I would like a concise explanation for why interglacial cycles end and why global warming is logarithmic (power, advance)
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Anybody know any concise hypothesis for why interglacial cycles might end? It doesn't have to be right. It just has to potentially explain it in clear, concise English without any damn graphs or links to studies. All I've found so far basically amounts to...it has to do with Milankovitch cycles, or it's not quite understood. I know during interglacial cycles there are high rises of C02 which closely mirror the rise in temperature. What I don't understand is why that comes down again. About the only potential explanation I can think of is that the additional C02 increases plant growth, which absorbs up more C02, which, combined with the effects of Milankovitch cycles, the Earth is able to experience a drop in C02 and cool again. Might that be decent explanation, or is there a better one? Or is it just that the affect of Milankovitch cycles on the Earth might almost totally overwhelm most other factors and just be able to bring down Earth's temperature by itself?
Anybody know why global warming is considered logarithmic? What I mean by that is, the more C02 enters the atmosphere, the less each additional molecule of C02 will warm the atmosphere...not counting feedback loops stemming from additional C02 that might continue to magnify Earth's temperature. Again, I'm not necessarily looking for accuracy. I'd prefer it to not be perfectly accurate, so it'll be more concise. I just would like some kind of general explanation for why, even without feedback loops, one more molecule of C02 wouldn't increase Earth's temperature the same amount whether the atmosphere is filled with C02, or nearly empty of it.
There could very well be a pretty simple, commonsense explanation I'm just not thinking of. I find that oftentimes the difference between the people who really understand seemingly complex topics and the people who don't has a lot to do with not catching those fairly simple, commonsense ways of looking at things though.
Thanks. I love this forum, by the way. You people are awesome.
One of the key posits of M cycle theory is that the land heats more than water. One of the effects of global heating is the melting of ice, leading to rising oceans, which equates to a larger water surface and smaller land surface. Therefore, temperatures can drop. Take a look at some of the dire consequence maps showing "if all the ice melted" for an example. However...
Humans have a tendency to find a simple model for how something works and then depend on it to the point of it becoming a fetish. We are designed to do that by early evolutionary pressures. With complex systems having multiple feedback loops, Occam's Razor fails miserably, and full understanding is thwarted by early jumping to conclusions. I urge you not to fall into the trap of the CO2 fetishists and others with pet theories, who have found two pieces of a jigsaw puzzle that fit together and declare that they have solved the puzzle.
Just off the top of my head, I could list a dozen or more factors that affect climate and the average global temperature, and events that could disrupt both. Be very distrustful when someone suggests a single key factor as the "answer" to climate change. If you want to mess with their minds or watch some serious psychological coping strategies, point out additional factors that they haven't considered, and sit back and watch.
One of the key posits of M cycle theory is that the land heats more than water. One of the effects of global heating is the melting of ice, leading to rising oceans, which equates to a larger water surface and smaller land surface. Therefore, temperatures can drop. Take a look at some of the dire consequence maps showing "if all the ice melted" for an example. However...
Humans have a tendency to find a simple model for how something works and then depend on it to the point of it becoming a fetish. We are designed to do that by early evolutionary pressures. With complex systems having multiple feedback loops, Occam's Razor fails miserably, and full understanding is thwarted by early jumping to conclusions. I urge you not to fall into the trap of the CO2 fetishists and others with pet theories, who have found two pieces of a jigsaw puzzle that fit together and declare that they have solved the puzzle.
Just off the top of my head, I could list a dozen or more factors that affect climate and the average global temperature, and events that could disrupt both. Be very distrustful when someone suggests a single key factor as the "answer" to climate change. If you want to mess with their minds or watch some serious psychological coping strategies, point out additional factors that they haven't considered, and sit back and watch.
I agree with the above...although I'll note that I think simplifying concepts as much as possible is an important step towards understanding them.
So...you showed me another factor that could help cause an interglacial period to end. That's an example of the sort of information I was wanting. Thanks.
I'm still wondering about why climate change is logarithmic though. Skepticalscience.com is no value to me when it comes to understanding that. It just gives the following information, and I can't find more useful information elsewhere either. It's all just graphs and numbers:
An answer, or hypothesis I might me looking for is something like, maybe: "The reason why the more C02 you put into the atmosphere, the less each individual molecule of C02 increases temperature is that the more molecules of C02 are in the atmosphere, the less likely each individual molecule is to catch heat and reflect it back to Earth's surface, because most of the heat will be reflected by other C02 molecules instead" or something like that.
I can't find something like that anywhere. Einstein had a great way of describing complex issues in simple ways. That's what I'm looking for here.
Here was the original statement I saw that peaked my interest. it's from the above webpage I listed. I want to know why, in the words on the webpage "each subsequent stage of reinforcement & increase will be weaker and weaker".
Some skeptics ask, "If global warming has a positive feedback effect, then why don't we have runaway warming? The Earth has had high CO2 levels before: Why didn't it turn into an oven at that time?"
Positive feedback happens when the response to some change amplifies that change. For example: The Earth heats up, and some of the sea ice near the poles melts. Now bare water is exposed to the sun's rays, and absorbs more light than did the previous ice cover; so the planet heats up a little more.
Another mechanism for positive feedback: Atmospheric CO2 increases (due to burning of fossil fuels), so the enhanced greenhouse effect heats up the planet. The heating "bakes out" CO2 from the oceans and arctic tundras, so more CO2 is released. In both of these cases, the "effect" reinforces the "cause", which will increase the "effect", which will reinforce the "cause"... So won't this spin out of control? The answer is, No, it will not, because each subsequent stage of reinforcement & increase will be weaker and weaker. The feedback cycles will go on and on, but there will be a diminishing of returns, so that after just a few cycles, it won't matter anymore.
The plot below shows how the temperature increases, when started off by an initial dollop of CO2, followed by many cycles of feedback. We've plotted this with three values of the strength of the feedback, and you can see that in each case, the temperature levels off after several rounds.
Anybody know why global warming is considered logarithmic? What I mean by that is, the more C02 enters the atmosphere, the less each additional molecule of C02 will warm the atmosphere...not counting feedback loops stemming from additional C02 that might continue to magnify Earth's temperature. Again, I'm not necessarily looking for accuracy. I'd prefer it to not be perfectly accurate, so it'll be more concise. I just would like some kind of general explanation for why, even without feedback loops, one more molecule of C02 wouldn't increase Earth's temperature the same amount whether the atmosphere is filled with C02, or nearly empty of it.
Imagine you're driving through a snow storm with your car headlights turned on. Now think of a single ray of light coming from the headlights. As the amount of snow in the air increases, two or more snow flakes are more likely to line up along the same ray. If the first snow flake blocks the ray, the second is ineffective. Once the snow is heavy enough, you reach a point of diminishing returns.
I agree with the above...although I'll note that I think simplifying concepts as much as possible is an important step towards understanding them.
So...you showed me another factor that could help cause an interglacial period to end. That's an example of the sort of information I was wanting. Thanks.
I'm still wondering about why climate change is logarithmic though. Skepticalscience.com is no value to me when it comes to understanding that. It just gives the following information, and I can't find more useful information elsewhere either. It's all just graphs and numbers:
An answer, or hypothesis I might me looking for is something like, maybe: "The reason why the more C02 you put into the atmosphere, the less each individual molecule of C02 increases temperature is that the more molecules of C02 are in the atmosphere, the less likely each individual molecule is to catch heat and reflect it back to Earth's surface, because most of the heat will be reflected by other C02 molecules instead" or something like that.
I can't find something like that anywhere. Einstein had a great way of describing complex issues in simple ways. That's what I'm looking for here.
Here was the original statement I saw that peaked my interest. it's from the above webpage I listed. I want to know why, in the words on the webpage "each subsequent stage of reinforcement & increase will be weaker and weaker".
Some skeptics ask, "If global warming has a positive feedback effect, then why don't we have runaway warming? The Earth has had high CO2 levels before: Why didn't it turn into an oven at that time?"
Positive feedback happens when the response to some change amplifies that change. For example: The Earth heats up, and some of the sea ice near the poles melts. Now bare water is exposed to the sun's rays, and absorbs more light than did the previous ice cover; so the planet heats up a little more.
Another mechanism for positive feedback: Atmospheric CO2 increases (due to burning of fossil fuels), so the enhanced greenhouse effect heats up the planet. The heating "bakes out" CO2 from the oceans and arctic tundras, so more CO2 is released. In both of these cases, the "effect" reinforces the "cause", which will increase the "effect", which will reinforce the "cause"... So won't this spin out of control? The answer is, No, it will not, because each subsequent stage of reinforcement & increase will be weaker and weaker. The feedback cycles will go on and on, but there will be a diminishing of returns, so that after just a few cycles, it won't matter anymore.
The plot below shows how the temperature increases, when started off by an initial dollop of CO2, followed by many cycles of feedback. We've plotted this with three values of the strength of the feedback, and you can see that in each case, the temperature levels off after several rounds.
The graph and math are a conflation of atmosphere CO2 percentage AND black body radiation rates. The hotter a black body gets, the more energy (heat) gets radiated. The model itself is very limited and doesn't take into account other effects. From the "advanced" tab explanation:
" There is in fact a negative feedback that always tends to win out, which is the increase in planetary radiation with temperature. Positive longwave radiation feedbacks only weaken the efficiency at which that restoring effect operates. Instead of the OLR depending on T4, it might depend on T3.9, or maybe even T3 at higher temperatures; eventually the OLR becomes independent of the surface temperature altogether. "
After digging through the page and comments, the sum total of my response to the model is "You've shown that black body radiation is more powerful an energy shifter than a static chemical compound. We knew that."
To take that limited model and attempt to apply the "self-limiting" conclusion to a broader base, like climate change as a whole, is a stretch too far.
Many natural phenomena follow something closer to a logarithmic curve than a linear one. I don't think it should be hard to grasp why, for example, a warming trend that is not dampened by other factors becomes a logarithmic or exponential change; when the balance is disturbed, warming promotes warming, cooling promotes cooling, and those trends (hot eras and ice ages) tend to persist until something comes along and again disturbs the balance.
Look at populations - a declining population tends to decline; an increasing one tends to increase, and the curves are often far from linear.
Thanks folks! If I ever get any psychic powers, I will try to telepathically give you all random spikes of euphoria. If any of you are driving or operating heavy machinery when this occurs and lose important appendages, or are killed as a result I'll owe you my most sincere apologies.
Anybody know any concise hypothesis for why interglacial cycles might end?
Aren't you putting the chicken before the egg? Your view's a bit ethnocentric.
A better question is, "Why do Glacial Periods end?"
This is normal Earth:
That's what Earth is like 80% of time.
The cause of the current Ice Age is pretty clear. The Strait between North America and South America closed with tectonic action creating the Panamanian Isthmus.
At roughly the same time, the Antarctic Continent began sliding into the Antarctic Region.
This Ice Age will last until a substantial part of Antarctica moves out of the South Polar Region. I thought its movement rate was 1.5-2.0 cm per year, not that it matters, since it's not going to happen in our life-times, and humans may not even be around by the time it does.
The scientific evidence shows Glacial Periods lasted 40,000-42,000 years and Inter-Glacials 12,000-15,000 years until the Mid-Pleistocene Event 600,000 years ago which resulted in Glacial Periods lasting 80,000-120,000 years and Inter-Glacials 12,000-30,000 years.
This Inter-Glacial could end tomorrow, or 18,000 years from now.
The fact that Inter-Glacials do end is problematic for the global warming hypothesis.
If the global warming hypothesis had validity, then Inter-Glacials should never end. Earth should continually warm, but that's not what the evidence shows.
Some disingenuously attempt to link Glacial/Inter-Glacial Periods to Milankovitch Cycles, but those fail, too.
The Precession of the Equinoxes which is roughly 25,500 years has a bearing on astronomy and astrology, but not climate.
The 41,000-year axial tilt cycle "appears" to be a causal factor, because pre-Mid-Pleistocene Glacial Periods lasted 40,000-42,000 years, but that's only apparent. When you examine the data, it fails.
If the axial tilt is responsible for Glacial-Periods of 40,000-42,000 years then why aren't Inter-Glacials also 40,000-42,000 years?
Then line up the data, back-to-back Glacials/Inter-Glacials.
You can't claim Earth at its greatest obliquity -- ~21.0° -- causes Glacial Periods, because it doesn't and Earth closest to the vertical -- ~24.5°-- doesn't cause Inter-Glacials. The axial tilt makes no difference, although it might cause minor temperature changes up to 1.0°F.
The 100,000-cycle doesn't play a role, either. 40,000-42,000 years is not 100,000 years any more than 80,000 years to 120,000 years is 100,000 years. If it was 95,000-105,000 years maybe they'd have a point, but that only begs the question "Why now?" and not prior to the Mid-Pleistocene Event.
There's a lot of evidence suggesting that this Inter-Glacial Period began unnaturally, through a cataclysmic event.
That's not to say that we wouldn't be in an Inter-Glacial Period, because we would be, it's just that it would have started 3,000-5,000 years ago instead of 12,000 years ago.
If you look at the map, an Inter-Glacial is very obviously preferable over a Glacial Period.
That map belies the fact that the only arable land is in the equatorial band, between the Tropic of Capricorn and the Tropic of Cancer.
That's not enough to feed 6.5 Billion people.
But none of that matters, because you'll have problems long before anyone ever sees the first glacier.
Look back at the mini-Ice Age and you can see that.
The people in the 100+ New England Colonies were near starvation. They survived only because of imports and the southern Colonies.
The growing season was only 6 weeks. The had from the first week of July to mid-August to prep the field, plant seed, let the crops grow and harvest what they could before the first frost killed everything. In the area that is now between I-80 and I-70 the growing season was only 10 weeks.
In Central Europe, Millions died of starvation. They couldn't grow crops, and the neighboring kingdoms and duchies it was all they could do to feed their own people, so there was nothing to export.
And, you say, "Well, we have tractors and modern farming equipment."
So?
When farmers do a soil test, they take a rod of standard rebar about 1/2" in diameter and hit it once with a 5-lb sledgehammer.
If the rebar goes at least 2" in the soil, they can till, and if it doesn't, they cannot.
If the soil is frozen, it's frozen, and modern tractors with stainless steel plows makes no difference.
If the global warming hypothesis had validity, then Inter-Glacials should never end. Earth should continually warm, but that's not what the evidence shows.
Some disingenuously attempt to link Glacial/Inter-Glacial Periods to Milankovitch Cycles, but those fail, too.
Do you have some reference that backs up what you claim here? I have some references that dont agree with you but am wondering if you came to this conclusion on your own or is there a valid reference that also agrees.
Good subject by the way and it will be more interesting if everyone gives references - ie, fact check yourself. Or if its something you figured out yourself.. let us know.
The last 800 thousand years is the most interesting to us now because the continents and oceans, mountains etc are going to be somewhat the same as they are now and we have CO2 vs temperature data from this time period.
The OP mentioned feedback mechanisms. A key thing to understand and which seems to be missed is that CO2 can be BOTH feedback and driver mechanisms for temperature change.
CO2 is a feedback mechanism because as temperature rise, the ocean temperature also rises releasing CO2 into the atmosphere. Since CO2 is a greenhouse gas, this is positive feedback because the initial temperature rise caused more greenhouse gas which in turn causes more temperature rise. For CO2 as feedback, the concentration of CO2 will have a time delay compared to the driving temperature change. Ie, CO2 concentration will lag temperature change.
CO2 can also be a driver. If you simply add CO2 to the atmosphere so that its concentration increases, it will cause temperature to rise because it is a greenhouse and traps energy. When CO2 is a driver, the concentration of CO2 will precede the rise in temperature. Ie, CO2 concentrations leads temperature rise.
Before we came along, CO2 mainly acted as a feedback mechanism and reacted to and amplified temperature change.
Now we have the natural CO2 feedback mechanism happening that has gone on for 800K years but we are also now adding CO2 to the atmosphere and that is a driver mechanism. CO2 is now acting as both a driver and feedback.
Best when you fact check yourself.. so here is a link below
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