What causes ice ages?

Do you buy that Antarctica moving over the south pole was a mover in the current ice age, f-man?

Answer - the ice at the poles gets into a runaway expansion.

Q. What causes that?

A. Gradual lowering of the average temperature year on year for too many years causes ice build up that doesn't thaw more than it grows each winter, so therefore the ice starts to seasonally expand over new terrority each year until it reaches runaway propotrions.

Q. What causes that?

A. Less energy falling on the Earth's surface and less heat being retained by the Earths oceans.

Q. What causes that?

A. The atomshpere reflects more energy than it traditionally lets through for a sustained period of time, and the ice itself reflects the heat in sunlight back into the air - which has poor heat capiticance.

Q. What causes that?

A. A variance in the proportions of gases (particularily any lowering of CO2) in the Earth's atomsphere reduces heat retention plus the amount of fine pollutants (especially volcanic dust) that float for a long time and reflect sunlight at high altitudes away from the land but more importantly away from the Earth's oceans, causing a dramatic loss in heat retention, and lastly cloud cover increasing trapping more heat in the clouds (which quickly radiates heat at night) rather than in the oceans which leak heat much slower in the night time.

Q. What causes that?

The CO2 levels - plants (photosynthesis) and algae (the more important contributer, producing most of the Earth's oxygen - going into overdrive) - producing lower net levels of CO2 to retain greenhouse heat.

Fine dust - unusually high levels of volcanic activity (due to changes in plate tectonics) and to a far rarer extent large meteorite impacts throwing massive dust clouds into the air.

Cloud cover - above average moisture in the air (at lower altitudes), normally the fine dust would seed the clouds to rain more - unless it is at very high altitudes, above moisture laden winds.

Q. What causes that?

A. Sigh - how far do you wish to go?

It appears cyclic - maybe larger meteorites, maybe an overabundance of forest fires caused by lightning strikes, maybe unusual plate tectonics on a periodic resonance, maybe changes in the acidicity and pH levels of the oceans caused by changes in the atomsphere, or bowels of the ocean.

//Good question though!

Wouldn't it be ironic if future historians looked back (probably from the top of their glaciers) at our fossil fuel era, as humanity's first attempt at climate control, rather than simple neglect over the waste from our industrial activities.

I agree. There are large scale trends as well as small scale trends (small for us being hundreds of thousands of years).

Al Gore and the Nobel Prize

Mr. Gore seems convinced that human CO2 emissions are causing climate change (or at least accelerating it). I'm convinced that the climate is changing, but I'm not convinced that human activity is the main cause of the change (or even a minor contributor). The ice core history shows dramatic climate change long before humans were involved, so what makes these eminent scientists/statesmen think that the causes are different now?

In all honesty, am I missing something? Is there some evidence that not only is the climate changing, but that human CO2 emissions are the primary cause?

I know that human activity is increasing CO2 in the atmosphere, but I also know that if you throw a bucket of water into Niagara Falls you are increasing the flow. But the real question is "How much" are you changing things in the scope of things. Is our CO2 activity really changing things that much, or is it just a bucket in the waterfall?

Thanks,

You may want to look into this as NOT caused by physical phenomena but rather by the inherent instability of a non-linear system. If you really want to to get your feet wet I could suggests the paper "Period Three Implies Chaos". It appears that this could be a natural consequence of the system itself and all phenomenological attempts to explain it, while understandable, none the less inconsequential.

That sounds like you're agreeing with my current analysis, which is that climate change is not dramatically affected by human CO2 emissions (see details contained in this thread).

What I'm curious about now is why Gore (who seems to be a smart guy with sincere motives) seems so convinced that humans ARE affecting climate change to a dramatic level? What evidence (or reports) is he looking at that I'm not aware of? Does anyone know? Has it been reported, and I just missed it?

No I'm not agreeing with that conclusion. I'd be happy to discuss how non-linear dynamics makes ANY change far more frightening since the effect of the change, being non-linear, can be tremendously larger than the perturbation. Unfortunately, correctly or incorrectly, I see adding Al Gore to the mix as taking us from the realm of objective science into politics or problems with a specific individual which, in my opinion, makes emotionless science discussions problematic.

A non-linear system can certainly be affected by perturbations from outside influences; it is predicting their effects that can become much more difficult. For your argument this unfortunately means it is just as likely that the addition of CO2 is far MORE damaging to a steady state climate than being inconsequential. It goes both ways. Because one straw does not break the camel's back doesn't lead to the conclusion that the camel can hold any amount of straw without catastrophic consequences.

Perhaps the direction of this question means it is better placed on the politics group.

On the other hand, your conclusion will, I'm sure, put you in complete agreement with RL, BD, gunga, spendius, etc. I'm not sure if you will feel that as good or bad but I'm sure it will feel different.

i wonder if RL can agree with your conclusions while still insisting that the conclusion violates the second law of thermodynamics?

For a number of reasons, Im not on the "anthropogenic causes of climate change" train.
However, having said that, both models for the human induced AND the malenkovitch /drift theories have crashed miserably.
Dick Alley at Penn State is taking a carefully paced approach.

The entire carbon cycle is not fully understood and the values for hguman contributions vary from 0.025% up to "All of it" .
Many times we introduce what we call "best management practices" to help alleviate problems only to find out that what was apparently direct evidence is not so correct. There was a law in hydrology that stated that , as we approach 10% impervious surface in rainfall recharge, we seriously affect water supplies and sustainability of ground water. That was a Biblical truth for decades. Not so much credibility is given it any more.

Im no fan of GW Bush, but the global warming train has been so politicized that its difficult being a liberal and then being castigated by other liberals for not drinking the Global warming Kool AId.


Geology gives one an interesting perspective. Dick Alley is a glacial geomorphologist originally. Recent work by Holbrook et al concerning diffusivity of thermoclines gives another insight into the relationship of malenkovitch minimums and polar ice.

What causes ice ages?

Insufficient cow farts.

I'm curious TCR, have you actually read this thread? After what you know about me from my posts on other threads, do you really think I'm going to do like RL and start quoting the bible to support my conclusions?

I'm not interested in a political discussion of Al Gore. And I'm not interested in Democrats or Republicans or Liberals or Conservatives. I'm interested in separating the actual science from all the emotion and politics.

It's pretty clear from the evidence presented throughout this thread that climate cycles occur without human intervention, and that if humans were not here at all, the temperature would still be spiking just like it has before. The ice core record leaves this pretty much undebatable, it doesn't matter what kind of non-linear dynamics you want to throw at it.

The question remaining is whether or not the addition of human activity is having any meaningful impact on the patterns which have already been established by nature. This is what I'm asking for. What evidence exists, or has been presented, which tries to evaluate the relative impact of human CO2 emissions on natural patterns?

One issue you've not addressed is local conditions. The north Atlantic region experienced a local cooling in the period (roughly) 500 BCE to 500 CE. That had a very large impact on the pelagic species upon which certain European cultures and certain North American cultures relied--chiefly whales and seals. The archaeological record and (in Europe) the historical record show such cultures moving south, very likely in response to the migration of the pelagic species. This was followed by a warming spell, when temperatures rose far enough that after a few centuries (by the 9th century of the current era) the Norse began making permanent settlements on Iceland. Previously, the Picts and the Irish had used it as a summer camp for hunting pelagic species. Thereafter, the warming period continued until about 1200 CE, after which the climate rapidly got colder, and the effect of the new mini-ice-age was far more widespread than the previous one, and reached much further south. By the early 17th century, lakes in northern Scotland were frozen over by the end of August. By the early 18th century, nations in western Europe were recording the most severe winters in their recorded histories. The winter of 1709 was so severe that rabbits froze to death in their burrows, birds froze to death and fell from the trees, and the guards on the barriers at Paris had to be increased because wolves were entering the city and attacking children and elderly people in the streets. Throughout the period (roughly) 1600-1800, the Thames River froze over, until by the end of that period, it was generally assumed that this would occur every winter.

However, there is no evidence that a similarly severe cooling period occurred in the northern Pacific in either the period 500 BCE--500 CE, or 1200 CE--1750 CE. I'd be interested to know if anyone today is comparing say, the Antarctic seas and Southern Ocean data with previous years, and if global warming is in evidence in those regions as it appears to be elsewhere.

There are lots of variations on the short term. Last year it was very warm here (New England) through January. This year it's colder than normal in December. This doesn't change the very cyclic nature of the evidence from the ice cores which shows a very distinct pattern.

I guess I'm not sure what your point is regarding short term fluctuations. Are you suggesting that we can't trust long term patterns because we can't explain short term variations?

ROS:
Yes I do know that about you which is why I can't understand adding all Gore to the mix? As you know MANY reputable scientists with no apparent axe to grind are apparently very concerned with the data they are looking at. Why should I disregard these experts any more on this post than any other. Wouldn't it be your job to disprove them? Just saying that there have been non-human induced fluctuations is, to me anyway, not much of a refutation.

Truth in advertising forces me to admit every time I have looked with interest on the subject I have always been sidetracked by interesting chemistry of the atmosphere or, even more, the oceans, and my reading went on a tangent to these things which interest me more. Since I have no kids and don't plan on any I have no one to which I have to explain the way I left the word when I go. So eat drink and be merry!

When it is not directly in my field and a cursory look at the data seems to support expert opinion I go with the experts. Since this is a big topic I will simplify it enormously to make my point.

Only in the minds of theorists and in text books do we have the luxury of an infinite amount of noiseless data. In the real world we have limited, sometimes depressingly limited, amounts of noisy data. The question always is when the data is good enough to draw a conclusion. Saying that, I'll take one example of data from the always happens, always will school, and one from the man influenced school.

We take as axiomatic that the sun is directly responsible for the Earth's climate. One of the most direct measures of the sun's activity to earth's climate is sunspot number. The lower the level of sunspots on the sun the more likely the earth's climate will be colder than "normal". We are all aware of the Sporer Maximum and Maunder Minimum corresponding to a time of increased global temperature and decreased global temperatures, respectively.

I actually did some research on this years ago (unfunded research) to determine if the sunspot numbers and their variations at that point in time were reasonable compared to the Zurich numbers of the last fifty years, It was impossible not to also get into the climatic implications. When looking at the numbers versus climate change there was certainly a correlation from many disparate source of data but the correlation was quite sloppy especially the at the beginning and ends of the sunspot extremes. The data was noisy but I could tolerate the fudging to help the points to fit the climatic curve, it was, in my opinion, reasonable.

Today, looking at the graph of the amount of CO2 increasing in the atmosphere vs temperature increase (for example), say over the past 100-150 years. The data is SO strongly correlated, in my opinion, than rather than understand someone saying they see nothing there I would think the reaction would be, as mine first was, someone is cooking the books! It is, again in my opinion, a much closer match than anything of that magnitude than I am used to dealing with.

Since this has gotten too long already even with my attempt to strip away so much of the complications I'll try to end it here. If someone looking at the data finds no correlation with man-made contributions to global warming I am at a loss as to how they would find any correlations to solar activity and global climate change. Let alone find correlations with more complicated astronomical dynamics such as the Milankovitch cycles; where even techniques such as fast-fourier analysis leaves a lot of ambiguous, tangled data which necessarily leads to somewhat arbitrary conclusions.

I can agree with FM, after looking into the chemistry I noted above, there is a LOT we don't know. If one wants to take that premise I think we move from a scientific question to one of risk analysis. This was the one of the reasons that I brought up the non-linear dynamics into the mix. If, for example the earth's climate can be modeled on a strange attractor and a large enough perturbation takes place (which could be very tiny in actual scope of change) we won't necessarily increase the orbit speed on that attractor (for instance) we could move to a new attractor entirely. This is almost always a non-reversible change. At that point stopping all "problematic" human activity could not help in the slightest in EVER getting us back to where we were. If the climate modeled by the new attractor is the "white-earth" scenario we are toast and no going back; if it is a climatic Eden, so much the better. The problem is in a non-linear world by the time we find out we've past the point of no return.

Since you have been patient to this point I'll add: from a practical point of view I don't think you have anything to worry about. Except it is a new cause for celebrities to take up and the odd billions of tax dollars for useless research that the Oil companies will get from congress (which they would have gotten for something else anyway) I don't see any real action being taken that will effect your life. Here in America with the gas shortage and then the constantly inflating costs of fuel we couldn't manage to get fleet economy standards raised a lousy 2 mpg in 40 years. Does anyone really think that anything substantive can be agreed on when we now have to include China, India, etc.? Sorry for being so wordy.

No, i'm suggesting that without comprehensive data, we can't be sure what the patterns are, locally, nor what sort of temperature fluctuations we should expect. I suspect that there is insufficient data to be certain of whether or not current alleged warming results from human activity, or is "regionalize" or "localized," or is a part of a pattern which has not yet been identified. So, for example, evidence of rising temperatures in northern arctic regions may or may not be a product of human-generated greenhouse gases, but i suspect it can't be said with certainty without more and more reliable data.

In essence, i'm asking questions. Is the entire global climate warming? Is there evidence that this is a significant departure from what can be expected in the course of "natural" temperature fluctuations?

My reply got locked before I could edit it and add my last point. If you are talking specifically about ice ages I think the best answer is we don't know. Outside phenomena could be the cause but just instability of the system itself can also be the explanation. The point of man possibly affecting the climate is entirely different than what caused the ice ages and our best data, in my opinion, leans to yes he can cause climatic changes.

By the way, i'm not claiming detailed knowledge of climatology here. My questions arise from what i know of the spread to the two main "Eskimo" cultures of the North Atlantic region, the Dorset people and the Thule people, and the archaeological evidence of their spread in what is now eastern Canada and Greenland. The Dorsets were much taller than the Thule people, and were in fact much taller even than the Norse. Both Thule people and the Norse referred to them as "giants." The Norse believed that Norway, Spitzbergen, Greenland and what we would consider eastern arctic Canada were all connected by land. Before Greenland was colonized by the Norse (there is inferential evidence that the Irish and/or Picts were there before the Norse), they referred to the ice packs to the east of Greenland, which they thought covered dry land, as the land of the giants. Some ethnologists have taken this as inferential evidence that Dorset culture people hunted the pack ice east of Greenland.

What is certain, however, based on archaeological evidence is that the Thule culture people arrive on the eastern coast of what is now Canada (Labrador) near the end of the cooling period, when hunting seals would have lead them east to the ocean, and south to the edge of the pack ice.

In some PMs that FM and i exchanged, he told of someone he knows at Woods Hole who is studying salinity, and suggests that perhaps changes in salinity lead to the changes in the range of the pack ice.

For anyone interested a good place to start for information would be here:
http://www.ncdc.noaa.gov/paleo/globalwarming/paleodata.html

NOAA is considered, as far as I know, to be both apolitical and provide top notch data and data analysis. What the site doesn't do for you is to superimpose atmospheric CO2 levels and temperature level charts, for example. You will also get an idea of what I meant by noisy data.

For anyone needing totally unambiguous data of man-made effects it is probably just best to assume there is no correlation whatsoever, that no matter what man does he cannot possibly effect the earth and move on to something else. If you are looking for the normal type of evidence we usually are stuck working with from which to draw a conclusion this is one of the best (non expert targeted) sites available, in my opinion.

I want to thank you guys for your responses, but I seem to be confusing things by asking my latest question in my Ice Age Thread. I'm trying to focus on a different question now, so I'll start a new thread.

The only reason I mentioned Al is because his recent nobel prize is what drew my attention to the question.


That's kind of why I was asking the question. Since I (an amateur with limited time to study such things) find myself disagreeing with Nobel Prize winners, I have to ask myself, "What am I missing"? Which is exactly why I asked my question.


Before I can even try to disprove them, I would like to understand what they are claiming.

It's not clear to me whether they are just saying the earth is warming (which I already know), or whether they are also claiming that human activity is significantly responsible for the warming.

IF they are claiming that human activity is responsible for that warming, then I would like to understand how they determine this. And for the moment, I can't find ANY data which addresses this part of the climate warming issue. The media (and most people) are so focused on the WARMING aspect of the issue that they are not explaining how they determine the contributing factors in the warming.

I've moved beyond warming, and so should everyone else. It's warming, no doubt about it. And we know there are multiple factors contributing to the warming. The question I'm trying to get information on is, "how much does human activity contribute to the warming?". The Nobel scientists seem to know. But I can't find a concise statement of HOW they know this anywhere. HOW do they know this? Where's their data?