[JohnB]

Essay.

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You're right, "this makes no sense," but I don't know enough to explain all that is wrong with the scenario in your post. I do know you are wrong about saying how I'm "arguing that a short drop... gives a greater reduction in TSI than a prolonged drop." That is your post (#274)--filled with your assumptions and "if" phrases--supposedly analyzing the solar cycles, which then creates your "logical question;" so don't claim they are my words or logic. If you'd like to quote from my posts, and ask questions or make points about those, feel free.

Okay, and using your words, not mine.

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In that post from June, 2011 (and the posts above), I keep saying "between the LIA & MWP," whereas you keep saying "between the Maunder Minimum & Today;" but either way the graph backs up my numbers--if I'm reading it right--of about a half Watt change in average forcing from drifting solar activity (minimum difference) ...though (to be fair, it is) slightly over 1.0 Watt/m^2 if you look at the maximum difference (GRT 2005 -or- AJS 2006). However, the "average" [black line] of the various studies is still at about a half Watt difference; isn't it?

This comment concerns the change in baseline solar forcing going from the Grand Minima of the Maunder to the Grand Maxima of the 20th Century and is in line with the IPCC diagram 6.13. A change in the baseline Solar forcing of about a half a Watt.

Yet in an earlier thread you quote your professor as saying;

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"According to the reconstructions, the difference in solar irradiance from the MWP max to the LIA min is about 0.5 or 0.6 W/m2 (reading from the figure, there are several different estimates presented by IPCC).
By contrast the difference between the irradiance during the solar min in 1997 and the solar max in 2002-3 was about 0.1% or roughly 1.4 W/m2." ~Dr. Scott

So the change over a standard cycle is about 1.4 W/m-2.

Both of these statements cannot be true. Consider a standard cycle the number of sunspots will vary from around 150 at maximum down to about 20 at minimum, with a median figure of around 80. So it follows that when the sunspot numbers go from 20 to 80 there will be an increase of roughly .7 W/m-2 in TSI. Half the 1.4 W/M-2 of a full cycle change. With me? Now the Maunder had no sunspots at all for quite some time so the median figure for an 11 year cycle was actually zero. We left the Maunder and came into the 20th Century and the median for a cycle went from 0 to 80 sunspots. Still with me? Yet the argument is being made that this will result in an increase of only .5 W/M-2.

One statement is that a change from 20 to 80 spots over 5 years will give an increase of .7 W/M-2 while the other is saying that an increase from zero to 80 spots over 100 years will give a 30% smaller increase in TSI of .5 W/M-2. Now do you see the problem? When we are considering the difference in solar forcings between then and now we need to compare the baseline solar forcing which is the median figure of the cycle.

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And specifically: Your numbers come from either subtracting measurements from particular solar cycles that are centuries apart, or from within the same cycle (post #274) and then extrapolating that number out for some hundred years.

If I want to know the difference in TSI between 300 years ago and now, then I would have to compare cycles that are "centuries apart", would I not? I don't understand your objection. Belief or disbelief is not required. If you think I'm wrong then show where the flaw in the maths or the logic is. Disagreeing because you find something "hard to believe" is religion.

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It is not that the graph doesn't match the data (as you claim: "it misrepresents"), but that the graph correctly displays the "smoothed" data. How could you evaluate all those papers, and yet not see that?

Smoothing is a valid mathematical process for removing short term inconsistancies. However to reduce values of from between 3 to 10 W/M-2 to .5 W/M-2 with "smoothing" requires the use of one of these;



And I would think that Dr Hansen has his figures wrong. The IPCC says the increase is 2.4 W/M-2 since 1850 or so gave rise to the .8 degree temp increase and Dr Hansen is claiming a rise of 1/4 that size (.58 W/M-2) in 5 years that has had no temp increase at all? Something here does not add up.

[Essay]

JohnB, on 20 March 2012 - 12:25 AM, said:

[re: 2 quotes from Dr. Denning]
Both of these statements cannot be true.
....
If I want to know the difference in TSI between 300 years ago and now, then I would have to compare cycles that are "centuries apart", would I not? I don't understand your objection. Belief or disbelief is not required. If you think I'm wrong then show where the flaw in the maths or the logic is. Disagreeing because you find something "hard to believe" is religion.
....
Something here does not add up.

John, there you go again; setting up some scenario of how measurements should be interpreted and pointing to your consequent results as a way to show that the accepted science must be wrong... if one will buy your premise. But first....
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Also, as I said, it's fine to quote me; but please don't use the quotes out of context.
That snippet above, about my "belief," was from a different paragraph; so to be clear, I said:
"In general, I find it hard to believe the science is really as bad as you suggest."

My general faith in science (as being more valid than you suggest science is) has nothing to do with what we were "disagreeing" on--a specific point, about how you incorrectly (istm) analyze and compare solar forcings. Your method ("the maths or the logic") isn't what I find "hard to believe," as your post intimated; I was talking there about science in general.

"Specifically" your method ("the maths or the logic") is invalid because it ignores the smoothed averages, and is thus prone to gross misinterpretation based on short-term (weather) effects and inadvertent cherry-picking (or not using the more robust data)... and probably other reasons; but I'm no expert in statistical analysis, so if you ask maybe an expert will better explain the flaws in your method.
===

But about buying your premises....
You also close with another contrived (strawman) scenario and suggest, "Something here does not add up." You seem to be the only one who sees this. Does that give you a clue about where the difficulty may lie?

Again, I'd like to ask: "Can you think of good reasons why the authors of those papers used a different way to analyze their data?" I won't bold it this time, but maybe I should rephrase it to ask if you can you think of good reasons why you used a different way to analyze their data? Or you could ask why the author's method is considered a more valid way to analyze their data; I'm sure a statistician, or any actively working scientist on this forum, could explain it clearly and simply.
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But most importantly, you clearly say

JohnB, on 20 March 2012 - 12:25 AM, said:

"Both of these statements cannot be true."

I think it is clear you don't understand something (in addition to my "objection"). You make this specifically clear with the comments about "zero to 80 spots over 100 years" and how you compare that with a 5 year "sunspot" forcing.

Please, does anyone else see why "Both of these statements cannot be true."

Anyone who can see that would overturn a basic scientific method (istm), and should get some positive rep--to say the least--if they could justify it!

~

[questionposter]

This topic: the perfect model for global warming discussions in the real world.

[JohnB]

Okay, cut the sanctimonious attitude.

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John, there you go again; setting up some scenario of how measurements should be interpreted and pointing to your consequent results as a way to show that the accepted science must be wrong

I'll put this as politely as I can. If I want to know the difference between Solar forcing in the 1600s and the 2000s, please elucidate oh wise one how this is done without comparing the firures from time periods some centuries apart? I mean, if I want to know the difference in population for a region between 1600 and 2000 then I would use the population figures for the years in question and subtract one from the other. So far you've been arguing that this method is invalid. So I really, really want to know what the valid methodology is.

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"Specifically" your method ("the maths or the logic") is invalid because it ignores the smoothed averages, and is thus prone to gross misinterpretation based on short-term (weather) effects and inadvertent cherry-picking (or not using the more robust data)... and probably other reasons; but I'm no expert in statistical analysis, so if you ask maybe an expert will better explain the flaws in your method.

Short term weather effects? The Maunder was 100 years long. I think that you are missing the main point here. I'm simply comparing what is actually written in the published papers with what the IPCC says is written in them. What do the papers say the change in solar forcing was between 1700 and 2000? I'm demonstrating a discrepancy that requires a much better explanation than "smoothing".

The various papers use sunspots as a proxy indicator for TSI. During a prolonged minima like the Maunder the number of sunspots dropped to zero thus giving a flatline effect to the reconstructions as it is impossible to model negative sunspot numbers. This flatline is clearly shown in Lean et al that I referenced before, in Figure 2. Personally I would think that the figure would go lower rather than flatlining but let's keep to what the published papers say. So Lean et al shows the TSI with a value of 1364 W/M-2 in around 1700 and a value of 1367-1368 for the year 2000. Your argument is that this 3 W/M-2 is really only .5 W/M-2 once you "smooth" it. Just out of curiousity, are you using a 500 year running average to do so? To get rid of those pesky "short term" weather effects?

Similarly Hoyt and Schattern show the TSI value changing from 1367 W/M-2 in 1700 to 1373 for the year 2000. Figure 9 as referenced before. So a 6 W/M-2 difference becomes .5 W/M-2 with "smoothing"? I knew an accountant once who thought that way. His income was $600,000 PA but after "smoothing" it was only $50,000. I think he gets released in three years or so.

But why is all this important? Very simple. We know that since 1850 or so the average temps of the planet have gone up. It has risen in a way as to suggest most strongly a change in forcings to the climate system of around 2.4 W/M-2. If we think of climate as a long equation to which we know the answer is 2.4 you'll see what I mean. All forcings and feedbacks must total up to 2.4 W/M-2 to describe the current climate system. If the Sun has only contributed .5 W/M-2 then there must be other large forcings and positive feedbacks to bring the total up to 2.4 W/M-2. However, if the reconstructions are correct and the change in TSI is more than 3 W/M-2 then it follows that even though the increase in CO2 must be also a warming forcing, since the nett change is 2.4 W/M-2 then there must be strong negative feedbacks in the climate system.

And a final point on this "smoothing". Exactly how does smoothing a tree ring based temperature series give you a Total Solar Irradiance figure? Does it work with other things? If I smooth the figures for the average height of an American can I work out how many cars he owns?

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I think it is clear you don't understand something (in addition to my "objection"). You make this specifically clear with the comments about "zero to 80 spots over 100 years" and how you compare that with a 5 year "sunspot" forcing.

Please, does anyone else see why "Both of these statements cannot be true."

Anyone who can see that would overturn a basic scientific method (istm), and should get some positive rep--to say the least--if they could justify it!

I'm not overturning a basic scientific method, I'm simply using it. The same method as is used in the various papers I've been quoting. Maybe I haven't been clear so I'll try again.

TSI varies within a solar cycle. Yes?
This variance is about 1.4 W/M-2 from cycle maximum to cycle minimum. Yes?
Therefore it varies about .7 W/M-2 each side of the average. Yes?
So using rough figures of 20, 80 and 150 sunspots for a cycle, when the number of spots drops from 80 to 20 then the TSI drops by about .7 W/M-2. Yes?
Conversely when the number of spots increases from 20 (minima) to 80 (average) then the TSI will rise by about .7W/M-2. Yes?

The above 5 points must be true if we are able to say that a typical sunspot cycle has a variance of 1.4 W/M-2 over the 11 year period.

Now let's consider the averages.

Up to about 1720 or so was the Maunder where there were no sunspots for about 100 years. Yes?
Therefore the average number of spots in a cycle was zero. Yes?
250 years later in the 20th C the average number of sunspots in a cycle was 80. Yes?
According to the IPCC the change in TSI for this period was .5 W/M-2. Yes?
Therefore increasing the average number of sunspots in a cycle from zero to 80 results in an increase in TSI of .5 W/M-2. Yes?

Now do you see the problem?

Increase the number of spots in a cycle from 20 to 80 gives a TSI increase of .7 W/M-2 but increasing the average from zero to 80 only gives an increase of .5 W/M-2. As the change in spot numbers is 1/3 larger for the average than for movement within a cycle it stands to reason that the change in TSI should also be larger.

The only assumption that I'm making is that TSI is related to sunspot numbers, which is exactly what the TSI reconstructions are saying, every single one of them. I'm not doubting the methodology or the "science", I'm using it. All it demonstrates though is that the figure of .5 W/M-2 is really rather untenable and should be revised upwards. I think that a fair approximation would be based on the average cycle and so a new figure of about .8 W/M-2 would be better.

[Essay]

Iggy, on 7 March 2012 - 01:36 PM, said:

Does anyone know what the elimination half-life is for anthropogenic atmospheric carbon dioxide? In other words, if we suddenly stopped adding CO2 to the atmosphere, how quickly would the levels drop toward pre-industrial levels?

I would think somebody has published that and it would be interesting to know.

If not, does anyone know what percent of anthropogenic CO2 is sequestered? That would give enough information to estimate in the same way that a drug's terminal elimination half-life can be estimated from knowing how much the kidneys eliminate.

Good question! This hones in on the crux of the biscuit... so to speak.

The "half-life" of CO2 in the atmosphere isn't some chemical property of CO2, but rather it is a consequent (or secondary) property of the biogeochemosphere.

Soil (a highly evolved creature that only recently came to predominate the biosphere and more strongly affect climate) is the 3rd largest pool of carbon on the planet. Trillions of tons of carbon are sequestered in soils. Yearly, the planet's soils and plants respire over a 100 gigatons of CO2.

...And we wonder why we can't account for 2 gigatons of emissions that seem to get sequestered each year!

[fyi: we emit about 8 GtC, and about half is sequestered--but only about 2 GtC of that is accounted for]
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A few decades ago I heard CO2 lasted for a few decades or up to a century, but these days I hear numbers for the minimum "half life" for CO2 as at least 120 years and up to several centuries.

Warming and higher CO2 levels may stimulate more plant growth on average to suck down more CO2, but those factors also stimulate soil respiration to release more CO2.
Warming Arctic soils release more carbon, but more rain could help other soils sequester more carbon. Drought or a flood-n-drought cycle (which even may average out to "more rain") causes the release of carbon from soils.
Deforestation is associated with a large release of carbon. Subsequent erosion can release even more carbon; whereas if the denuded landscape reverts to grassland, it can hold more carbon than the former forest!

Algal blooms in the Arctic, or along coastal population centers, may offset the carbon lost due to soils eroding into those waters.
Our excessive Nitrogen (fertilizer) inputs, which exceed by four times (4x) the carrying capacity of the biosphere to metabolize them, are sequestering a lot of carbon as it creates the dead zones throughout our fisheries. Those areas will become future oil shales for the planet!
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There's lots of ways CO2 gets bio-sequestered and bio-released. It seems to me that the potential exists to manage soils so that natural soil-based respiration is shifted by 1-2% in favor of sequestering more carbon.
I've read it takes 500 years to grow an inch of topsoil; but I bet if we worked on that intentionally, we could get it down to just a few decades... to grow an inch of topsoil. That, if done widely enough, would offset our carbon emissions.

Solar-powered, reductive pyrolysis allows for the production of bio-oils for fuel (along with the biosequestration of stable soil-enriching carbon to help grow more soil) from waste biomass. There are ways forward into a well-managed, sustainable future. We can change the "half life" of CO2 by how we manage the ecosystem, if we would choose to do so intentionally instead of unintentionally as we have been doing for centuries now.

[Iggy]

Essay, on 21 February 2012 - 06:07 AM, said:

These do not change the impact of long-term, relatively permanent forcers such as CO2.

Essay, on 30 March 2012 - 08:18 AM, said:

Iggy, on 7 March 2012 - 01:36 PM, said:

Does anyone know what the elimination half-life is...

A few decades ago I heard CO2 lasted for a few decades or up to a century, but these days I hear numbers for the minimum "half life" for CO2 as at least 120 years and up to several centuries.

Wow, that really is long term and relatively permanent.

That surprises me -- and worries me!

[questionposter]

Iggy, on 1 April 2012 - 02:24 AM, said:

Wow, that really is long term and relatively permanent.

That surprises me -- and worries me!

CO2 technically isn't permanent, it's just that human beings will either be extinct, on a different planet or a different species by the time the effects wear off.