That’s not what such parameters would be used for. Please re-read what I posted.
That doesn’t make any sense to me. Anyway, please give me a cite that somebody has proposed the hypothesis that cosmic rays amplify the effects of solar irradiance. And please tell me what evidence would support such a hypothesis.
I’ve lost your point on all this.
Here is a BCC article that talks about it. As for the evidence supporting it, I’ll let you dig it up since I don’t find the hypothesis all that compelling myself (at least as a major explanation of the current warming…whether or not cosmic rays have some effect on climate in general seems like an open question).
Please read my posts before you respond to them. Yes, you’ve missed the point.
Bottom line: There is plenty of potential for the tuning problems I discussed.
I see nothing in that article about cosmic rays amplifying the effects of solar irradiance. Could you quote the part of the article you are referring to?
I’m asking what evidence would support this mysterious hypothesis, not what evidence does support it. Thus, no digging is required.
I’m still around; I’ve been busy but I should be able to get back to this sometime this week.
And another question:
Isn’t that a fancy way of saying that if you compare the levels of solar irradiance through the 20th century with global temperatures, the two graphs won’t match up very well?
Reading your posts doesn’t help that much. As for your bottom line, I don’t see how you have made this case at all.
Well, like I said in the previous post, perhaps “solar activity” would be a slightly better word to use although I don’t think it is really wrong to say the irradiance or luminosity. As for the discussion of this in that article, try this:
Well, a reasonably good correlation between solar activity (and/or cosmic ray intensity) and global temperatures that includes the last ~30 years would be one thing. More detailed understanding of the mechanism and an ability to at least estimate its effect with modeling would be another.
More or less…but what is most relevant is that there is not a very good match for the last ~30 years or so. Before that time, there is a better match, suggesting that solar irradiance was certainly an important factor up through the middle of the 20th century or so but can’t explain any significant amount of the warming after that.
And I’m not sure this questions can reasonably be answered without more data. How far off was the model before the volcanic and solar terms were changed? How large is the mismatch after the CO2 forcing is removed? Where do all of the mismatches occur (volcanic, solar, CO2)?
I think I had better amend this sentence a bit after some further study. In fact, it is probably unfair to say as a fact that there “were some scientists who were presenting alarmist worries about global cooling”. All that I can find so far in the peer-reviewed literature…and looking at other sources that have studied the peer-reviewed literature (see, e.g., here and here)…are a few papers that soberly discussed the various possibilities of warming due to CO2 or cooling due to aerosols (or, on a much longer timescale, cooling due to the normal orbital mechanisms that lead to ice ages). There is, in fact, no peer-reviewed paper that I have yet found that could really be interpreted as “alarmist” in regards to the possibility of global cooling. This is not to say that no such paper exists…but it does suggest that any such papers were, at best, very few and far between.
In the popular press, there were a few alarmist articles or books such as a 1975 Newsweek article and a 1977 book entitled “The Weather Conspiracy: The Coming of the New Ice Age”, which was justifiably panned by scientist Stephen Schneider in a review in Nature (and there was apparently another also referred to in that article entitled “The Cooling”).
So, in summary, I have to say that upon further investigation, there is much less than even I had thought to the “global cooling myth”. I had expected that there were at least a few scientists who made some alarmist predictions about global cooling in peer-reviewed papers, even while more sober assessments such as that of the National Academy of Sciences then clearly stated that the future course of climate could not yet be predicted. In fact, it seems that even these apparent alarmist predictions by a few scientists are imaginary (or, at least, so far undiscovered) and that, in fact, we can really only look to the popular press for any alarmism on this score.
What exactly do you not understand about post #228?
I still don’t see anything about amplification of the effects of solar activity. Why not just quote the part you are referring to? (Or admit that you can’t back up your claim.)
Makes sense. But it seems to me that similar criticisms could be made of CO2.
I think I summarized the problems with it pretty well in post #229.
Man…oh man. Just look at what I quoted: “Their theory holds that cosmic rays help clouds to form by providing tiny particles around which water vapour can condense. Overall, clouds cool the Earth. During periods of active solar activity, cosmic rays are partially blocked by the Sun’s more intense magnetic field. Cloud formation diminishes, and the Earth warms.” So, this is a mechanism by which the effects of solar activity could potentially be amplified. Maybe you are getting hung up on the word “amplified”? The idea is that through this mechanism it is potentially possible for the global temperature to respond to changes in solar activity by an amount larger than one would expect based on computing the direct radiative forcing due to the change in the sun’s energy striking the earth. Thus, “amplified” seems like a reasonable word to use.
No. It could not. In fact, including the forcing due to CO2 is the only known way to get good agreement between the global temperature record and the modeled temperature record over a period that includes the last ~30 years.
That’s not an answer to my question. You claimed, essentially, that you did not understand my post. Well, what exactly don’t you understand?
That doesn’t seem to be explicit, although I agree the argument could be interpreted that way.
Sure it could. You need amplification. Also, if you look at CO2 versus temperature, there isn’t a clear correlation. There have been periods where CO2 has risen but temperature has not. (And yes, I know that it may be possible to explain these things away, but that would miss the point.)
Look at it this way: Suppose that you graphed CO2 levels against temperature in the 20th century, and there was a very clear pattern connecting the two lines: whenever CO2 went up, temperature went up a few months later. And suppose that you could do a simple physics calculation with a logarhythmic curve that predicts this same temperature increase without any feedback loops or models. Do you agree that these things would strengthen the AGW-CO2 hypothesis?
I wasn’t defining it precisely, as I don’t think a precise definition is necessary for my hypothetical to work. However, if you like, you can use the top of the range laid out in my quote from post #216: 4.5C
You can assume that the model was way off before it was tuned; was an excellent fit after it was tuned; and way off after CO2 was removed.
Well, originally I did not understand your post. When you explained that what you were trying to say was essentially what you had said in post #228, I said essentially, “Okay now I understand what you are saying but you are wrong as I explained in post #229”
Whatever.
First of all, the only sense in which it could be said that you need amplification for the case of CO2 is that you are including the positive feedbacks such as the water vapor feedback and the ice albedo feedback. Since these feedbacks operate essentially equally on all possible forcings (CO2, solar, volcanic) and they are well-grounded in theoretical understanding, I don’t see any particular problem with this.
What I was talking about being problematical was having to invoke a feedback…or mechanism (one can argue about whether the word “feedback” is even appropriate in this case)…that amplified one particular forcing (e.g., solar) much more than the others, particularly when there is very little theoretical understanding of what any such mechanism would be (with cosmic rays being the only real candidate that I know of…and it has problems).
Second, you are creating a strawman. The AGW theory does not claim that CO2 is the only important forcing. Rather, it claims that the various forcings have the best estimates that we have been able to obtain for them and that this shows that during the 20th century there was a transition between natural forcings being dominant and anthropogenic forcings, especially the forcing due to greenhouse gases, being dominant. You may call this “explain[ing] things away” but that is only because you don’t understand the theory that you are arguing against.
Contrast this to the hypothesis that solar forcing and/or cosmic rays and/or other natural forcings are dominant: This hypothesis seems to fail particularly in the last 30 years or so, precisely the time when the accepted theory says that anthropogenic forcings are becoming dominant.
Well, that is ridiculous as it amounts to supposing that the atmosphere is different, namely, much less complicated, than it is. Sure, it would be much simpler to confirm the AGW-CO2 hypthesis if CO2 were the only signficant forcing that had acted on the planet over the 20th century and if the atmosphere behaved so simply that there were no feedback loops (and presumably no internal variability) and no need to model the atmosphere.
Well, sorry but nature does not make life quite so easy for us. That does not make the AGW-CO2 hypothesis any less correct. It may make it harder to to confirm the hypothesis and determine the exact strength of the effect but that is just the way the world is. Modern science is challenging.
I’m a little confused. Earlier, you stated “Reading your posts doesn’t help that much.” Are you taking that back now?
Lol. You yourself backed down from your statement in post 229, which was at best a nonsequiturial nitpick.
The problem is that it adds a degree of uncertainty to the analysis.
Here’s a nice quote on the subject:
http://www.climate-skeptic.com/
I would imagine that the solar irradiance theory does not claim that solar irradiance is the only important forcing.
Sure it does. Why do you think the IPCC talks about “90%” and gives ranges and error bars for climate sensitivity? At least in part, it’s because there is some uncertainty. Because climate is complex. Duh.
I hope it’s not improper to top this thread so I don’t have to go hunting for it tomorrow.
My responses will be forthcoming, but in the meantime, I noticed that brazil84 has not yet posted what he thinks of the quotes I posted from the IPCC. I am eager to hear what you think.
I picked one selection of yours from the IPCC and it did not stand up to scrutiny. At this time, that’s about all the attention I care to give to a poster who admits that he dodges and weaves intentionally.
I’m not sure topping this thread is kosher since apparently the other global warming thread I was posting on was recently locked for lack of resolution.
Which one?
The whole premise of this thread was that you agreed in an “Economic Hockey Stick” thread that you would consider the evidence for anthropogenic global warming. I posted, in my own words, the best evidence and then we spent the next several posts wrangling about whether the IPCC report states what I stated. After posting the actual quotes from the IPCC report, you agreed that you had not read these when you first posted on this thread.
And now, without even a specific reference to which passage supposedly did not stand up to scrutiny, or what scrutiny was applied, you categorically dismiss all the evidence and claim I admit to weaving and dodging.
EDIT: On returning to page 9, I see where the “weaving and dodging” quote comes from. I was referring to your assertion that the IPCC did not state what I stated, not that I was weaving and dodging my position. My goal is to hook you up with the data, and when you claim the data doesn’t exist, my weaving and dodging is simply to illustrate the lack of simple effort on your part.
Alright, I’ve caught up all the way to post #244, my 1/15 post. I’m breaking this down into responses to brazil84 and responses to ianzin, since the threads seem to diverge.
What I am claiming is the same as I’ve been claiming since post #1. If you didn’t read it, or understand it, the first time around, I don’t see a point in reposting it over and over in simpler and simpler terms.
The simplest way for you to find out is to read.
Edited out a long response: jshore beat me to it, but I’d still like to point out that the short-and-sweet explanation was linked in the caption for http://www.grida.no/climate/ipcc_tar/wg1/figspm-4.htm.
I think the crux of the problem here is your impression that the natural forcings cause a large rising and a dramatic shift in 1950 to strong cooling.
The figures show a temperature anomaly that would have been around +0.2 to +0.3 in 1860, sliding up to +0.25 to +0.35 in 1950, and then turning around to +0.15 to +0.25.
There’s no reason for the inflection point because there’s no inflection point.
(Edit: damn it, beaten by scr4)
Correction: The IPCC has admitted that a lot of past models have fudge factors, and some of the present ones, but the trend is moving away.
If these fudge factors make an appreciable difference, what you should see are large differences between the Third and Fourth Assessment Reports.
A bold statement for someone who 30 posts ago admitted he hadn’t read any of the key statements by the IPCC before denying that scientific evidence exists on global warming.
Have you no shame?
Perhaps, but you’d probably be surprised at how anti-do-something I am given how pro-humans-did-it I am. I posted a more complete explanation somewhere around post #160, in late December. Given a choice between “do something” and “do nothing”, I would probably fall on the “do nothing” side. However, I neither jump to that conclusion nor do I take the evidence lightly.
No, I think I meant to say exactly what I did - it’s an explicit reference to the process jshore linked on around post #170. Given what we know about how much infrared radiation CO[sub]2[/sub] absorbs, we can calculate how much extra energy is being added to the atmosphere. Putting in what we know in history, computers can add it all up and tell us what the temperature should be.
Now, you may legitimately disagree that we know all there is to know, but based on what we know, natural factors aren’t enough to explain the observed temperature.
RealClimate has an article about this that explains it in more detail, but the bottom line is that scientists never made those forecasts.
Actually, one just came out today.
This is the one I originally had in mind, though.
(Edit: jshore ends up linking this article later in the thread, sorry)
For non-scientists, scientific consensus really is all there is to go on.
Let’s say that I tell you that the mechanism of ozonolysis proceeds through a molozonide intermediate, followed by a [3+2] cycloreversion and [3+2] dipolar addition. Do you believe me? Would you believe me if another organic chemist felt the same way I did? What if 998 felt the same way I did and 1 disagreed?
Scientific consensus doesn’t mean that 50.1% of scientists voted one way and the other 49.9% have to accept it. It means that so many scientists believe one thing that it’s essentially useless to debate the subject further unless radically new evidence comes up.
We know more than they did in the 1970’s. The predictions they made were not possible in the 1970’s, but possible now.
The key piece of evidence, and the one that really sparked global warming research, was the Vostok Ice Core, pulled in 1986 (and, by some accounts, not properly analyzed until 1990). For the first time, scientists found that (1) CO[sub]2[/sub] and temperatures were definitely linked, and (2) we could find out a lot about our past by digging into rock/ice/trees.
I agree with this statement, BUT …
… you need to recognize that the sides on this debate are not equal. That is, there are intelligent and well-informed people on both sides of the debate, but the overwhelming majority of intelligent and well-informed people are on one side.
Now, you, as a non-scientist (I assume) have two options. One is to become an expert - get a degree in a climate-related science and demonstrate expertise, at which point you’re free to make whatever claims you like. The other, of course, is to accept that the vast majority of scientists are more likely right than wrong.
The short answer is that I don’t know, but there’s a more fundamental problem with the IPCC - the members are politically nominated. That is, they’re nominated by the political governments of their respective countries. Politicians in that country can send cherry-picked scientists.
It would be much better if, say, we had a panel of scientists nominated by scientists themselves - and we do. It’s called the National Academy of Sciences, and nomination represents one of the U.S.'s top honors for scientists. The NAS was created in the 1860’s, 30 years before anyone ever proposed global warming and before industrialization was rampant. They’ve existed by nominating their own members, and periodically are asked by Congress to investigate scientific matters and write up reports.
Do you trust this body of scientists? If so, would you accept any conclusions they give about the IPCC’s activities?
Attribution. Duh.
Lol. You explicitly admitted to “dodging and weaving intentionally.” Your claimed excuse was to “emphasize” that my question was supposedly “answered”
And here’s your new excuse:
:rolleyes: