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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.

Acknowledgements

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:

 

Comments

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Comments 276 to 300 out of 410:

  1. As a followup to my previous comment, real scientists doing real studies have already looked into whether the Earth will warm or cool, long-term. As opposed to empty assertions, let's examine the facts, shall we:

    Per Tzedakis et al 2012,

    glacial inception would require CO2 concentrations below preindustrial levels of 280 ppmv

    For reference, we are at about 394 right now…and climbing, so we can be relatively sure the next glacial epoch won't be happening in our lifetimes.

    But what about further down the road? What happens then? Per Dr Toby Tyrrell (Tyrrell 2007) of the University of Southampton's School of Ocean and Earth Science at the National Oceanography Centre, Southampton:

    "Our research shows why atmospheric CO2 will not return to pre-industrial levels after we stop burning fossil fuels. It shows that it if we use up all known fossil fuels it doesn't matter at what rate we burn them.

    The result would be the same if we burned them at present rates or at more moderate rates; we would still get the same eventual ice-age-prevention result."

    and

    "Burning all recoverable fossil fuels could lead to avoidance of the next five ice ages."

    So no ice ages and no Arctic sea ice recovery the next million years...

    Facts, like Tiggers, are wonderful things, for those who have them.

    Also covered by Stoat, here.

    Given the radiative imbalance at the TOA is still present and that CO2 levels are still increasing (and that human emissions are not ending anytime soon), it is reasonable to presume that the impacts of a warming planet will increasingly impact the most vulnerable aspects of our remaining cryosphere: the Arctic sea ice (a goner), the Greenland Ice Sheet and the West Antarctic Ice Sheet.

    We are, through our own actions, effectively locking-in a world of another 8-12 meters SLR above present. Unless we can magically arrest our emissions and also initiate methods to draw-down atmospheric concentrations of CO2.

  2. Kevin You might find this paper interesting, the question of the regularity of glacials is apparently not quite as straightforward.

    As to the question "Who decided that the temp after the industrial revolution was the "accurate" temperature the earth should be at, and that we are exceeding that perfect temp?", that really is a canard that has been answered here repeatedly.


    A reasonable answer to that would be "the perfect temperature of the Earth is that to which our civilisation (and especially agricultural practices) has become highly adapted".  It is the change in climate that is the principal problem, as adapting to change has costs. It seems likely that mitigation will reduce the cost of adaptation, so that would appear to be the rational strategy. It isn't rocket science.


    Do you accept that answer?

  3. A reasonable answer to that would be "the perfect temperature of the Earth is that to which our civilisation (and especially agricultural practices) has become highly adapted". 

     

    OK.  But then, the LIA was quite cold, and people adapted, agriculture adapted, but at cost (which is part of your point - in other direction but applicable).  During the Roman optimal, wine grapes were grown in Great Britain.  During the Medieval Warm period, grains were reported to be much more bountiful. 

     

    On another note, how is it that you were able to respond to my post, yet my post does not appear?

  4. the appearance issue was regarding my second post, sorry about that.

  5. "During the Roman optimal, wine grapes were grown in Great Britain"

    Prove it.  We await the links to the reputable sources.

  6. Kevin There are plenty of historical precedents for civilisations not surviving climate change (e.g. Egyptian Old Kingdom).  At the time of the LIA, global population was much lower, and agricultiral land less over-exploited, which made adaption very much easier than it is now.  There are large parts of the world that are relatively poor, where large populations exist with marginal subsistence agriculture.  Adapting for us will be much easier than it will for them.  There is also the point that the rate of change is also relevant to adaption.  Even then the LIA caused great hardship for many, the natural climate change we can do little about, but that doesn't make it O.K. to cause some more for ourselves.

    The point is that questioning whether there is a perfect temperature for the Earth is a straw man - nobody is claiming that there is one, and it isn't really relevant anyway, it is the change that is important. 

    Now if you have evidence to show that we will have no problem adapting to the projected climate change, then I am sure there is a relevant post at SkS on which to discuss it, but this isn't it.

    The post to which I responded is still there (at least I can still see it).

  7. Kevin:

    Wine production appears to have been more-or-less continuous in the UK since the Roman invasion, albeit patchily implemented at commercial scales and vulnerable to sociopolitical changes.

    As far as I am aware (courtesy of a survey of the Met Office and Environment Canada sites), the UK, and in particular southern England, has had, for some centuries, a climate that is comparable to current wine-growing regions in southern Ontario and British Columbia, despite being at a comparatively higher latitude.

    IMO the significance of Roman viticulture in the UK is overstated in the context of climate change discussions.

  8. While England had 42 vineyards at the time of the Domesday Book, as is well known, there are now over 300 commercial English vineyards today.  So the climate today in England is much more conducive to wine-making than during the Roman occupation of England, consistent with the proxy reconstructions of temperatures covering those times.
    http://www.english-wine.com/vineyards.html
    http://www.englishwineproducers.com/history.htm

    Last 2,000 years

    [Source]


    Without a link to a source for that claim I must conclude that Kevin just made that claim up. Especially given that it took me all of 3 minutes to look up the material for this comment...and that Kevin has had more than 4 hours to do likewise...

  9. Also apparent from DB's graph, is that rate of temperature change (which strongly influences our ability to adapt) is much faster now than going into the LIA.  Accounts of the time suggests adapting to LIA wasnt all beer and skittles either. I'd rather avoid that kind of pain and paying more for my energy is certainly acceptable. We adapted pretty well to change in oil price to $15 to $80 and projected energy change costs not in that league.

  10. Kevin:

    1)  Figure 4 of the intermediate version of the above article shows expected future temperatures based on milankovithch cycles and CO2 concentration.  Even by eyeball it is evident that at preindustrial CO2 levels, no new glacial is imminent for thousands of years.

    2)  I will see you your "wine in England", which as Daniel points out, is a very current phenomenon, and raise you three vinyards in Scotland (one indoors), and four commercial vinyards in Sweden!   I will note that traditionally grapes were grown in England not because they produced good wine, but because wine was needed for sacramental reasons, and until recently, wines turned to vinigar if transported any distance.

  11. DB @ 280:

    "It is said that Julius Caesar brought the vine to England. Nice though that story is, some scholars think it apocryphal - wine was certainly brought to Britain by the Romans, but it is less certain whether the vine was grown here, or if it was, whether it was in sufficent quantity to satisfy the local requirement for wine or just as an ornament to remind Romans of home and wealthy Romano-Britons of the source of their civilisation and prosperity."

    (Source)

  12. Here is a source for wine in UK CfA Press Release
    Release No.: 03-10
    For Release: March 31, 2003 20th Century Climate Not So Hot

    Cambridge, MA - A review of more than 200 climate studies led by researchers at the Harvard-Smithsonian Center for Astrophysics has determined that the 20th century is neither the warmest century nor the century with the most extreme weather of the past 1000 years. The review also confirmed that the Medieval Warm Period of 800 to 1300 A.D. and the Little Ice Age of 1300 to 1900 A.D. were worldwide phenomena not limited to the European and North American continents. While 20th century temperatures are much higher than in the Little Ice Age period, many parts of the world show the medieval warmth to be greater than that of the 20th century.

    Smithsonian astronomers Willie Soon and Sallie Baliunas, with co-authors Craig Idso and Sherwood Idso (Center for the Study of Carbon Dioxide and Global Change) and David Legates (Center for Climatic Research, University of Delaware), compiled and examined results from more than 240 research papers published by thousands of researchers over the past four decades. Their report, covering a multitude of geophysical and biological climate indicators, provides a detailed look at climate changes that occurred in different regions around the world over the last 1000 years.

    "Many true research advances in reconstructing ancient climates have occurred over the past two decades," Soon says, "so we felt it was time to pull together a large sample of recent studies from the last 5-10 years and look for patterns of variability and change. In fact, clear patterns did emerge showing that regions worldwide experienced the highs of the Medieval Warm Period and lows of the Little Ice Age, and that 20th century temperatures are generally cooler than during the medieval warmth."

    Soon and his colleagues concluded that the 20th century is neither the warmest century over the last 1000 years, nor is it the most extreme. Their findings about the pattern of historical climate variations will help make computer climate models simulate both natural and man-made changes more accurately, and lead to better climate forecasts especially on local and regional levels. This is especially true in simulations on timescales ranging from several decades to a century.

    For more information, contact:

    David Aguilar, Director of Public Affairs
    Harvard-Smithsonian Center for Astrophysics
    Phone: 617-495-7462 Fax: 617-495-7468
    daguilar@cfa.harvard.edu

    Christine Lafon
    Public Affairs Specialist
    Harvard-Smithsonian Center for Astrophysics
    Phone: 617-495-7463, Fax: 617-495-7016
    clafon@cfa.harvard.edu

    Response: [DB] Further to DM's comments below, your claim also pertained to the Roman optimal, not the Medieval Warm Period. Try again.

    [Sph] Original comment edited to correct formatting issues.
  13. Kevin, that is not proof, Bauliunas says that vinyards flourished in England, but that doesn't make it true.  Is there evidence in the paper on which the press article was based?

    BTW you do know that Energy and Environment is not a science journal, but a social sciences journal, don't you?

  14. DM, you're being generous.  Kevin might want to take a look at some of the other studies that E&E has published.  

    Kevin, you might also look at the Soon & Baliunas (2003) affair, and also what Willie Soon is capable of trying to pull over on his target audience.  What a world it would be if fake skeptics gave the same level of scrutiny to those they pedestalize as they do to the studies that do not support their worldviews.  

  15. source for grain abundance is

    faculty.history.wisc.edu/sommerville/123/123%2013%20Society.htm
    Response: [DB] Non sequitur. The Domesday reference does not cover the period in question nor is there any references to wine or vineyards in the linked article. Try again.
  16. As far as I can see, that source provides no real evidence (references to primary sources?) and provides only rather equivocal support for your assertion, e.g.:

    "More people meant smaller acreage of land per person and this led to "harvest sensitivity." In years of poor harvests (such as the wet summers of 1315-1316) insufficient grain was grown and the poor starved."

    "English agricultural methods and productivity remained stagnant throughout the Middle Ages. The "strip" system of farming was equitable and extremely inefficient. Yields of grain per acre remained stagnant."

    "Food production was only increased by bringing more land under the plow - a process that stopped once all available waste land had been improved."

    Also the graph of population (reproduced below) suggests that a fair proportion of the population didn't adapt to the LIA (except perhaps by dying).


    Regarding grain abundance, your source emphasises a point I was making: "More people meant smaller acreage of land per person and this led to "harvest sensitivity." In years of poor harvests (such as the wet summers of 1315-1316) insufficient grain was grown and the poor starved." That sitation is far worse now in a world with 9 billion mouths to feed.  As far as I can see you have provided very little evidence to suggest that the past suggests we can adapt to future climate change without substantial hardship.

    Response: [DB] Nor does it cover his claimed time period of the Roman optimal.
  17. Here is one for the Roman Optimal

    www.english-wine.com/history.html

    The last source was for the Medieval Period, for grain.

    Response:

    [DB] It is noted that your referenced source does not support your earlier contention. Therefore, the conclusions reached in this comment apply and you tacitly agree to its conclusion:

    "So the climate today in England is much more conducive to wine-making than during the Roman occupation of England, consistent with the proxy reconstructions of temperatures covering those times."

    By agreeing, you concede you earlier comment was in error and therefore invalid. If you disagree, you will need to then further support it here before being allowed to comment elsewhere on this site.

  18. If I can end the game between Kevin and the Moderators, this is evidence of viticulture in Roman Britain:

    "This article presents stratigraphic and palynological data from Wollaston in the Nene Valley, England, which provides conclusive evidence of viticulture on an large scale. The spread of Viticulture through the Roman World and the extent to which it supplanted beer brewing can be seen as an essential element in the consideration of the Romanization of northwest Europe. The pollen assemblage suggests hoeing or ploughing was used, presumably to reduce grass and weed growth around the vines. The distribution of known and probable sites and of suitable pruning tools has a distinct southeastern bias, as might be expected from the spatial variation of climate in the British Isles."

    (My emphasis)

    So also does this article about the same site, but note that while "...the apparent lack of viticultural tools and wine presses in the archaeological record in Britain is not reliable evidence for the absence of viticulture at that time", it must be considered evidence that viticulture was not widespread.

    Regardless, as I have noted on other occassions, the presence or absence of vinyards is a poor proxy of climate as human and economic factors play too large a role.  Is the decline (but not absence) of viticulture in Anglo-saxon Britain and indication of cooler climates, or just an indication that the Anglo-saxons has a taste for ale in preference to wine?  Does the post norman decline in viticulture in England reprsent a decline in climate or the fact that improvements in wine manufacture and transport made French wine cheaper in Britain?

    More importantly, if you are going to use viticulture as a proxy for climate in the past, then you must be consistent and do so in the present.  So, if viticulture in England in Roman and Norman times is evidence of warm climates at that time, then viticulture in Scotland and Sweden now must be considered evidence that it is warmer now than in Roman or Norman times.  The extent to which deniers cherry pick data rather than following evidence is shown by their refusal to follow the clear logic of this argument.

  19. Dikran Marsupial @291, the very sharp decline in population in the 14th century has almost nothing to do with climate, and everything to do with the Bubonic Plague.  Much of the increase before that had little to do with climate, and much to do with the adoption of the horse collar in Europe.

  20. Kevin pretty much scored an own goal here.

  21. Tom, yes you are absolutely right about the cause of the decline in European populations, doh!  The info on English wine growing was also very interesting, ISTR there is something about it in the book on the British Climate compiled a few years ago, I think in honour of Hubert Lamb, but it is back in the library now, so I can't check. I hope Kevin learns from this exercise that perhaps his information on the topic of climate isn't perhaps all it could be, and will moderate the attitude in his posts somewhat.  We are all happy to discuss science here, but generally those who arrive with a bit of an attitude tend to provoke a correspondingly confrontational response.

  22. http://antiquity.ac.uk/ant/075/Ant0750745.htm

     

    Try this source for Roman Optimal Wine production n UK.

  23. Kevin, thanks for the link, it is a shame that the article is paywalled - it looks interesting (see also Toms comment).  Please do take on board my comments in the previous post.  We are happy to discuss science here, but you will get a much better reception if you make your points in a measured scientific, rather than a confrontational hubristic manner, especially as your previous comments suggest a lack of understanding of some important issues

  24. There is a free-access, text-only version of that paper available here

  25. Cheers Andy, very interesting, the differing standards of acceptable evidence in archaeology and climatology is very evident (of course this is inevitable and not an indication of a problem with archaeology)!

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