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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)

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 1 to 25 out of 82:

  1. Hi John: Thanks for the thanks (although I will hasten to point out that all I did was offer some minor comments). I am especially delighted to me mentioned in the same acknowledgement as Dr. Solanki. I don't know if Dr. Solanki reads this blog, but if he does I would like to say that I have been reading his papers since I came across the Harold Jefferys Lecture that he did about 4 years ago. Very interesting work! Regards, John
  2. Re: "What if the sun did go through another Maunder Minimum?" Not IF but When. It's part of the long term climate cycle.
  3. Actually we can't head into an ice age at this point in time because we are already in one. Technically this is an interglacial period within the current ice age, ie. this is not "Earth Normal" climate, which is much hotter. Interglacial means "between glacations" and is about as unstable a climate as possible on this planet. That is assuming that it is an interglacial rather than the ice age ending (far worse for us). It also assumes that another glacation will occur. Looking at graphs of prior interglacials and glacations there is a particular constant: it warms slowly for thousands of years then cools rapidly (it looks very similar to a sawtooth inventory graph). Another fact is that CO2 has been very high when it suddenly became very cold (it did nothing to stop the glacations). So be afraid, be very afraid.
  4. Quietman: That's simply not true. The glacial cycles of the last 450'000 years have consisted of long periods of slow cooling, followed by rapid warming. (http://commons.wikimedia.org/wiki/Image:Ice_Age_Temperature.png - please note that present day is to the left). This rapid warming is believed to be started by small changes in solar forcing (see Milankovitch cycles: http://en.wikipedia.org/wiki/Milankovitch_cycles) which is enough to start positive feedback spirals: warmer -> more greenhouse gases -> even warmer... Since we've recently come out of an glacial period, temperature is basically is as it gets and should be slowly decreasing (on a long timescale) until we reach the next glacial period. But instead, anthropogenic releases of greenhouse gases have started the process of warming. The amount of released GHG so far is enough to keep the planet warming for a long time (but of course, with possible micro trends of cooling) and we've soon reached a level where positive feedback spirals kick in, meaning that temperature will continue to rise even if we would stop our own releases of GHG.
  5. should've been: "... is basically as high as it gets ..."
  6. Maunder minimum...solar radiation ( and I deliberately use that term) drops between .17 and .23 W/m2; the suggestion is that these changes are insufficient to account for glaciation periods, or , if they are responsible, the system must be pretty thermally unstable. What was perihelion at this time? Orbital eccenticities have FAR greater effects on the amount of radiation recieved (between 6 -7% depending on source)than solar variations. What other factors were different then as opposed to now? You cannot isolate one component of a system and use it to determine an end result. You have to include all factors. My general conclusions from what I have read and what I have tried to model, is that the 'normal' state of the earth is "cold". That the warm phases are the anomalies. I accept this is MY opinion, but given the choice between a longer, warmer interglacial period or an earlier decline into one, I think I would opt for the warmth; life ( of all kinds) flourishes better in warm climates
  7. Why am I not surprised that the snapshot used by "Image from Global Warming Art" is different from everyone elses? It's called cherry picking.
  8. To clarify, Look at the 5 million year chart instead. The highs and lows of 450 K years are only oscillations of a gradual warming trend for 5 million years.
  9. The O18 concentration in bottom-dwelling foramanifera is used as a proxy for surface climatic conditions: eg a warmer climate produces more dead bodies drifting to the sea bed which allows the organisms there to multiply and 'trap' more O18. There are some difficulties with this, namely, you need prior data on the level of O18 or C13 at 'ground zero'. Also how do you compute the time lags involved? Slide the graph around until there seems some kind of match to glacier records? How do you accomodate variations in surface species numbers due to local climate? Are 57 core samples sufficient to give a general trend? http://en.wikipedia.org/wiki/Paleothermometer
  10. "The difference in solar radiative forcing between Maunder Minimum levels and current solar activity is estimated between 0.17 W/m2 (Wang 2005) to 0.23 W/m2 (Krivova 2007)" Wang 2005: "The increase in cycle-averaged TSI since the Maunder minimum is estimated to be ~1 W/m2" (instead of 0.17 W/m2?) Krivova 2007: "[The model predicts] an increase in the solar total irradiance since the Maunder minimum of 1.3^+0.2_-0.4 W/m2" (instead of 0.23 W/m2?)
  11. I am a novice here but I have noticed a lot of technical jargon that I don't understand. "Al Gore" etc thinks it is going to get warm. The "skeptics" say it is going to get cold. I think that if I lived in the NH I would make sure I have got some warm clothes. The bottom line is that all our heat comes from the Sun. If it cools down so does Earth. Any variances due to different Ocean Currents, Magnetic Fields etc are only releasing stored energy from the Sun. At the end of the day this planet will be a Dead Rock circling a spent Sun. Lets hope it warms up, CO2 increases, Plants grow and life becomes comfortable for a while. The alternative is not nice.
  12. Nor is a seven metre rise in sea levels. Where are all the people who live within ten miles of the coast going to live? I doubt the dinosaurs worried too much about how much land they had available or how many times they were flooded out or how many died in forest fires or died of thirst.
  13. Samboc: Don't worry about the sun cooling down just yet, providing it doesn't do anything silly it will follow the normal sequence for its type and increase in luminosity ( by about 10% over the next billion years). And you're right: warmer is better as the paleorecord shows. The view that sea levels will rise to the levels predicted is based on assumptions, not facts. All that water has to come from somewhere- snow,glaciers, icecaps, thermal expansion et al. There are many unresolved factors such as land rebound, greater oceanic uptake of CO2 due to rising ocean volume decreasing the GG efect at the same time as ocean warming releases more CO2...and one can go on and on. We currently simply do not have the ability (or data)to fully understand and accurately model the climate process, so it is not reasonable to take action that would have severe economic and societal repercussions until that time arrives.
  14. Samboc Well said. Warm is better than cold.
  15. sandy Distance to the shore is irrelevant, height above sea level is relevant. But a small factor is left out when the alarmists talk about sea level rise and that is porosity and absorbtion. The Newark Basin in New Jersey is not very much higher than sea level and yet it was swamp lands during the mesozoic, not ocean bottom. Much of the coast that will flood is swamp land now. During the Mesozoic the midwestern US was an inland sea and remains lowland today. A catastrophic rise in sea level will most likely result in a return of the inland sea, something that alarmists fail to mention.
  16. On sea levels: In Australia a bed of semi-fossilised molluscs has been found above current sea level and dated at between 4500 to 6000 years old. This suggests current MSL has fallen over the last 6000yrs. since Australia is not very active tectonically. Wait til the creationists find that one! I can't remember the exact page but more detail is at John-Daly web site.
  17. Mizimi Plates literally float. They can shift, rise or fall. There are no true continents, what we see is a result of large pieces of lighter material breaking and mergeing or subducting. There is no real difference between sea floor and land other than elevation. So while Australia is relatively free from volcanism it is still subject to plate tectonics which are constantly active but change intensity and speed is cycles.
  18. QM: Yes, and it makes rather a nonsense of trying to assign mean sea level deviations to global warming. The Isles of Scilly is a group of around 50 islands some 45km south west of Cornwall, England. They have been inhabited since (at least) the bronze age, some 4000ya. At low tide, stone houses, roads and field perimeters are revealed, dating from that time, so either msl has risen a few metres in 4000yrs or the islands have sunk.....how to tell the difference?
  19. Mizimi I think Dr. Rhodes Fairbridge answered that question in his study of sea level cycles. It's referred to as the "Fairbridge curve" and I think wikipedia posted an explanation of how it works. I have not looked too deeply into it as I am more interested in his later "Solar Jerk" hypothesis.
  20. I heard about this on the radio last month, and this would prove that we are not the cause of climate change, and that industrialization is not harmful. Unfortunately, many people are still advocating global warming since they have their money on it. This seems to be the strategy for defense of these advocates: "if any part of the earth gets warmer during the industrialized age, industrialization is to blame. If the earth gets cooler, of course, industrialization is a bad thing anyway. Heads, I win. Tails, you lose!
  21. QM: have you read this, and if so, any comment? http://www.griffith.edu.au/conference/ics2007/pdf/ICS176.pdf How's the greehouse project?
  22. Mizimi Yes that was the first piece I saw that got me interested in the hypothesis. Mackey said the test period would be 2007-2011 and so far it's on the money. It's also the ONLY paper that predicted the cold snap, all the other articles and papers at that time said exactly the opposite. (I kept all the failed forcasts in a file to serve as bad examples for future generations). ps The green house is on hold until the ice melts. Right now I'm waiting on delivery of a larger snow blower that I can mount off the PTO on my tractor. Snow has been way too heavy for the gas fired one and too deep to plow, I have been using a bucket loader all winter to shovel it off and it's ruining my driveway. So I'm going to have to resurface it when everything finally melts. But I am planning to go with the blue plastic for the roof.
  23. John "We're heading into a new Little Ice Age" equals "It's the Sun". No different, same thread.
  24. SAME THREADS: "Are Sunspots Different" http://www.leif.org/EOS/2009EO300001.pdf "LONGER TERM SOLAR MINIMUM" http://icecap.us/images/uploads/SOLAR_MINIMUM.pdf
  25. [quote]The difference in solar radiative forcing between Maunder Minimum levels and current solar activity is estimated between 0.17 W/m2 (Wang 2005) to 0.23 W/m2 (Krivova 2007).[/quote] Solar radiative forcing is not the only change to account for. Solar minimum may also mean less solar wind and solar cosmic rays and geo-magnetic interaction. There is a correlation between solar cycles and the number of galactic cosmic rays, wich can cause more or less cloud formation that can increase the albedo reflecting a significative part of the total sun power. So when we talk about a solar cycle influence we should include also this issue.

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