterations to their home system, during their history, as waste heat due to overindustrialisation was rapidly making their planet uninhabitable. They moved their planet further from their sun, to lessen the effects of global warming ...
  22. @ 221 You mean...they had their own waste heat thread? One is enough to do in any civilization, apparently.
  23. There seems to have been several comments in this thread regarding the shifting of the axis of the planet. I don't know whether those who propose such things simply do not understand how the planet moves in space and interacts with it's environment, or are simply misunderstanding some real events and relationships. For the record. The axial tilt of the planet moves. Over a period of about 41,000 years it gradually "wobbles" from 21.2° to 24.1°. On it's own the effect on climate will not be that great as it accounts for something in the region of a variance of about 0.021 W/m² of solar radiance, hardly enough to have a drastic input on it's own. This wobble has a wobble imposed upon, that also has a could say that the wobble has a wobbling wobble!! However, joking aside, these are minor and do not have any real effect. There is no evidence that I am aware of showing the axis of the planet has ever exceeded the extremes of the wobble I mention in the last 4Gy, thus I think it unlikely too now. Where I feel many laymen get confused is between the axial pole and the magnetic pole, which are wholly separate. The Magnetic pole wanders about like a drunk, all over the place and up to 40km per year, currently it holds a Canadian Passport! Further, it is a proven fact that the magnetic pole does "flip" and also disappears for short periods, perhaps up to 10,000 years, and this process is not understood really, although theories abound as to the cause. Whether there is an interaction between these magnetic reversals and the climate I do not know, I don't think any research has been done in this respect, but I stand to be corrected on this. Any sceptic who claims that the axis of the planet changes drastically and this causes Ice Ages, Warm periods, sea level changes or even the death of species is talking out of their hat and they do not do the debate any favours at all as they simply make those who question the climate research conclusions seem like crack pots. Now perhaps we can avoid discussion of the planets axis moving and stay on track?
    Response: I'm unsure whether you are arguing against the existence of Milankovitch cycles, but if you are, you are wrong. You can see Richard Alley explain it in 30 seconds. Doing an internet search for "Milankovitch cycles" will get you a bunch of diagrams, animations, and explanations. That will help you understand when you reread the original post at the top of this page.
  24. @ Response...surely you have a name :) I am unsure why you feel I was arguing about Milankovic cycles, and I wonder if you read my post correctly? I am not arguing against Milankovic cycles in the slightest, on the contrary, I am a firm believer that these cycles can and have played a part in the varying climate here on Earth, but I think this is only when they coincide with other effects that are "home grown" on Earth and simply add to it. My comments are self explanatory, the axis of the planet does not shift beyond the natural variance I noted and firmly believe that many get this mixed up with magnetic pole displacement, which is a proven scientific event in Earth history. Many seem to misunderstand the motion of the planet in space, and seem to think these changes have a greater impact on Earth than they do. Combined they may well have a big effect, but as far as I am aware, no-one has created a model of the solar system accurate enough to models our planet's motion in space over the last 4 billion years to see whether, at any time, the disparate cycles have ever coincided enough to have anything more than an arbitrary effect. That is why the last paragraph of my post was worded the way it was. I am not convinced by AGW, but if one is to argue against something, then one must do it with credible arguments that at least are worth research time, and polar shift of the planet is not one of them
    Response: You just now did argue against the dominant role of Milankovich cycles in triggering ice ages. Make up your mind.
  25. #224: "models our planet's motion in space over the last 4 billion years ... " A complete and utter red herring strawman. There is more than enough understanding of the current orbital dynamic to fully describe the orbit's control over solar insolation. There is more than enough measurement of insolation to fully describe its input to earth climate. "... to see whether, at any time, the disparate cycles have ever coincided enough to have anything more than an arbitrary effect." What does that even mean? What is an 'arbitrary effect'? "I am not convinced by AGW" Let's try to establish credibility rather than make declarations. Have you read each of the SkS threads relevant to whatever aspects of AGW you disagree with? Have you weighed the arguments of actual scientific research against 'I am not convinced'? What specifically do you disagree with? Can you mount credible cases against the points made in the relevant SkS threads to qualify as scientific arguments? Those who arrive at SkS already in a confirmed state of denial usually wind up with little more to do than pose red herrings and make blanket 'no its not' statements. Nobody said understanding AGW was easy; being a competent skeptic certainly isn't easy either.

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