Anthropogenic Global Warming and Ice Age

Very shortly: Anthropogenic global warming is a trouble of the current and coming centuries. Ice ages are slower phenomena happening with thousand and tens of thousands of years time scales.

If there will be an ice age 100,000 years from now, it doesn’t remove the problem of global warming in 100 years.

I do not understand what is so hard to grasp about the above, or how it is somehow controversial or worth faffing about that “the scientists can’t make up their minds, first it’s warming now it’s ice age!”.  And that’s being very kind to all the idiotism that is being spewed around the net on the matter. I don’t have time or interest to link to all that.

Frankly, it makes me doubt some people’s mental abilities, if they are unable to understand such simple ideas despite having been taught them numerous times.

Ask in comments if it has not been absolutely clear.

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10 Responses to Anthropogenic Global Warming and Ice Age

  1. mekhami says:

    I have been operating under the pretense that global warming leads to Ice Age… the melting of the polar ice caps leads to a cooling of the ocean currents and inevitably cooling the ecology…

    Is this not a cause and effect?

  2. mike shupp says:

    mekhami —

    A number of factors affect climate; melting of the caps is on of them. Replenishment of the ice on the caps (by snow fall, or freezing rain) is another. The amount of moisture in the air world wide is a factor. The earth’s inclination toward the sun at diferent times of the year is a factor. Whether the earth’s land surface is squeezed together in giant supercontinents (Laurasia, Gonwonaland) or split up as it is at present and precisely where those continents are located are factors. The size of existing ice caps is a factor. The composition of the atmosphere is a factor.

    Nice simple, easily visible cause-and-effect chains are difficult to establish; extraopolating simple patterns over centuries or hundreds of millenia or hundreds of millions of years is even more difficult. Which is why climatologists use computer models and spend lots of time trying to refine those models and arguing about the significance of those models.

    So part of the reason people have problems understanding global warming is that the subject actually is hard; part of the problem is that the processes being studied occur over periods which are quite long compared to a human life, so intuition and “common sense” aren’t necessary applicable.

    And part of the problem people have with global warming is that the fear that if it is determined to be human-caused, then other people (e.g., governments) may take the view that humans should act in ways that alliieviate the effects of global warming, and this will affect their own lifestyles in unpleasant ways, for uncertain gains. It’s not much of a surprise that conservatives and libertarians are the least likely folk to accept global warming; they’re the ones most likely to defend their freedom from any sort of governmental or social intrusion; expecting them do otherwise is like expecting an atheist to suddenly accept a personal savior and fall to his knees in a prayer meeting.


  3. gravityloss says:

    Melting of ice caps can effect the sea currents and have mostly an effect in *local* temperatures for example in Europe (currently warmed by the Gulf stream), which *might* get colder. But at the moment that is still not very thoroughly supported. It might also be temporary.

    If the ice caps melt, the sea actually absorbs a lot more sunlight than the white ice and snow, and hence that will accelerate warming.

    Of course, the billions that live on the coasts are in trouble long before that, the sea level rise by then could be tens of meters.

    But these are things that won’t happen in this century anyway. (Total greenland or south polar ice cap melt etc.) Parts might melt, or are actually already melting.


    The Milankovitch theory of ice ages is quite simple. The orbit of earth is slightly elliptical, meaning that during a year at times it’s closer to the sun and at times it’s farther.

    The attitude of earth also wobbles slowly.

    If you have big continents on the north side of the globe, which reflect light more than the ocean (a bigger fraction of the energy is lost directly), and the wobble and ellipse happen to be so that in the northern summer the earth is closer to the sun, thus a bigger part of the total energy during the year is lost and there is less energy, leading to an ice age.

    What Arrhenius came up with more than a hundred years ago was the role of CO2. First of all it is a greenhouse gas, meaning more of it in the atmosphere makes the earth warmer.
    He understood how it amplified these orbital forcings. Since cold water absorbs more CO2, when it starts getting colder because of the ellipse and the wobble, the seawater starts absorbing more CO2, and it gets even colder because of that. Of course there is a delay since it takes a long time for the oceans to absorb CO2. The same when an ice age ends. The ocean is warmed slightly by orbital forcings only, but it starts slowly releaseing more CO2, which heats the globe more and more releasing more CO2. The CO2 thus amplifies the orbital forcing in paleoclimate.

    Another myth about paleoclimate is that since the CO2 rose after it started getting warmer, it can’t be the cause. But if you read my explanation above, it is obvious that CO2 must follow orbital forcings (come after them) yet it amplifies their effects a lot. It is usually said that in paleoclimate, CO2 is a feedback, not a pure forcing.

    Now, what humans have done is emict CO2 directly by digging up fossil fuels and burning them, and the CO2 put to the atmosphere is thus heating the earth. The CO2 has not been emitted from the oceans, as someone might think. This can be seen firstly by calculating fossil fuel use. You can easily get coal and oil usage statistics and compare them to the mass of the atmosphere and the CO2 portion rise. And then as well be seen from isotope ratios: fossil fuels have certain isotopes of carbon and it can be seen that the atmospheric carbon dioxide in the air has a significant portion of those. (You have to take into account mixing and ocean absorbtion and all that.) This is all very well established stuff and would be foolish to argue against, yet many do so.

    Mike, I have issues with your last paragraph, regarding conservatives and libertarians. Anthropogenic global warming happening or not is an issue of science.

    Even if there are some possible political outcomes that would be unpleasant to them if it is acknowledged, in a rational mind it should not affect the judgement about the science. Our political beliefs can not change the laws of physics. Science is information about the physical world. It can inform policy. But policy can not change science. It does not work that way. You cannot only discover politically pleasant facts about nature in science.

    Hence the issue is very different from your atheist vs religious person analogy.

    On the contrary, conservatives and libertarians should look at what to do if it is true, not stay in outright denial of it happening.

    If a person was a real literal conservative in the original meaning of the word, he would be careful about changes and would value steady states and traditions, hence he would campaign against injecting billions of tons of carbon dioxide to the atmosphere as an uncontrolled experiment even if knowledge was not one hundred percent sure on what happened when that was done.

  4. Dan Skill says:

    In the 1970s, the news media was echoing the siren call of the leading scientists of the time that the Earth was entering a new Ice Age. Data indicated global average temperatures had been falling for 3 decades. The ice caps were growing and animal migration patterns were changing. We were entering a period when food production would decline dramatically leading to starvation on a mass scale.

    What happened to that science? When did the ‘science’ change, and why?

    Was the science wrong then, or is it wrong now?

    Both can’t be correct.

  5. gravityloss says:

    Dan, where do you happen to get your talking points? They are incorrect.
    Cooling was represented in the media but was *not* represented in the scientific literature at the time.

    If you know otherwise, contact William here, he’s actually collecting papers from that era:

    The discovery of CO2 global warming dates to around the 1800s (if not earlier) but the things started coming closer into coherence really in the fifties to seventies timescale.
    Again, if honestly interested, one can read this historical book for free:

  6. Dan Skill says:

    My “talking points” source was the media, as I disclosed in my post.

    I don’t know whether the scientists of the 1970’s are any more or less accurate than scientists today. That’s why I asked the questions.

    Here are some quotes circa mid 1970’s. These are easily Googled if you’re interested.

    “When Climatologist George J. Kukla of Columbia University’s Lamont-Doherty Geological Observatory and his wife Helena analyzed satellite weather data for the Northern Hemisphere, they found that the area of the ice and snow cover had suddenly increased by 12% in 1971 and the increase has persisted ever since. Areas of Baffin Island in the Canadian Arctic, for example, were once totally free of any snow in summer; now they are covered year round.”

    “The University of Wisconsin’s Reid A. Bryson and other climatologists suggest that dust and other particles released into the atmosphere as a result of farming and fuel burning may be blocking more and more sunlight from reaching and heating the surface of the earth.”

    “A survey completed last year by Dr. Murray Mitchell of the National Oceanic and Atmospheric Administration reveals a drop of half a degree in average ground temperatures in the Northern Hemisphere between 1945 and 1968”

    “University of Toronto Climatologist Kenneth Hare, a former president of the Royal Meteorological Society, believes that the continuing drought and the recent failure of the Russian harvest gave the world a grim premonition of what might happen. Warns Hare: “I don’t believe that the world’s present population is sustainable if there are more than three years like 1972 in a row.”

    Donald Oilman, chief of the National Weather Service’s long-range-prediction group is also quoted.

    Are these not respectable sources for data and science?

    I’ll ask again; What happened to the science? When did the ’science’ change, and why?

    Was the science wrong then, or is it wrong now?

    Both can’t be correct.

  7. gravityloss says:

    Heh, you can pick some things from the media from back then, sure. Yet even those don’t seem to predict cooling on a 100 year time scale. They’re just observing some effects. All three of your examples. How do they conflict with CO2 global warming? Not at all.

    And they’re not a comprehensive view of the science by any means anyway.

    Again, just look at Connolley’s survey of papers. There may have been some scientists that perhaps thought cooling was the major problem (which is not indicated by your quotes by the way), but it doesn’t seem anywhere close to how much science has been done for global warming nowadays, with so many multiple lines of evidence, statements from science guided bodies, the whole IPCC thingy etc etc.

    Take for example Stephen Schneider. Much noise has been made by certain people about how he turned from predicting an ice age to predicting global warming. Here are some excerpts from his book from the early seventies:

    “One form of such pollution that affects the entire atmosphere is the release of carbon dioxide (CO2) gas…. Human activities have already raised the CO2 content in the atmosphere by 10 percent and are estimated to raise it some 25 percent by the year 2000. In later chapters, I will show how this increase could lead to a 1o Celsius (1.8o Fahrenheit) average warming of the earth’s surface… Another form of atmospheric pollution results from… atmospheric aerosols… there is some evidence that atmospheric aerosols may have already affected the climate. A consensus among scientists today would hold that a global increase in atmospheric aerosols would probably result in a cooling of the climate; however, a smaller but growing fraction of the current evidence suggests that it may have a warming effect”

    Your “question” doesn’t make any sense.

  8. Dan Skill says:

    Aw, c’mon now. Obviously, I’m not a high falutin’ scientist like you are. Just a citizen looking for some answers. And, you’re getting pretty close to providing them . . . I think.

    It appears that a reporter or two got wind of the “Earth is Cooling” study and decided to start asking some questions. Their sources, climatologists and scientists all, offered their opinions, and the reporters jumped to conclusions and ran with the story.

    The Time and Newsweek stories both echoed the same sources. Much ado about nothing. That’s easily understood.

    So, thanks for the guidance.

    At the risk of eliciting your biting commentary about my questions, I’ll pull on my big boy pant and ask them anyway… for the layman, how do we know what ‘normal’ is for the world’s climate? In short, what/where is the proof that man has/is pushing the earth to change climatic conditions?

  9. gravityloss says:

    Thanks, Dan.
    For defining normal, I’d research the keyword Holocene: the last roughly 10,000 years of relative climatic stability, during which the human civilization has developed.
    Before that there was an ice age.

    There are multiple lines of evidence for the CO2 warming. Lab experiments and basic physics, lack of changes in solar output that can be monitored with satellites, signatures in heating patterns etc… A physically correct climate model can’t reproduce the climate without also reproducing global warming. It’s not a “tuning until you get global warming”, rather the opposite. If your model is reasonably accurate / correct otherwise, global warming just turns out naturally.

    And even in the past climates, the ice ages, CO2 has played a role. Then it was not the prime source for warming or cooling but it amplified warming since more CO2 was released from warmer water. A positive feedback. The rapid state changes between ice ages and warm times were a hard thing to explain with just Earth orbital parameters since the changes in forcings would be so small. But when CO2 information and knowledge of its greenhouse behaviour was taken into account, things started making a lot more sense. AFAIK Recent better data has improved this. It’s even available on the net:

    This one shows the Holocene:

    And this shows the ice ages (Holocene being the warm blip at the right):

  10. gravityloss says:

    Also, I’m not a scientist…

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