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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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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)

At a glance

In something like a Day after Tomorrow scenario, the idea that a new ice-age was just around the corner was the subject of a book, a DVD and a website created in 2002. The author was a retired architect, by the way. Fortunately for us, both the movie and the quote above are figments of someone's fertile imagination. But let's have a quick look at ice-ages and what makes them tick, after which we hope you will agree that the notion that another ice-age is just around the corner is nonsensical.

Ice-ages, also known as glacials, are cold periods that occur in a cyclic fashion within an Icehouse climate state. Earth's climate has been mostly of the Hothouse type (no Polar ice-sheets). However, on occasion it has cooled down into Icehouse, as has been the case in the last few million years. There are regular variations in Earth's orbit around the Sun, taking place over tens of thousands of years. These affect the amount of Solar radiation reaching our planet. During the Icehouse state, such variations can lower and raise planetary temperature sufficiently to trigger swings between cold glacials – when ice-sheets expand towards the Equator – and mild interglacials – when the ice retreats back polewards.

To give an idea of the time-scales involved, Europe and North America have seen glacials and interglacials come and go repeatedly over the last 2.5 million years, this being known as the Quaternary Period of geological time. The last glacial period started 115,000 years ago and the Last Glacial Maximum (LGM), when the greatest ice extent was reached, was around 22,000 years ago. The current interglacial – also known as the Holocene, commenced 11,700 years ago.

A general pattern may be seen here with a long cooling down towards Glacial Maximum but a relatively quick warming into an interglacial. The speed of the warming-up part of the cycle is due to climate feedbacks. Removal of pale, reflective snow and ice cover revealing the darker ground beneath allows more solar heat energy to be soaked up. Melting of permafrost releases carbon dioxide and methane. These and other feedbacks serve to amplify the warming effect, speeding it up.

However, our burning of fossil fuels has happened on such a vast scale that we have blown such factors apart. The atmospheric concentration of CO2 has risen well above the 180-280 ppm range typical of recent glacial-interglacial cycles. The current level, getting on for 420 ppm, is more typical of the mid-Pliocene. That was a geological epoch that happened around a million years before the start of the Quaternary. Mid-Pliocene ice-sheets were much smaller than those of the present day. Rather than being due another glaciation, we can expect a continued transition towards mid-Pliocene conditions.

Please use this form to provide feedback about this new "At a glance" section, which was updated on May 27, 2023 to improve its readability. Read a more technical version below or dig deeper via the tabs above!

Further details

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? No.

To explore this topic further, it is necessary to understand what has caused the cyclic shifts between ice ages and interglacials during the Quaternary period (fig. 1). Such shifts are in part a response to regular changes in the Earth’s orbit and tilt, which affect the amount of summer sunlight reaching high northern latitudes and were described by the Milankovitch Cycles, first proposed in the early 20th Century by Serbian mathematician Milutin Milankovitch (1879-1958). For more about Milankovitch cycles this NASA page offers lots of graphics and explanations.

Figure 1: Temperature change through the late Quaternary from the Vostok ice-core, Antarctica (Petit et al. 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.

When incoming sunlight declines in the high north, the rate of summer snow and ice-melt declines and the ice sheets begin to grow. When incoming sunlight increases, the opposite happens. So where are we in these cycles today? Changes in both the orbit and tilt of the Earth do indeed indicate that – were they singularly responsible for climate shifts - the Earth should be slowly cooling. However, recent research shows that is too simple. That's because we now have analyses of ice-cores going back 800,000 years or more. We have devised ways to use stable isotope ratios of various elements in things like fossils and we have developed many other proxy methods for telling us more about conditions in the relatively recent past that the Quaternary represents.

A number of irregularities in glacial-interglacial cycles have been determined, for example times when interglacials were skipped when orbital patterns suggest they should have happened. (Koehler and Van de Wal 2021). Such research has also been aimed at resolving the question of why Earth's 41,000 year obliquity cycle was a strong driver of glacial-interglacial transitions up until around one million years ago. Since then, glacials have instead typically lasted for much longer - around 100,000 years.

The importance of feedbacks within Earth's climate system has been increasingly recognised as the decades have gone by. A good example is the speed of transition from glacial to interglacial, which is relatively rapid because certain very effective climate feedbacks are involved. One such feedback involves albedo, defined as the ability of different bodies to absorb or reflect sunlight (e,g, Thackeray and Fletcher 2016).

Albedo is expressed on a scale of 0 (black body, absorbs everything) to 1 (white body, reflects everything. Fresh snow has a high albedo of as much as 0.9, whereas the muck revealed when old snow and ice cover melts has a much lower one in the range 0.2 to 0.4 – it can absorb lots more solar energy. So melting snow and ice leads to more heat energy retention, amplifying the warming (Fig. 2). 

Albedo Explainer (John Mason)

Fig. 2: Albedo feedback explained. Freshly-fallen snow is highly reflective of incoming sunshine, so that most of the solar energy is simply bounced back towards space. Bare sea ice can potentially absorb about half of the incoming energy, so if conditions become warmer, causing the snow to melt, there’s more energy retained on Earth. If the sea ice melts too, then almost all of the incoming solar energy is absorbed by the much darker surface of the sea. So an initial warming directly results in further warming. Graphic: John Mason.

Another feedback happens when permafrost gets thawed out, since the ground is then able to release previously trapped CO2 and methane. During a glacial, the extent of permafrost is vast, so as it thaws, the release of such gases occurs on an enormous scale – again, amplifying the warming.

Researchers have also modelled ice-sheet dynamics, investigating how the sheets behaved as they melted, for example. It has been found that the shorter-lived, lower latitude Northern Hemisphere ice-sheets that existed prior to one million years ago were much thinner and therefore easier to melt. So ice-sheet dynamics looks to have a role in the much longer freeze-ups of the past million years. This all goes to show that glacial periods arise through a whole lot of factors interacting with one another, of which orbital cycles are but one, albeit important, cog in the gearbox and are not necessarily able to drive the climate system from one state (glacial) to another (interglacial) in total isolation (e.g. Bintanja and Van de Wal 2008; Berends et al. 2021).

Talking of cogs in the gearbox, we are another – and a big one. Our intentional disturbance of carbon reservoir rocks – what we do when we seek, extract and burn the fossil fuels – is unique in the geological record. It's a one-off in the planet's 4.56 billion year long history and while the consequent overloading of atmospheric CO2 levels is still insufficient to take Earth back into a Hothouse state yet, it is perfectly adequate to prevent another glaciation any time soon.

Last updated on 27 May 2023 by John Mason. View Archives

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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:


Denial101x video


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Comments 76 to 100 out of 168:

  1. @Tom: I'm not sure you understand what "anecdotal" means. In any case, there is no indication we are about to enter a very cold period. There were more heat records broken than cold records last year. The warming trend is strong, and shows no sign of reversing. Glacial periods are most likely the results of Milankovitch cycles, not of delicate "tipping points" that would be reached by increasing heat. You don't seem to be making much sense, I'm afraid.
  2. Ah, me thinks the idea of Milankovitch cycles borders on blaming astrology for the ice ages. There is a much better explanation and it is lighting up the skies over both hemispheres ever more with each year.
  3. Tom Loeber writes: Ah, me thinks the idea of Milankovitch cycles borders on blaming astrology for the ice ages Please don't be a troll. The association between Milankovich geometry and glacial/interglacial cycles is very, very well established. The mechanisms by which this works are not completely understood, but we do know a lot about it. The very short version is that a reduction in seasonal insolation during high-latitude Northern Hemisphere summers allows snowpack to persist through the summer, leading to the inception of ice sheets. When summer insolation around 65 North begins increasing again, this process reverses itself. If you don't understand how this works, check out Bill Ruddiman's textbook (Earth's Climate) or David Archer's eminently readable book (The Long Thaw).
  4. Oh, don't get me going on the widespread cold in the northern hemisphere... Agreed, it's apparent there would be little point in that, so please don't start. Clearly you're not a fellow to be swayed by collated data permitting of useful conclusions, meanwhile the strong preference here is to stick w/exactly that sort of information.
  5. @TL: "Ah, me thinks the idea of Milankovitch cycles borders on blaming astrology for the ice ages." Cute. Completely wrong, but cute. "There is a much better explanation and it is lighting up the skies over both hemispheres ever more with each year." TSI has been going down, and we are past the Holocene Climatic Optimum. If it was up to natural cycles, we should be cooling, not warming up.
  6. Tom Loeber, there was no "widespread cold in the northern hemisphere over the last couple of years", just as there has been no "widespread record cold" over the southern hemisphere more recently. You would save yourself a lot of bother if you look into the facts and figures of these situations, rather than rely on exaggerated and over-the-top headlines, especially those from the likes of ICECAP.COM.
  7. My understanding is that when Milankovitch first proposed his theory he suggested gravitational influences from stars other than our own play a part in the comings and goings of ice ages besides eccentricity of orbit, influence of other planets, etc.. That seems pretty outrageous to me, tantamount to astrology. BUT that theory totally absolves humanity from having to watch what it does to the atmosphere as far as avoiding the threat of tipping the climate into its most stable state, ice age conditions. Most likely people reading this have college and university experiences. Look at who provides scholarships, awards and "prizes" more than any other source of money. It is the fossil fuel and the otherwise military associated companies that play a major role in determining funding, who gets degrees, who gets well paying jobs and who gets to be teachers. Do you think this does not lead to across the board mistaken assumptions that downplay the danger of burning fossil fuels? The way I have come to describe it, the interglacial is like a house of cards. It takes a long time to build but can collapse fast. The Hamaker hypothesis appears to fit the evidence better than the Milankovitch theory. Unlike the Milankovitch theory, the Hamaker hypothesis has led to experiments that strongly suggest its relative validity, real time experiments. The Hamaker hypothesis is not just dependent on the interpretation of past events like the Milankovitch theory is, solely. Many small and large scale experiments show soil remineralization greatly increases biomass and carbon dioxide sequestering. The Milankovitch theory does not explain noctilucents. They get in its way so I see, such as in the following article they are ignored, not even mentioned, though earth albedo is found to be the driving factor and not solar insolation Interglacials, Milankovitch Cycles, and Carbon Dioxide 2/10 Scientific understanding has been found to be quite wrong before despite a vast majority of established scientists, teachers, lecturers, politicians etc. holding most vehemently to the mistaken assumptions. It is even more easy to have those mistaken assumptions when they absolve any danger of the promulgation of the main money making enterprise of the richest fraction of the population. Noctilucents, a fly in your ointment, gentlemen.
  8. Mr. Murphy, there is so much. The record cold that destroyed the livelihood of Mongolian herders, killing their livestock, the record cold across the whole south of China that was said to be the worst in more than 700 years, the record cold and snow in Washington state and descending into Oregon that helped kill my mom two years ago. The NE US and Europe cold that Professor Hansen explained away as weather not climate. England is stated as having their coldest winter on record within the last two years. I could give you a list as long as my arm of record cold events, widespread and on all continents and it appears since they just don't fit your hypothesis you can't see them. It is my opinion that the greatest danger we face is epistemic relativism. Might does not make right. Majority opinion does not determine truth. Observe to formulate opinions ad infinitum. Don't opinionize to formulate what you can and cannot observe.
  9. The Milankovitch theory does not explain noctilucents. They get in its way so I see, such as in the following article they are ignored, not even mentioned... Tom, if you'd actually read replies to your comments, you'd already have learned that noctilucent clouds are not being ignored. A further two minutes w/Google Scholar would also help you realize that the flies are actually in your ointment, screaming with their tiny voices for your attention.
  10. Tom #82: Noctilucent clouds are believed to be CAUSED by global warming... and thus hardly constitute a 'fly in the ointment'. From what I can gather I think you are arguing that noctilucent clouds indicate cooling and thus are contrary to global warming. Of course, noctilucent clouds are found in the mesosphere... which of course cools as greenhouse gas concentrations increase and 'trap' heat in the lower atmosphere.
  11. Tom Loeber - There will always be some extreme weather with unfortunate consequences, including the events that affected your family (which I'm very sorry to hear about). However, singular events are weather. If you are looking at climate (long term trends), you need to look at the statistics and numbers of many events, hot and cold. If you look at the relative numbers of hot and cold events, maxima and minima, you will see that individual cold weather doesn't disprove global warming. There are simply more extreme highs than extreme lows over the past 30 years. What we personally experience has strong effects on our beliefs - how could it not? But if you want to look at global changes, you need to look beyond personal direct experience to the global data.
  12. I've just looked up that Hamaker fellow and it appears he was predicting a shortening of growing seasons, before we fall head-long into an ice-age. Any proof ? An increasing number of studies have reported on shifts in timing and length of the growing season, based on phenological, satellite and climatological studies. The evidence points to a lengthening of the growing season of ca. 10–20 days in the last few decades, where an earlier onset of the start is most prominent. Observed changes in growing season length Field and satellite data at the community and biome levels indicate a lengthening of the growing season across much of the Northern Hemisphere (1–6) and—where data exist—in the Southern Hemisphere (5, 7, 8), yet life history observations of individual species suggest that many species often shorten their life cycle in response to warming (9–12). Not a very good start for Mr Hamaker, it would appear...
  13. KR, extreme weather but over wide areas of the planet? When extreme weather becomes the norm should we still discount it? I am not denying global warming. I do think if the planet does snap into ice age conditions that will be a singular event and it will be climate and weather. I think there is a great deal of evidence that is happening but seems most are going to have to learn the hard way and that means a lot of death and destruction, maybe too much for humanity to survive, IMHO.
  14. Mr. Murphy, no one is perfect. John Hamaker was apparently totally unaware of noctilucents though they appear to be a very strong indication that his theory is largely sound. Did you get a chance to see that movie I linked to earlier? Those small and large scale experiments in remineralizing soils offers so much to help us secure this planet. How come it is not a UN sponsored strategy? Seems remineralizing soils rather than using fossil fuel derived fertilizers would help the situation no matter what theory you believe. Hmmm, could fossil fuel companies wanting their cash cow of fertilizers to remain unchallenged be playing any role?
  15. Tom Loeber wrote : "Mr. Murphy, there is so much. The record cold that destroyed the livelihood of Mongolian herders, killing their livestock, the record cold across the whole south of China that was said to be the worst in more than 700 years, the record cold and snow in Washington state and descending into Oregon that helped kill my mom two years ago. The NE US and Europe cold that Professor Hansen explained away as weather not climate. England is stated as having their coldest winter on record within the last two years. I could give you a list as long as my arm of record cold events, widespread and on all continents and it appears since they just don't fit your hypothesis you can't see them." Firstly, last Winter here in the UK was the coldest since the late 70s overall. Hardly the "coldest winter on record". Feel free to post evidence that shows otherwise. Mongolian herders were indeed affected by a very cold Winter following the previous season's drought - a double whammy, as some of your other news articles for other countries have shown. Record cold ? Only if you want to believe so. I have read news articles about the cold Winter in China, a couple of years ago, suggesting the coldest since anywhere between 20 to 100 years. 700 years ? Over to you. You are still relying on news outlets for your opinions, but also, it would appear, your own personal loss. I can understand how this would make you want to see everything in catastrophic terms.
  16. Tom, With respect, you are simply not listening or comprehending the replies to your posts. You keep citing cold weather events, that is confirmation bias. I'll repeat it again, only one nation around the globe has set all time record cold low in 2010. In contrast, so far this year 17 nations around the world set all time high records, and 2010 is on track to be the warmest on record. In the USA warm temperature records are out pacing cold records by over 2:1 so far this year, and similar stats are emerging elsewhere. We are not rapidly changing the tilt of the earth's axis Tom, there are still going to be seasons, including cold snaps during the winter months. The long term trend is global temperatures is up, and for the past 30 years the planet has been warming at almost 0.2 C/decade. The cold weather in parts of Europe and Eurasia last winter were because of the Arctic Oscillation (internal climate variability) flipping into an extremely negative phase, which meant the Arctic was relatively warm while the aforementioned areas were colder than average (not all time record lows as far as I can tell). Sorry, but unless you up your game and stop moving the goal posts, I'm tuning out.
  17. Mr. Bostrom, so if the data does not lead to "useful conclusions" it should be ignored or discounted totally? I've yet to go into all the links you provided but that last one, he shows a graph of 45 years and determines that noctilucents are really of no concern. Hmmm, first surface mirrors peaking at summer when solar input is supposed to be the most coating the planet far above the green house gases not a concern? How about this graph from NASA going back to when noctilucents were first recorded. I think that tends to skew the data presented in the paper you link to towards a different conclusion. My understanding is that over the last few years the noctilucents have grown in frequency and duration to record amounts repeatedly, beating practically each year's extent and duration.
  18. Tom Loeber, noctilucent clouds = cooling mesosphere = warming surface. For example; Summer: Warm at the surface. Cold in the mesosphere. Poles: Showing the greatest surface warming. Coldest region of the mesosphere. Increasing CO2: Warms the surface. Cools the mesosphere. Noctilucent clouds require temperatures of about -120 C to form... which even the mesosphere, the coldest region on Earth, seldom reaches. That is why they are seen in Summer near the poles... the coldest time and region of the mesosphere. As CO2 concentrations increase the mesosphere as a whole gets colder and noctilucent clouds become more common, but the planet's surface gets warmer. Your premise seems to be 'as goes the mesosphere so goes the planet'. In reality all available evidence indicates the opposite... a cooling mesosphere means a warming planet.
  19. Mr. Albatross, thank you for posting your name. Only one nation? That is not worthy of any effort to refute. It is you being highly unreasonable and inaccurate. I am warmed by your deciding to tune out. I see that you folks pretty much have your minds made up and no amount of contrary evidence can be tolerated. I expect to be banned or something like that soon, eh?
  20. No, Tom. It's almost impossible to be banned here. You can expect to be ignored.
    Response: Also, Tom, individual comments will be deleted if they are off topic of the page on which they are posted. You need to continue discussion of individual weather events on the relevant thread It’s freaking cold!.
  21. Tom, Please read this Those are actual weather data form various weather agencies and climate groups around the world. You continue to fail to support your assertions with facts and data. And a correction to my previous post. No nations have set record cold temperatures in 2010, not one: "No nations set record for their coldest temperature in history in 2010. Jeff Masters erroneously reported in his blog earlier this year that Guinea had done so. Guinea actually had its coldest temperature in history last year, on January 9, 2009, when the mercury hit 1.4°C (34.5°F) at Mali-ville in the Labe region." [from above link] "I expect to be banned or something like that soon, eh?" John Cook is very patient and open to criticism, and you'll find that is you can support your arguments with facts, people here will be very tolerant. That said, this site has a comments policy and you seem to be doing your best to break the rules and antagonize people, why? Again, time to up your game and start substantiating your claims with facts from reputable sources, this may be a blog, but it is a science blog.
  22. Tom Loeber - I don't believe you'll be banned; I don't know of anyone who has, quite frankly. However, your arguments about noctilucent clouds are (as CBDunkerson pointed out, reversing the causal relationship - more noctilucent clouds are expected with warming, not fewer. Extreme weather conditions are to be expected with natural variability - but extreme maxima are occurring twice as often as extreme minima over the last few decades. Your insistence on scattered news reports and anecdotes does you no favor in this discussion - the data contradicts you on that. And as per the main topic of this thread, we appear to be moving away from ice age conditions, when normal cycles indicated we should be moving towards an ice age - we're getting further from ice age conditions all the time. You have presented roughly zero evidence for an immanent ice age. So, while I don't know if anyone gets banned (although individual posts get cut, and if someone has nothing but insults or off-topic posts, it may seem that they're cut), you are at this point not going to be taken seriously by anyone on this site unless you develop a more evidence-based line of discussion. Not banned. Ignored, I'm sorry to say, is fairly likely. I would really encourage you to look at and consider the evidence for global changes (watching out for confirmational bias), and remain in the discussion.
  23. Tom Loeber wrote : "I see that you folks pretty much have your minds made up and no amount of contrary evidence can be tolerated. " Unfortunately, you have no "contrary evidence" : you have newspaper articles, online news stories, personal theories and personal experience. Doubly unfortunate is that you cannot see that you don't have any "contrary evidence". If you don't actually provide any, you can indeed expect to be ignored or repetitively shown the evidence that has already been shown but which you are ignoring because you have a pre-determined need to believe what you want to believe. Provide some real evidence, please.
  24. Tom #94: "Only one nation? That is not worthy of any effort to refute." Why? It would be so EASY to prove that you are right. Especially since in post #96 Albatross says it turns out that "one country", Guinea, actually had its all time record set LAST year. So all you have to do is cite one country, anywhere in the world, which had its all time record coldest temperature set this year. Just one. That's really 'too much effort'? After all the other posts you've made? Typing out the name of a country is too much work? Or is it not worth refuting... because it is TRUE?
  25. Tom: "I see that you folks pretty much have your minds made up and no amount of contrary evidence can be tolerated." Tom, you know the same could be said of you. You simply don't (or choose not to) recognize that in terms of amount, the evidence against what you claim is mountainous compared to your molehill's worth. I'd like to see the mechanism you propose that would cause a sudden cooling snap (no global instrumental temperature record displays a cooling trend excepting TOA). Can you model the tipping point for us? How long do we have? Or are you simply picking over the mass of collected data and choosing the bits that support your "shocking" pseudo-theory?

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