The tidal force isn't too much different, relativistically. Dimensionally the tidal force still has to look something like GMm/R^3 deltaR. I looked up the relativistic calculation in Misner, Thorne, and Wheeler (in Section 32.6, with the charming running title "Gore at the singularity). There should be a 1/4 in front of that expression. The horizontal compression in any direction is half that of the vertical tension. I am no expert on what that would do to a star.
No. No amount of pressure can prevent a collapsing universe from collapsing; that's the content of various cosmological singularity theorems. This doesn't even prevent simple things like galaxies colliding. It really only works because a black hole event horizon is relatively small, and it's hard for a lot of matter to all cram in. But in a collapsing universe, once you get to the point that things are starting to collide, the collapse has already built up enough that it's unstoppable. Past a certain point, pressure itself gravitates more than it repels. That's why black hole collapse is inevitable beyond a certain critical mass.
Regarding your thought experiment: the cosmic microwave background radiation is a much larger influx than the Hawking radiation outflux of any stellar (or larger) black hole. So unless the black hole is isolated from the rest of the universe, it will always grow from cosmic radiation, even if no matter falls in. (Or at least until the universe expands enough that the background radiation becomes cooler than Hawking radiation; see here, in the second half.)
Well, I'll admit this sounds intuitive with the Penrose-Hawking singularity theorems applied to the Big Bang.
No, it has nothing to do with singularities (or the Big Bang). It has more to do with matter which orbits black holes.
Now, I'm not a physicist either but I have read a lot that speculates the Big Bang was a singularity that created a hot unstable mess. All the mass of the universe in a singularity suddenly starts blowing out and producing massive heat. Although what was around this singularity is nothing--not even space.
Don't think of the singularity as a point that blew matter in all directions. As you correctly note, there is nothing "around" a singularity. For now limit consideration to an infinite universe, which is preferred by standard inflation scnearios. Then a singularity isn't even really a single point. The universe is still infinite in extent, it's just that the matter/energy in it is of infinite density. (See here.) Think of the Big Bang as where space expands making the matter less dense, rather than some single location that spews matter away from itself.
As always, it brings up interesting questions about what was before that epoch since it is kind of clear that such a singularity could not be possibly be stable for any amount of time (as this research indicates).
To reiterate, this research has nothing to do with the singularity inside of black holes. It has to do with matter which is outside black holes not being able to make its way in, due to the pressure created by other infalling matter. The black hole itself does not emit any appreciable matter/radiation (other than a very tiny amount of Hawking radiation).
All I could think of was that I really wish they called micro black holes that exist for minute fractions of a second something other than "black holes." It scares people unnaturally.
I agree. "Micro black hole" is a terrible name. I prefer "Death, Tiny Destroyer of Worlds".
Strictly and classically speaking, that's correct. However, since the string is always vibrating, you're going to see more or less its full extent in our 3D space as different parts of it pass through our 3D hyperplane at nearby instants of time. If you could take an instantaneous (or Planck time) snapshot of a string, you'd only see a few points of it at once (wherever it intersects at that moment). In reality, if we could detect spatial structure on such small scales at all, we'd see it smeared out spatially (think "camera blur"), not a pure point.
Another way of looking at it is that since all our constituent strings are constantly vibrating in all the higher dimensions, there is no such thing as "our 3D hyperplane" — it's fuzzed out over the higher compact dimensions, so we're never really seeing a specific slice of it.
(In the braneworld scenarios with large extra dimensions, this is somewhat less true: the endpoints of non-gravitational strings are trapped on a specific 3D hyperplane. However, the rest of the string can vibrate a little off of it.)
More concretely, if we could scatter strings off each other at Planck-scale energies in a particle acclerator, their behavior would deviate markedly from that of point particles (basically because strings breaking and merging is a "smoother" process than particles bouncing off each other).
Technically you can "see" the strings, since in string theory every elementary particle is a string. In string theory, any time you detect an electron or a photon, you're looking at a string. It's just that they're so small, we may never be able to tell that they're actually strings and not point particles.
I repeat: So which "natural cycle" is it? It appears you'd rather play conspiracy theorist than provide any evidential support for this claim. If you think there's any reason to believe that it's due to a natural cycle, which cycle is it and what's the evidence?
There is hard evidence showing carbon dioxide concentrations are much lower now than in recent geological ages.
That depends very much on your definition of "recent".
As I said, current levels are higher than they have been in millions of years. We are currently at around 384 ppmv. According to the above link, CO2 hasn't been that high for over 20 million years.
The theory of Catastrophic Anthropogenic Global Warming doesn't predict the current cooling since 1998.
As I pointed out to you in another comment which you ignored, there has not been cooling since 1998, and the decadal trend is within the range of natural variability. (Your linked "evidence", by the way, says nothing specifically about warming or cooling since 1998.)
The hard evidence for an anthropogenic (human) cause for the current warming (which has ceased since 1998
Global warming has not ceased since 1998; the 1998-2007 trend is positive for all major surface data sets. The most recent 10 year trend is lower than average, but this is not particularly surprising on decadal time scales given the interannual variability present; sometimes it's lower, and sometimes it's higher. It needs to be well below average for more like 20 years before you can statistically say there's a real discrepancy.
for this reason)
That's an even more ridiculous claim. The change in solar activity over the last 10 years is relatively quite small. If you want to postulate an unknown feedback which amplifies TSI, you can do so (although you ought to give evidence for it). But that's going to get you into even worse trouble explaining the last 30-40 years of warming, which are totally at odds with the solar trends over that period. You may be tempted to escape that by invoking a lag between the forcing and response, to explain why a flat solar trend can lead to long term warming, but that would directly contradict the idea that the climate will respond quickly over a 10 year time scale to recent changes in solar activity. In short, solar explanations just don't work.
is lacking.
There is plenty of evidence over more than 100 years of instrumental records, which include the late 20th century warming, the stratospheric cooling signature of CO2 (absent for non-greenhouse explanations of surface warming), and the disparity in the day/night warming trends which is predicted by the greenhouse effect but contradicted by solar warming.
Soft evidence, on the other hand, includes computer models of the infinitely complex (and thus un-modelable) climate system
Ah yes, proof by hyperbole.
The climate system is complex. It is not "infinitely complex", and it is certainly not "unmodelable". Models reproduce the major atmospheric and ocean circulation patterns, the spatial and temporal pattern of warming, and a number of other key climate indicators.
that have been tweaked to predict three times the observed "forcing" for the total carbon dioxide in the atmosphere.
To the contrary, observational climate sensitivity estimates are quite in line with model based calculations. There are many problems with Spencer's analysis (which, by the way, is unpublished). His previously published paper with Braswell showed problems with diagnosing climate sensitivity by a model-independent regression of temperature against flux. However, almost nobody uses that method. The standard method is model-data comparison by either bootstrapping or Bayesian parameter estimation; both methods produce similar results, which are in line with GCM predictions. Spencer further speculated, unpublished, that he can diagnose the "true climate sensitivity" by looking at stripes in a temperature-flux regerssion. However, there is no statistical basis or mathematical basis for this claim, and it appears that what it actually diagnoses is the unamplified climate sensitivity, which is not the quantity anybody is interested in.
The human contribution to the total cannot even be accurately measured, but most evidence points to, at the outside, about 5% of the total atmospheric carbon dioxide coming from human sources.
This is the most ridiculous of your statements yet. The strength of human sources relative to natural sources is irrelevant to how much human CO2 ends up in the atmosphere. What matters is the strength of human sources relative to the net balance between natural sources and sinks.
That is, if every year 100 units of natural carbon go into the atmosphere and natural sinks take 100 units out, then there is no net increase or decrease in atmospheric CO2 concentration. If, in addi
...this is much ado about nothing, and can be attributed simply to natural cycles in the weather system.
So which "natural cycle" is it? We've looked at the ones which have caused past climate change (e.g., solar variations, volcanoes, changes in ocean circulation), and ruled them out as the cause of the current warming.
People are so damn self-centered they think anything that happens is a direct result of something they did.
It's not self centered, it's physics. The fact is that we are ramping atmospheric CO2 up to levels not seen in millions of years, its effect on the climate is not negligible.
but seeing how I'm experiencing almost record cold temperatures now for this time of year in my area,
Global warming doesn't predict that every location on Earth gets monotonically hotter every year.
Aerosol geoengineering has a fast response time. We already have a pretty good idea of how strong the cooling effect is, because volcanoes do it all the time. We can gradually dial it up or down, because the climate responds quickly to changes in aerosol optical depth. If the effect is too large, we can dial it down within a few years before anything lasting happens. Accidentally plunging ourselves into an ice age is not a serious risk.
That being said, it's still a bad idea for reasons discussed in TFA, most notably the scenario where we counterbalance the warming for some time and then fail to do it, leading to a large abrupt warming once the cancellation stops.
If it's stratospheric aerosol injection, you turn it off by stopping the injection. All the aerosols will precipitate out within a few years. That's actually the problem with it: it's too easy to turn off. If we fail to keep it going (bad side effects, lack of political will, economic crisis, militarization, etc.), then the counter-cooling rapidly disappears and we abruptly get all the warming we'd have otherwise seen, all compressed into a very short period of time. That's potentially far worse than even the worst-case warming scenarios currently being floated.
The state of the science is: "â¦we do not have a good quantitative understanding of our climate machine and what determines its course. Without the fundamental understanding, it does not seem possible to predict climateâ¦".
Believe it or not, we have learned considerably more about our climate in the last 40 years.
We just launched space probes to try to figure out why the Sun seems so quiet and cool. This was not predicted, nor is it understood.
Since even a return of solar activity to Maunder Minimum levels isn't sufficient to counteract the greenhouse effect over the next century, it's somewhat moot in the long term, barring changes in solar activity that are totally unprecedented in the paleontological record.
The many and varied factors that affect our global climate are thought of but not known.
We know what the major players are (solar irradiance, volcanism, greenhouse gases, industrial aerosols, black carbon, land use changes, the major atmospohere-ocean circulation patterns, snow/ice albedo, clouds). We have a pretty good idea of the relative strengths of each of those effects, too.
We do NOT know enough about the problem to clearly and unequivocally state that reducing CO2 will stop global warming or even control it.
What is the scientific basis for that claim? You embark on a length paen to our ignorance, but as far as I can tell it's a naked assertion. If you read through the latest IPCC report and the literature it cites, you will find we know a great deal about how the climate system operates, and how much various natural and manmade factors contribute to what we observe.
The chances that shifting magnetosphere and solar heating changes have 99.999% of the blame here is as great or greater than the idea that humans have caused this current climate situation.
Sounds like you're not singing our ignorance of the climate anymore. It sounds like you're quite sure what's causing the current warming. Kind of hypocritical if you ask me. If it's manmade, all of a sudden we don't understand anything at all about the climate. If it's natural, then why there's a 99.999% (sure you don't need an extra few 9's there) chance of that being the cause.
That's a pretty bold claim. So, tell me, what is the scientific evidence that "shifting magnetosphere and solar heating changes" are responsible for modern global warming. Please reconcile this with the actual changes in solar irradiance, which on average haven't budged more than a few tenths of a W/m^2 since the 1950s. Explain how this accounts for the observed warming of 0.5 C. Please, be quantitative.
You might want to start by reading, e.g., Foukal et al.'s 2006 review article in Nature on the subject.
The position of this planet and solar system in relation to the surrounding galaxy has an effect on climate.
That's also a pretty bold claim which you failed to support. But that notwithstanding, how much do you think "the position of this planet in relation to the surrounding galaxy" has changed in the last century or so?
There are many factors that affect climate or can, that just won't fit inside the 'standard' activist's head.
"Activists", huh. I see. You want to make this about politics.
Please, tell me, what is the scientific support for your claims?
Understand the problem before you begin thinking you can fix it.
We already understand many of the main aspects of the problem. We don't understand everything, and never will, but that doesn't mean that we know nothing. We know that CO2 has a significant influence on climate, and will have an even larger influence in the future as emissions continue. Solar trends disagree in rate, timing, magnitude, and frequently even in the sign of the effect with the
Natural global warming and global cooling have happened throughout the Earth's history, which is far more than "twice". (Look at the ice age cycles, for instance.) Climatologists know this. It has nothing to do with the evidence that the current warming is not primarily natural, which is based on comparing modern sources of warming and cooling (both natural and manmade) to the spatial and time trend behavior of the climate.
In 1965 and through the 1970s and early 80s, virtually all scientists were Not discussing global warming. They were discussing Global Cooling.
I'm sorry, but the scientific literature disproves your claim. If you don't believe me, go look for yourself at the papers published back then. Web of Knowledge will find them for you. Or just read this paper, written by a group of scientists who got fed up with claim and did a full literature review from 1965-1979. See, in particular, Figure 1. During that period, there was only one year in which cooling papers than warming papers were published (1971), and more warming papers than cooling papers were published in every year after 1971.
In another comment you respond,
I read the article, but I was also ALIVE at that time.
That's nice. Did you read scientific journals back then? Or go to climate conferences? Somehow I doubt it.
The mainstream media isn't the scientific community, and neither was Carl Sagan. Yes, back then some scientists did think that cooling was going to win out. Most of them didn't. The fact is, throughout the 1970s and certainly into the 80s, the scientific community — as measured by the papers they published on the subject — was definitely projecting warming more than cooling.
I agree with your general statements about us being able to do this, but you are making a pretty big assumption saying that you know all of the aspects which control temperature.
It's not that big an assumption, since we've been studying the climate system for over a century now. A source of heating which can raise the global temperature by almost 1 C is not really that negligible. It's hard to miss.
In particular, if the surface is warming up, there are only a few basic options for where the heat could be coming from:
1. More heat could be coming from space. 2. Less heat from space could be reflected away from the surface. 3. More heat from space could be trapped near the surface. 4. More heat could come from the land. 5. More heat could come from the oceans.
1 means solar output. 2 means volcanoes, industrial aerosols, and clouds. 3 means greenhouse gases and clouds. 4 means subterranean heat, industrial activity, biological activity, or (related to 2) surface reflectance from land use changes. 5 means changes in ocean circulation patterns. Actually, I suppose I could add 6, a reorganization of the coupled atmospheric-ocean circulation which changes heat transport.
If you like, I could go into more detail about individual sources. But the upshot is, we've looked in all the places that heat can come from, and it's very difficult to explain the recent changes without appealing to (3), greenhouse gases.
but considering we can hardly predict the weather next week, it is a little silly to think that we know exactly all the factors involved in climate change or can accurately simulate them
Predicting the weather is a very different problem from predicting the climate. I can predict that summer is warmer than winter without predicting chaotic weather dynamics two weeks out. Climate prediction is closer to balancing the global energy budget.
I don't think it's smart to assume we know everything just yet
Nobody assumes we know everything just yet. Have you ever seen the error bars on the IPCC projections of global warming? They are substantial, mostly because we don't have a perfect handle on all the nonlinear feedback effects which may amplify or suppress a source of warming. We do, however, have a pretty good handle on what the basic sources of warming and cooling in the climate system are.
No one knows the magnitude of the heat contribution from any of these mechanisms. It is absolutely asounding how closed your mind is to considering anything beyond CO2 gas in the atmosphere wrt to effects on climate. Personally, I tend to doubt that crustal heat effects are a major contributor to global warming or cooling but my mind is open to the idea, unlike yours.
Could you try to restrain yourself to ordinary levels of jackassery, instead of tremendous jackassery? You're so eager to paint anyone who opposes your beliefs as biased and "closed minded" that you don't even bother to read.
Nowhere have I made the absurd claim that CO2 is the only influence on the climate. In fact, I have explicitly claimed the opposite. What I have claimed is that non-CO2 sources of climate change fail to explain the modern period of global warming. I'm sorry that you are emotionally incapable of accepting the fact that this is well supported by observational evidence and physical theory.
And as I said before, we don't need to theoretically calculate the magnitude of heat contribution from various locations in the mantle/core, etc., when we know from observations that the surface is not receiving increased heat from below. Whatever the contributions add up to, it's de facto small. Have you even bothered to read the reference I cited?
You've rejected variations in solar output, cloud reflectivity, and planetary core heat as factors, not based on any actual data, knowledge, or reason but only because they are not part of your CO2-based theory.
I've rejected them for reasons I've explicitly stated. There is a long literature on each of these subjects, which you would do well to familiarize yourself with. You don't seem particularly interested in reading any of this literature.
Ice core data from Greenland shows that temperatures in Greenland during the Younger Dryas 12,000 years ago were 15C colder than present.
I am well familiar with the Younger Dryas event. My statement is correct. You said "over the last few thousand years".
The Younger Dryas is an extreme event that can not be explained by the current popular CO2 nonsense.
CO2 nonsense, huh? Gee, why don't you get a little more explicit about your biases here? Don't hold back now.
For the Nth time, I have not claimed that all climate change is due to humans. As I pointed out in my very first post to this story, climatologists know that climate has changed naturally in the past for reasons other than anthropogenic CO2. That fact has nothing to do with the evidence that natural sources of climate change are not primarily responsible for the current warming.
In particular, the Younger Dryas event is associated with a reduction in the North Atlantic meridional overturning circulation, probably due to a freshwater pulse into the oceans from Lake Agassiz or another continental source. Climatologists worry that global warming will induce a new MOC weakening due to increased freshwater flux into the North Atlantic. However, changes in the MOC cannot explain the current warming trend, since that would require that the MOC be strengthening when if anything it is weakening (see, e.g., Bryden), and the temperature change would also be primarily concentrated in the North Atlantic (see, e.g., Stocker), which it's not. Not to mention that it wouldn't explain the spatial and temporal pattern of heat penetration into the ocean from the atmosphere, the stratospheric cooling trend, and any number of other lines of evidence.
Obviously the earth's core is a source of heat and obviously it is warming the crust.
I misspoke; I'm used to speaking in terms of temperature anomalies. What I mean is that there is no evidence of increased heat transfer from below. Rather, there is evidence of increased warming from above, i.e., the surface.
If you really think heat is moving from the earth's crustal surface to the core you have a basic misunderstanding of heat transfer concepts and thermodynamics.
The heat anomaly, i.e., change in temperature profile, is moving from the crust to the core. The upper layers have more heat than they used to, but the lower layers don't. This is evidence of increased warming from the surface, not the core.
The age of the ice does matter, because younger Arctic sea ice tends to be thinner, and is therefore lest likely to persist from year to year. Warming slowly wears away the thick multiyear ice. When that's gone, we could have no sea ice in the Arctic during the summer. Some young thin ice could form during the winter and then melt away again the next summer.
I didn't use historic knowledge, meaning knowledge of the climate before the modern instrumental record. We've been watching the climate change and at the same time we've been watching the natural and human sources of climate change. My point is that we don't need knowledge of natural cycles from preceding centuries to know that the recent warming is not entirely natural. That's because attribution of the recent warming to human causes is not based simply on that warming being anomalous in a natural context. It's because the recent natural sources of warming don't agree with it: the natural cycles which we measure don't explain it.
Yes. As I said, stochastic fluctuations in clouds as related to climate have been studied since the 1970s. Radiometric studies of Earth albedo go back to the 1960s, The Earthshine data is more recent.
If you read the paper associated with your link, you find that they don't use the cloud albedo changes to explain long term trends in global warming. Rather, they speculate whether the warming has caused, and will cause, future cloud albedo changes. You might want to read Evan et al.'s followup GRL piece.
The historical record shows that global temperatures have swung to great extremes over just the last few thousand years.
No, it doesn't. At best it shows maybe 1 C fluctuations spread out over multiple centuries.
and are therefore obviously affected by variables other than CO2
I've already mentioned many times that we know the climate is affected by variables other than CO2. The problem is that those variables don't explain the current changes.
Interesting that you're willing to let "deep borehole measurements" made at a handful of locations be a proxy for planetary core heat release but you're unwilling to let a much larger and better set of ocean temperature measurements be a similar proxy for global surface temperatures.
Ocean temperature measurements aren't a proxy for global surface temperatures. They are a proxy for ocean heat absorption. I have stated quite clearly that ocean temperature observations DO measure the absorption of heat into the oceans, and that we see a long term signal in that heat uptake which indicates that the oceans are heating from the surface down. I have also said that the year to year measurements of ocean heat are very noisy, meaning that it's extremely difficult to tell in any given year what the net heat flux is. It's only over decades that we can see the trend.
We don't know what mechanisms predominate in the release of heat from the core, how the mantle circulates, or even what the source of heat is from the core but you are willing to flat out state that it's of no significance, based on a handful of borehole measurements,
Uh, yeah. The surface isn't receiving substantial heat from below because it's not warming from below. You can't get any more clear than that. The processes responsible for core heating or cooling are irrelevant to this observational fact.
just as Lord Kelvin was willing to state a few years back that the Earth could only be 4,000 years old based on his modelling of heat release from the core.
This has nothing to do with modeling. It's a direct observation: we don't see heat moving up from the core toward the surface. We see the opposite.
This is an improvement for you, at least and is really the only way you can possibly explain away the increase in sea ice cover described in TFA
I don't need to appeal to ocean heat to account for changes in sea ice. The factors influencing sea ice extent are even noisier than ocean temperature fluctuations; there are also fluctuations in atmospheric circulation, ocean convection to different latitudes, the aforementioned cloud cover, and so on. The fact is, 1- or 2-year trends in sea ice mean hardly anything, either in one direction or the other. Compared to 10-20 years ago, that's a statistically significant difference. Over one year, it's noise.
It's not misleading; summer minimum ice extent and annual ice extent are two different quantities, both of which are interesting and climatically relevant.
That, frankly, is preposterous. How can you define what constitutes "odd", if you don't know what's normal first?
We know, because we can directly compare what is happening to the aspects of the climate system which control temperature.
Our attribution of global warming to humans is not based solely or even primarily on saying it's "odd" within a historical context. The enhanced greenhouse effect was predicted in the 19th century on general physical principles, before we had decent historical records. The current warming is "odd" within the context of measured natural sources warming.
To overuse a cliche, if you want to know whether a forest fire was started by lightning or campfire, it's not sufficient to merely see whether it's odd to have forest fires in that area. That doesn't answer the attribution quesiton, although fires in an unusual place can be suspicious. What you do is look for more direct evidence, like whether there was lightning that day, or if there are matches nearby.
Even if there was some natural warming even in the past that looked just like the one today, that doesn't change the evidence we have that today's warming is not due to natural causes. That's because we can actually go and look at the natural causes. We see that solar output hasn't changed in 50-60 years, right when we experienced the most warming. We see that volcanic activity hasn't dramatically dropped off in recent decades. We see that the oceans are warming from the top down, so the heat isn't coming from the oceans. We see that fluctuations in cloud cover exist, but don't have a sustained trend large enough to explain what we see. And so on. When we look at the greenhouse effect, it's large enough, it has the right timing, and it has a unique fingerprint (stratospheric cooling) which differs from natural sources of warming.
We know something like 0.0001% of what there is to know about climate
Oh sure, see if you can win an argument by fabricating numbers. Do we know 90% of what there is to know? 50% 1% 0.1% 0.01%? Just make up a small enough number and flaunt it as if that represented what we really know about the climate, and you're sure to rest your case.
I'm sorry, we've been studying the climate for over a century now, and we know quite a bit about what goes on inside it and where heat can come from. Waving your hands and saying "maybe it's a natural cycle" doesn't cut it in science. The problem is that we've looked at the natural cycles, and they're not doing what is necessary to produce the warming we see. We look in the atmosphere, we look in the oceans, we look in space, we look in the biosphere, and there just isn't another large source of heat there.
If we have 200 years of data (which we only kinda have) we can't know anything about how often this type of shift happened in the past. Perhaps its all just one 400 year cycle? Without historic trends you cannot say a dam thing about current trends.
That's wrong, because we don't have to rely on just looking at temperature trend data. With modern instrumental capabilities, we can actually look at CAUSES of climate change. Skeptics love to suggest that it's all just a "natural cycle", but natural cycles, like anything else, have causes. Past climate cycles have been due to things like variations in solar output, volcanic activity, changes in global ocean circulation, etc. Today we can measure solar output, volcanic activity, ocean circulation patterns, cloud cover, greenhouse gases, etc., and see the extent to which each one can explain what's going on. We don't have to just rely on whether the modern warming is anomalous or not in a historical context. Indeed, even if bigger/faster changes happened in the past, that still doesn't mean the current warming is "a natural cycle". Yes, climate has changed naturally in the past, but that doesn't change the evidence that the CURRENT change can't be explained by appealing to primarily natural causes.
Really this is science 101.
Speaking as a physicist, I don't need you to lecture me on what science is. Maybe if you applied a small amount of thought to the subject you'd understand that climate science is based on more than simply saying, "Huh, that looks like a big change".
In fact there are almost no climatologist that claim all the warming is man made. Its quite widely accepted that at least some is very natural warming.
I didn't claim otherwise. I'm pointing out that you can't explain the data if you think CO2 is a relatively small contributor.
The is also a general view that future warming will also be part natural and part man made.
We don't know whether future natural forcings will cause warming or cooling. We do believe that as CO2 levels continue to go up, the man made influence will continue to become relatively stronger than natural sources in either direction, barring something really extreme.
Read more than news papers please.
Why don't you? Try Tomassini et al.'s paper last year in J. Climate for a modern estimate of the relative natural and anthropogenic forcings and their uncertainties.
Slashdot Mirror
The tidal force isn't too much different, relativistically. Dimensionally the tidal force still has to look something like GMm/R^3 deltaR. I looked up the relativistic calculation in Misner, Thorne, and Wheeler (in Section 32.6, with the charming running title "Gore at the singularity). There should be a 1/4 in front of that expression. The horizontal compression in any direction is half that of the vertical tension. I am no expert on what that would do to a star.
No. No amount of pressure can prevent a collapsing universe from collapsing; that's the content of various cosmological singularity theorems. This doesn't even prevent simple things like galaxies colliding. It really only works because a black hole event horizon is relatively small, and it's hard for a lot of matter to all cram in. But in a collapsing universe, once you get to the point that things are starting to collide, the collapse has already built up enough that it's unstoppable. Past a certain point, pressure itself gravitates more than it repels. That's why black hole collapse is inevitable beyond a certain critical mass.
Regarding your thought experiment: the cosmic microwave background radiation is a much larger influx than the Hawking radiation outflux of any stellar (or larger) black hole. So unless the black hole is isolated from the rest of the universe, it will always grow from cosmic radiation, even if no matter falls in. (Or at least until the universe expands enough that the background radiation becomes cooler than Hawking radiation; see here, in the second half.)
Well, I'll admit this sounds intuitive with the Penrose-Hawking singularity theorems applied to the Big Bang.
No, it has nothing to do with singularities (or the Big Bang). It has more to do with matter which orbits black holes.
Now, I'm not a physicist either but I have read a lot that speculates the Big Bang was a singularity that created a hot unstable mess. All the mass of the universe in a singularity suddenly starts blowing out and producing massive heat. Although what was around this singularity is nothing--not even space.
Don't think of the singularity as a point that blew matter in all directions. As you correctly note, there is nothing "around" a singularity. For now limit consideration to an infinite universe, which is preferred by standard inflation scnearios. Then a singularity isn't even really a single point. The universe is still infinite in extent, it's just that the matter/energy in it is of infinite density. (See here.) Think of the Big Bang as where space expands making the matter less dense, rather than some single location that spews matter away from itself.
As always, it brings up interesting questions about what was before that epoch since it is kind of clear that such a singularity could not be possibly be stable for any amount of time (as this research indicates).
To reiterate, this research has nothing to do with the singularity inside of black holes. It has to do with matter which is outside black holes not being able to make its way in, due to the pressure created by other infalling matter. The black hole itself does not emit any appreciable matter/radiation (other than a very tiny amount of Hawking radiation).
All I could think of was that I really wish they called micro black holes that exist for minute fractions of a second something other than "black holes." It scares people unnaturally.
I agree. "Micro black hole" is a terrible name. I prefer "Death, Tiny Destroyer of Worlds".
Strictly and classically speaking, that's correct. However, since the string is always vibrating, you're going to see more or less its full extent in our 3D space as different parts of it pass through our 3D hyperplane at nearby instants of time. If you could take an instantaneous (or Planck time) snapshot of a string, you'd only see a few points of it at once (wherever it intersects at that moment). In reality, if we could detect spatial structure on such small scales at all, we'd see it smeared out spatially (think "camera blur"), not a pure point.
Another way of looking at it is that since all our constituent strings are constantly vibrating in all the higher dimensions, there is no such thing as "our 3D hyperplane" — it's fuzzed out over the higher compact dimensions, so we're never really seeing a specific slice of it.
(In the braneworld scenarios with large extra dimensions, this is somewhat less true: the endpoints of non-gravitational strings are trapped on a specific 3D hyperplane. However, the rest of the string can vibrate a little off of it.)
More concretely, if we could scatter strings off each other at Planck-scale energies in a particle acclerator, their behavior would deviate markedly from that of point particles (basically because strings breaking and merging is a "smoother" process than particles bouncing off each other).
Technically you can "see" the strings, since in string theory every elementary particle is a string. In string theory, any time you detect an electron or a photon, you're looking at a string. It's just that they're so small, we may never be able to tell that they're actually strings and not point particles.
Oh? Who, I ask, ruled them out?
I repeat: So which "natural cycle" is it? It appears you'd rather play conspiracy theorist than provide any evidential support for this claim. If you think there's any reason to believe that it's due to a natural cycle, which cycle is it and what's the evidence?
And by the way: citing Monckton? Give me a break.
On what evidence do you base this claim?
Try this.
There is hard evidence showing carbon dioxide concentrations are much lower now than in recent geological ages.
That depends very much on your definition of "recent".
As I said, current levels are higher than they have been in millions of years. We are currently at around 384 ppmv. According to the above link, CO2 hasn't been that high for over 20 million years.
The theory of Catastrophic Anthropogenic Global Warming doesn't predict the current cooling since 1998.
As I pointed out to you in another comment which you ignored, there has not been cooling since 1998, and the decadal trend is within the range of natural variability. (Your linked "evidence", by the way, says nothing specifically about warming or cooling since 1998.)
The hard evidence for an anthropogenic (human) cause for the current warming (which has ceased since 1998
Global warming has not ceased since 1998; the 1998-2007 trend is positive for all major surface data sets. The most recent 10 year trend is lower than average, but this is not particularly surprising on decadal time scales given the interannual variability present; sometimes it's lower, and sometimes it's higher. It needs to be well below average for more like 20 years before you can statistically say there's a real discrepancy.
for this reason)
That's an even more ridiculous claim. The change in solar activity over the last 10 years is relatively quite small. If you want to postulate an unknown feedback which amplifies TSI, you can do so (although you ought to give evidence for it). But that's going to get you into even worse trouble explaining the last 30-40 years of warming, which are totally at odds with the solar trends over that period. You may be tempted to escape that by invoking a lag between the forcing and response, to explain why a flat solar trend can lead to long term warming, but that would directly contradict the idea that the climate will respond quickly over a 10 year time scale to recent changes in solar activity. In short, solar explanations just don't work.
is lacking.
There is plenty of evidence over more than 100 years of instrumental records, which include the late 20th century warming, the stratospheric cooling signature of CO2 (absent for non-greenhouse explanations of surface warming), and the disparity in the day/night warming trends which is predicted by the greenhouse effect but contradicted by solar warming.
Soft evidence, on the other hand, includes computer models of the infinitely complex (and thus un-modelable) climate system
Ah yes, proof by hyperbole.
The climate system is complex. It is not "infinitely complex", and it is certainly not "unmodelable". Models reproduce the major atmospheric and ocean circulation patterns, the spatial and temporal pattern of warming, and a number of other key climate indicators.
that have been tweaked to predict three times the observed "forcing" for the total carbon dioxide in the atmosphere.
To the contrary, observational climate sensitivity estimates are quite in line with model based calculations. There are many problems with Spencer's analysis (which, by the way, is unpublished). His previously published paper with Braswell showed problems with diagnosing climate sensitivity by a model-independent regression of temperature against flux. However, almost nobody uses that method. The standard method is model-data comparison by either bootstrapping or Bayesian parameter estimation; both methods produce similar results, which are in line with GCM predictions. Spencer further speculated, unpublished, that he can diagnose the "true climate sensitivity" by looking at stripes in a temperature-flux regerssion. However, there is no statistical basis or mathematical basis for this claim, and it appears that what it actually diagnoses is the unamplified climate sensitivity, which is not the quantity anybody is interested in.
The human contribution to the total cannot even be accurately measured, but most evidence points to, at the outside, about 5% of the total atmospheric carbon dioxide coming from human sources.
This is the most ridiculous of your statements yet. The strength of human sources relative to natural sources is irrelevant to how much human CO2 ends up in the atmosphere. What matters is the strength of human sources relative to the net balance between natural sources and sinks.
That is, if every year 100 units of natural carbon go into the atmosphere and natural sinks take 100 units out, then there is no net increase or decrease in atmospheric CO2 concentration. If, in addi
...this is much ado about nothing, and can be attributed simply to natural cycles in the weather system.
So which "natural cycle" is it? We've looked at the ones which have caused past climate change (e.g., solar variations, volcanoes, changes in ocean circulation), and ruled them out as the cause of the current warming.
People are so damn self-centered they think anything that happens is a direct result of something they did.
It's not self centered, it's physics. The fact is that we are ramping atmospheric CO2 up to levels not seen in millions of years, its effect on the climate is not negligible.
but seeing how I'm experiencing almost record cold temperatures now for this time of year in my area,
Global warming doesn't predict that every location on Earth gets monotonically hotter every year.
Aerosol geoengineering has a fast response time. We already have a pretty good idea of how strong the cooling effect is, because volcanoes do it all the time. We can gradually dial it up or down, because the climate responds quickly to changes in aerosol optical depth. If the effect is too large, we can dial it down within a few years before anything lasting happens. Accidentally plunging ourselves into an ice age is not a serious risk.
That being said, it's still a bad idea for reasons discussed in TFA, most notably the scenario where we counterbalance the warming for some time and then fail to do it, leading to a large abrupt warming once the cancellation stops.
If it's stratospheric aerosol injection, you turn it off by stopping the injection. All the aerosols will precipitate out within a few years. That's actually the problem with it: it's too easy to turn off. If we fail to keep it going (bad side effects, lack of political will, economic crisis, militarization, etc.), then the counter-cooling rapidly disappears and we abruptly get all the warming we'd have otherwise seen, all compressed into a very short period of time. That's potentially far worse than even the worst-case warming scenarios currently being floated.
The state of the science is: "â¦we do not have a good quantitative understanding of our climate machine and what determines its course. Without the fundamental understanding, it does not seem possible to predict climateâ¦".
Believe it or not, we have learned considerably more about our climate in the last 40 years.
We just launched space probes to try to figure out why the Sun seems so quiet and cool. This was not predicted, nor is it understood.
Since even a return of solar activity to Maunder Minimum levels isn't sufficient to counteract the greenhouse effect over the next century, it's somewhat moot in the long term, barring changes in solar activity that are totally unprecedented in the paleontological record.
The many and varied factors that affect our global climate are thought of but not known.
We know what the major players are (solar irradiance, volcanism, greenhouse gases, industrial aerosols, black carbon, land use changes, the major atmospohere-ocean circulation patterns, snow/ice albedo, clouds). We have a pretty good idea of the relative strengths of each of those effects, too.
We do NOT know enough about the problem to clearly and unequivocally state that reducing CO2 will stop global warming or even control it.
What is the scientific basis for that claim? You embark on a length paen to our ignorance, but as far as I can tell it's a naked assertion. If you read through the latest IPCC report and the literature it cites, you will find we know a great deal about how the climate system operates, and how much various natural and manmade factors contribute to what we observe.
The chances that shifting magnetosphere and solar heating changes have 99.999% of the blame here is as great or greater than the idea that humans have caused this current climate situation.
Sounds like you're not singing our ignorance of the climate anymore. It sounds like you're quite sure what's causing the current warming. Kind of hypocritical if you ask me. If it's manmade, all of a sudden we don't understand anything at all about the climate. If it's natural, then why there's a 99.999% (sure you don't need an extra few 9's there) chance of that being the cause.
That's a pretty bold claim. So, tell me, what is the scientific evidence that "shifting magnetosphere and solar heating changes" are responsible for modern global warming. Please reconcile this with the actual changes in solar irradiance, which on average haven't budged more than a few tenths of a W/m^2 since the 1950s. Explain how this accounts for the observed warming of 0.5 C. Please, be quantitative.
You might want to start by reading, e.g., Foukal et al.'s 2006 review article in Nature on the subject.
The position of this planet and solar system in relation to the surrounding galaxy has an effect on climate.
That's also a pretty bold claim which you failed to support. But that notwithstanding, how much do you think "the position of this planet in relation to the surrounding galaxy" has changed in the last century or so?
There are many factors that affect climate or can, that just won't fit inside the 'standard' activist's head.
"Activists", huh. I see. You want to make this about politics.
Please, tell me, what is the scientific support for your claims?
Understand the problem before you begin thinking you can fix it.
We already understand many of the main aspects of the problem. We don't understand everything, and never will, but that doesn't mean that we know nothing. We know that CO2 has a significant influence on climate, and will have an even larger influence in the future as emissions continue. Solar trends disagree in rate, timing, magnitude, and frequently even in the sign of the effect with the
You have any other strawmen you want to attack?
Natural global warming and global cooling have happened throughout the Earth's history, which is far more than "twice". (Look at the ice age cycles, for instance.) Climatologists know this. It has nothing to do with the evidence that the current warming is not primarily natural, which is based on comparing modern sources of warming and cooling (both natural and manmade) to the spatial and time trend behavior of the climate.
In 1965 and through the 1970s and early 80s, virtually all scientists were Not discussing global warming. They were discussing Global Cooling.
I'm sorry, but the scientific literature disproves your claim. If you don't believe me, go look for yourself at the papers published back then. Web of Knowledge will find them for you. Or just read this paper, written by a group of scientists who got fed up with claim and did a full literature review from 1965-1979. See, in particular, Figure 1. During that period, there was only one year in which cooling papers than warming papers were published (1971), and more warming papers than cooling papers were published in every year after 1971.
In another comment you respond,
I read the article, but I was also ALIVE at that time.
That's nice. Did you read scientific journals back then? Or go to climate conferences? Somehow I doubt it.
The mainstream media isn't the scientific community, and neither was Carl Sagan. Yes, back then some scientists did think that cooling was going to win out. Most of them didn't. The fact is, throughout the 1970s and certainly into the 80s, the scientific community — as measured by the papers they published on the subject — was definitely projecting warming more than cooling.
I agree with your general statements about us being able to do this, but you are making a pretty big assumption saying that you know all of the aspects which control temperature.
It's not that big an assumption, since we've been studying the climate system for over a century now. A source of heating which can raise the global temperature by almost 1 C is not really that negligible. It's hard to miss.
In particular, if the surface is warming up, there are only a few basic options for where the heat could be coming from:
1. More heat could be coming from space.
2. Less heat from space could be reflected away from the surface.
3. More heat from space could be trapped near the surface.
4. More heat could come from the land.
5. More heat could come from the oceans.
1 means solar output. 2 means volcanoes, industrial aerosols, and clouds. 3 means greenhouse gases and clouds. 4 means subterranean heat, industrial activity, biological activity, or (related to 2) surface reflectance from land use changes. 5 means changes in ocean circulation patterns. Actually, I suppose I could add 6, a reorganization of the coupled atmospheric-ocean circulation which changes heat transport.
If you like, I could go into more detail about individual sources. But the upshot is, we've looked in all the places that heat can come from, and it's very difficult to explain the recent changes without appealing to (3), greenhouse gases.
but considering we can hardly predict the weather next week, it is a little silly to think that we know exactly all the factors involved in climate change or can accurately simulate them
Predicting the weather is a very different problem from predicting the climate. I can predict that summer is warmer than winter without predicting chaotic weather dynamics two weeks out. Climate prediction is closer to balancing the global energy budget.
I don't think it's smart to assume we know everything just yet
Nobody assumes we know everything just yet. Have you ever seen the error bars on the IPCC projections of global warming? They are substantial, mostly because we don't have a perfect handle on all the nonlinear feedback effects which may amplify or suppress a source of warming. We do, however, have a pretty good handle on what the basic sources of warming and cooling in the climate system are.
By the way:
No one knows the magnitude of the heat contribution from any of these mechanisms. It is absolutely asounding how closed your mind is to considering anything beyond CO2 gas in the atmosphere wrt to effects on climate. Personally, I tend to doubt that crustal heat effects are a major contributor to global warming or cooling but my mind is open to the idea, unlike yours.
Could you try to restrain yourself to ordinary levels of jackassery, instead of tremendous jackassery? You're so eager to paint anyone who opposes your beliefs as biased and "closed minded" that you don't even bother to read.
Nowhere have I made the absurd claim that CO2 is the only influence on the climate. In fact, I have explicitly claimed the opposite. What I have claimed is that non-CO2 sources of climate change fail to explain the modern period of global warming. I'm sorry that you are emotionally incapable of accepting the fact that this is well supported by observational evidence and physical theory.
And as I said before, we don't need to theoretically calculate the magnitude of heat contribution from various locations in the mantle/core, etc., when we know from observations that the surface is not receiving increased heat from below. Whatever the contributions add up to, it's de facto small. Have you even bothered to read the reference I cited?
You've rejected variations in solar output, cloud reflectivity, and planetary core heat as factors, not based on any actual data, knowledge, or reason but only because they are not part of your CO2-based theory.
I've rejected them for reasons I've explicitly stated. There is a long literature on each of these subjects, which you would do well to familiarize yourself with. You don't seem particularly interested in reading any of this literature.
Ice core data from Greenland shows that temperatures in Greenland during the Younger Dryas 12,000 years ago were 15C colder than present.
I am well familiar with the Younger Dryas event. My statement is correct. You said "over the last few thousand years".
The Younger Dryas is an extreme event that can not be explained by the current popular CO2 nonsense.
CO2 nonsense, huh? Gee, why don't you get a little more explicit about your biases here? Don't hold back now.
For the Nth time, I have not claimed that all climate change is due to humans. As I pointed out in my very first post to this story, climatologists know that climate has changed naturally in the past for reasons other than anthropogenic CO2. That fact has nothing to do with the evidence that natural sources of climate change are not primarily responsible for the current warming.
In particular, the Younger Dryas event is associated with a reduction in the North Atlantic meridional overturning circulation, probably due to a freshwater pulse into the oceans from Lake Agassiz or another continental source. Climatologists worry that global warming will induce a new MOC weakening due to increased freshwater flux into the North Atlantic. However, changes in the MOC cannot explain the current warming trend, since that would require that the MOC be strengthening when if anything it is weakening (see, e.g., Bryden), and the temperature change would also be primarily concentrated in the North Atlantic (see, e.g., Stocker), which it's not. Not to mention that it wouldn't explain the spatial and temporal pattern of heat penetration into the ocean from the atmosphere, the stratospheric cooling trend, and any number of other lines of evidence.
Obviously the earth's core is a source of heat and obviously it is warming the crust.
I misspoke; I'm used to speaking in terms of temperature anomalies. What I mean is that there is no evidence of increased heat transfer from below. Rather, there is evidence of increased warming from above, i.e., the surface.
If you really think heat is moving from the earth's crustal surface to the core you have a basic misunderstanding of heat transfer concepts and thermodynamics.
The heat anomaly, i.e., change in temperature profile, is moving from the crust to the core. The upper layers have more heat than they used to, but the lower layers don't. This is evidence of increased warming from the surface, not the core.
Ah yes. When all else false, resort to global conspiracy.
When you want to discuss some scientific evidence, let me know. (No, I'm not going to watch a video, but you can summarize it if you like.)
The age of the ice does matter, because younger Arctic sea ice tends to be thinner, and is therefore lest likely to persist from year to year. Warming slowly wears away the thick multiyear ice. When that's gone, we could have no sea ice in the Arctic during the summer. Some young thin ice could form during the winter and then melt away again the next summer.
I didn't use historic knowledge, meaning knowledge of the climate before the modern instrumental record. We've been watching the climate change and at the same time we've been watching the natural and human sources of climate change. My point is that we don't need knowledge of natural cycles from preceding centuries to know that the recent warming is not entirely natural. That's because attribution of the recent warming to human causes is not based simply on that warming being anomalous in a natural context. It's because the recent natural sources of warming don't agree with it: the natural cycles which we measure don't explain it.
Did you read the link I provided?
Yes. As I said, stochastic fluctuations in clouds as related to climate have been studied since the 1970s. Radiometric studies of Earth albedo go back to the 1960s, The Earthshine data is more recent.
If you read the paper associated with your link, you find that they don't use the cloud albedo changes to explain long term trends in global warming. Rather, they speculate whether the warming has caused, and will cause, future cloud albedo changes. You might want to read Evan et al.'s followup GRL piece.
The historical record shows that global temperatures have swung to great extremes over just the last few thousand years.
No, it doesn't. At best it shows maybe 1 C fluctuations spread out over multiple centuries.
and are therefore obviously affected by variables other than CO2
I've already mentioned many times that we know the climate is affected by variables other than CO2. The problem is that those variables don't explain the current changes.
Interesting that you're willing to let "deep borehole measurements" made at a handful of locations be a proxy for planetary core heat release but you're unwilling to let a much larger and better set of ocean temperature measurements be a similar proxy for global surface temperatures.
Ocean temperature measurements aren't a proxy for global surface temperatures. They are a proxy for ocean heat absorption. I have stated quite clearly that ocean temperature observations DO measure the absorption of heat into the oceans, and that we see a long term signal in that heat uptake which indicates that the oceans are heating from the surface down. I have also said that the year to year measurements of ocean heat are very noisy, meaning that it's extremely difficult to tell in any given year what the net heat flux is. It's only over decades that we can see the trend.
We don't know what mechanisms predominate in the release of heat from the core, how the mantle circulates, or even what the source of heat is from the core but you are willing to flat out state that it's of no significance, based on a handful of borehole measurements,
Uh, yeah. The surface isn't receiving substantial heat from below because it's not warming from below. You can't get any more clear than that. The processes responsible for core heating or cooling are irrelevant to this observational fact.
just as Lord Kelvin was willing to state a few years back that the Earth could only be 4,000 years old based on his modelling of heat release from the core.
This has nothing to do with modeling. It's a direct observation: we don't see heat moving up from the core toward the surface. We see the opposite.
This is an improvement for you, at least and is really the only way you can possibly explain away the increase in sea ice cover described in TFA
I don't need to appeal to ocean heat to account for changes in sea ice. The factors influencing sea ice extent are even noisier than ocean temperature fluctuations; there are also fluctuations in atmospheric circulation, ocean convection to different latitudes, the aforementioned cloud cover, and so on. The fact is, 1- or 2-year trends in sea ice mean hardly anything, either in one direction or the other. Compared to 10-20 years ago, that's a statistically significant difference. Over one year, it's noise.
It's not misleading; summer minimum ice extent and annual ice extent are two different quantities, both of which are interesting and climatically relevant.
That, frankly, is preposterous. How can you define what constitutes "odd", if you don't know what's normal first?
We know, because we can directly compare what is happening to the aspects of the climate system which control temperature.
Our attribution of global warming to humans is not based solely or even primarily on saying it's "odd" within a historical context. The enhanced greenhouse effect was predicted in the 19th century on general physical principles, before we had decent historical records. The current warming is "odd" within the context of measured natural sources warming.
To overuse a cliche, if you want to know whether a forest fire was started by lightning or campfire, it's not sufficient to merely see whether it's odd to have forest fires in that area. That doesn't answer the attribution quesiton, although fires in an unusual place can be suspicious. What you do is look for more direct evidence, like whether there was lightning that day, or if there are matches nearby.
Even if there was some natural warming even in the past that looked just like the one today, that doesn't change the evidence we have that today's warming is not due to natural causes. That's because we can actually go and look at the natural causes. We see that solar output hasn't changed in 50-60 years, right when we experienced the most warming. We see that volcanic activity hasn't dramatically dropped off in recent decades. We see that the oceans are warming from the top down, so the heat isn't coming from the oceans. We see that fluctuations in cloud cover exist, but don't have a sustained trend large enough to explain what we see. And so on. When we look at the greenhouse effect, it's large enough, it has the right timing, and it has a unique fingerprint (stratospheric cooling) which differs from natural sources of warming.
We know something like 0.0001% of what there is to know about climate
Oh sure, see if you can win an argument by fabricating numbers. Do we know 90% of what there is to know? 50% 1% 0.1% 0.01%? Just make up a small enough number and flaunt it as if that represented what we really know about the climate, and you're sure to rest your case.
I'm sorry, we've been studying the climate for over a century now, and we know quite a bit about what goes on inside it and where heat can come from. Waving your hands and saying "maybe it's a natural cycle" doesn't cut it in science. The problem is that we've looked at the natural cycles, and they're not doing what is necessary to produce the warming we see. We look in the atmosphere, we look in the oceans, we look in space, we look in the biosphere, and there just isn't another large source of heat there.
If we have 200 years of data (which we only kinda have) we can't know anything about how often this type of shift happened in the past. Perhaps its all just one 400 year cycle? Without historic trends you cannot say a dam thing about current trends.
That's wrong, because we don't have to rely on just looking at temperature trend data. With modern instrumental capabilities, we can actually look at CAUSES of climate change. Skeptics love to suggest that it's all just a "natural cycle", but natural cycles, like anything else, have causes. Past climate cycles have been due to things like variations in solar output, volcanic activity, changes in global ocean circulation, etc. Today we can measure solar output, volcanic activity, ocean circulation patterns, cloud cover, greenhouse gases, etc., and see the extent to which each one can explain what's going on. We don't have to just rely on whether the modern warming is anomalous or not in a historical context. Indeed, even if bigger/faster changes happened in the past, that still doesn't mean the current warming is "a natural cycle". Yes, climate has changed naturally in the past, but that doesn't change the evidence that the CURRENT change can't be explained by appealing to primarily natural causes.
Really this is science 101.
Speaking as a physicist, I don't need you to lecture me on what science is. Maybe if you applied a small amount of thought to the subject you'd understand that climate science is based on more than simply saying, "Huh, that looks like a big change".
In fact there are almost no climatologist that claim all the warming is man made. Its quite widely accepted that at least some is very natural warming.
I didn't claim otherwise. I'm pointing out that you can't explain the data if you think CO2 is a relatively small contributor.
The is also a general view that future warming will also be part natural and part man made.
We don't know whether future natural forcings will cause warming or cooling. We do believe that as CO2 levels continue to go up, the man made influence will continue to become relatively stronger than natural sources in either direction, barring something really extreme.
Read more than news papers please.
Why don't you? Try Tomassini et al.'s paper last year in J. Climate for a modern estimate of the relative natural and anthropogenic forcings and their uncertainties.