Who here is a global warming skeptic?

[swansont]

Political ramifications do not alter the science in any way. It's Argument From Adverse Consequences/Appeal To Fear/Scare Tactics, i.e. a logical fallacy.

[mooeypoo]

!

Moderator Note

This is a mainstream science sub-forum, please avoid politics.

There is a (probably more than one) topic about global warming in the politics forum dealing with the political aspect of it. Keep political issues there.

[Essay]

Wow! There is so much to address in your posts, and it sounds genuine, but it's just too overwhelming. Maybe later each misconception can become a topic itself, in the proper sub-forum, but until that day....

 

The whole 'Gaia' movement which regards humanity as a toxic parasite on the Sacred Mother Earth

...of destroying the carbon economy and building the infrastructure for a green economy to replace it (the suburbs, for example, where more than half the population now lives, have got to go) is going to be imposed exclusive on the poor and the lower middle class

...soaks up all our resources.

 

It is the transition to a new economy that builds wealth. Where do you think the wealth came from to build our existing economy? It's not as if the wealth existed to begin with....

 

But about the future, it is specifically so that future generations can continue to enjoy a vibrant economy, and continue to pursue cures to diseases and social problems, and continue to benefit from the pursuit of knowledge, that people are currently concerned with the sustainability of our civilization and its resources and life-support systems.

 

It's not really about the climate, but about how climate affects the biodiversity that supports the ecosystem services that provide us with properity.

But that means it is neccessarily, in the end, about the climate.

===

 

But where did that "parasites on Gaia" notion come from? We are a part of the whole system, described metaphorically as Gaia, and should not be seen as separate from Gaia. As E. O. Wilson suggests, we need to realize that we cannot "transcend nature," but only aspire and strive to be One with nature, or to be as good and effective as nature, or to understand and embrace nature, mutualistically building resilience and supporting evolution.

 

Get rid of the suburbs? We don't "got to" get rid of the suburbs, though I know that is a conclusion jumped to by some. All of your suggestions about what we need to be "destroying" in order to save the future are speculative and should not influence your judgement of the science behind the greenhouse effect and how it affects climate.

===

 

Gosh what a torrent of caveats that you see, but rather than address each....

Skepticism about a problem shouldn't be based on fear of suggested solutions, but that seems to by your justification for doubting the problem. A perspective beyond one's own lifetime can be helpful to focusing on the problem, rather than focusing on fearing the implied consequences.

 

So can we look at influences affecting climate over multiple generations versus shorter-term influences?

...just to focus more on the problem?

===

 

 

On average we exchange several hundred watts/sq.meter over the surface of the globe; but a few extra watts per square meter, in the right place for enough average duration, can make a big difference to the climate.

 

QUESTION:

How many watts difference does it take to send us into an ice age, or to swing us back out of an ice age?

Well, it's a trick question, because there isn't any difference in total energy between an ice age and interglacial period; it's just distibuted differently, as described by the Milankovitch cycle, which then affects feedbacks and so ice ages come and go.

 

Differences of from 3 to 6 watts/sq.m in the distribution of heat (especially insolation at 60 deg.N.) controls the ice ages via feedbacks. We are now adding close to that amount of heat to the whole system (24/7/365), changing the baseline on which the feedbacks developed and then operate.

===

 

Now consider....

A difference of about a third of one (0.3) watt/sq.meter describes the variability in forcing by solar output between the medieval warm period (MWP) and the little ice age (LIA), but that was ongoing for decades and so was very noticeable.

 

Compared with....

Insolation varies almost 3 watts/sq.meter during the sun's 11-year sunspot cycle, but that averages out to become part of the baseline on which the feedbacks have always operated and so is not very noticeable. What do you think would happen if the sunspot cycle was stuck on maximum for a few centuries?

 

We are now adding a similar forcing, which is an order of magnitude greater than the difference between the MWP and LIA forcing, to our climate system--for what will be a longer duration. To believe that the system will continue operating as before, with what some describe as simple "variability," takes a lot of faith. Of that judgement, I'm very skeptical.

 

~

[JohnB]

A difference of about a third of one (0.3) watt/sq.meter describes the variability in forcing by solar output between the medieval warm period (MWP) and the little ice age (LIA),

 

Essay, how do you arrive at that figure? The difference between the LIA and today is listed by the IPCC as 2.4 w/sq.metre. Assuming the MWP was of similar temp ranges as today one would expect the forcing value to be similar.

 

Edit. Thanks mississippichem. The idea that "all scientists in the 70s were warning of cooling" or that there was a consensus is a myth. However it is also wrong to say that "no" scientists were warning of cooling too. The simple truth is that "some" scientists in the 1970s were warning of cooling and their views were publicised by Newsweek etc.

 

 

Note that those interviewed for the "In Search of..." program were quite certain that an Ice Age was coming. So it is quite true that some scientists were warning of cooling.

Edited June 24, 2011 by JohnB

[swansont]

The idea that "all scientists in the 70s were warning of cooling" or that there was a consensus is a myth. However it is also wrong to say that "no" scientists were warning of cooling too. The simple truth is that "some" scientists in the 1970s were warning of cooling and their views were publicised by Newsweek etc.

 

It would be wrong to say that no scientists were publishing articles on cooling. But that wasn't claimed in my rebuttal.

[JohnB]

Fair enough. The words you used were "in a panic" and I doubt anybody was. I should read more carefully.

 

In my defence I can only say that I've noticed that usually when this comes up on the net the camps divide along the lines of;

 

1. "Scientists were warning about cooling in the 70s" and

2. "No they weren't, it was a media thing."

 

My point was that the truth lies between these two extremes. (Where it is usually found. )

[Essay]

It would be wrong to say that no scientists were publishing articles on cooling. But that wasn't claimed in my rebuttal.

 

Plus, the discussions back in those days make more sense when viewed from the perspective of a hot new revelation, the newly confirmed Milankovitch Cycle....

 

"At a conference on climate change held in Boulder, Colorado in 1965, evidence supporting Milankovitch cycles triggered speculation on how the calculated small changes in sunlight might somehow trigger ice ages. In 1966 Cesare Emiliani predicted that "a new glaciation will begin within a few thousand years." In his 1968 book The Population Bomb, Paul R. Ehrlich wrote "The greenhouse effect is being enhanced now by the greatly increased level of carbon dioxide... [this] is being countered by low-level clouds generated by contrails, dust, and other contaminants... At the moment we cannot predict what the overall climatic results will be of our using the atmosphere as a garbage dump." ~from wikipedia's page on global cooling.

 

http://geography.abo...ilankovitch.htm

"Though he did his work in the first half of the 20th century, Milankovich's results weren't proven until the 1970s.

A 1976 study, published in the journal Science* examined deep-sea sediment cores and found that Milankovich's theory corresponded to periods of climate change. Indeed, ice ages had occurred when the earth was going through different stages of orbital variation."

[* Hays, J.D. John Imbrie, and N.J. Shackleton. "Variations in the Earth's Orbit: Pacemaker of the Ice Ages." Science. Volume 194, Number 4270 (1976). 1121-1132.]

 

Essay, how do you arrive at that figure? The difference between the LIA and today is listed by the IPCC as 2.4 w/sq.metre. Assuming the MWP was of similar temp ranges as today one would expect the forcing value to be similar.

 

Yes, but that large difference between the LIA and now is not due to solar forcing. It is mostly attributed to CO2, as a "new forcer" in the system. My numbers came from notes on a climate science course, in a class about radiative forcing, but the lecture used these IPCC sources.

I'm not sure how the "3 Wm-2" figure came into in my notes.

 

Here is a clarification from my professor today:

"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... it's only a quarter of an order of magnitude, by these figures.

But the point remains that several generations, or a century or more, of a small change will move climate from MWP to LIA conditions; whereas larger, but shorter (decade-scale) changes aren't easily noticed within one's lifetime. It's easy to point to past variability when speculating about the effect of the large change we have put into the climate system, but we can't yet conceive of how that will play out on a multi-generational or century scale for civilization.

===

 

http://www.ipcc.ch/p...h6s6-6-3-4.html

 

"Various simulations of NH (mean land and marine) surface temperatures produced by a range of climate models, and the forcings that were used to drive them, are shown in Figure 6.13. Despite differences in the detail and implementation of the different forcing histories, there is generally good qualitative agreement between the simulations regarding the major features: warmth during much of the 12th through 14th centuries, with lower temperatures being sustained during the 17th, mid 15th and early 19th centuries, and the subsequent sharp rise to unprecedented levels of warmth at the end of the 20th century."

...

 

"...different reconstructions of solar irradiance (Bard et al., 2000; Y.M. Wang et al., 2005) to compare the influence of large versus small changes in the long-term strength of solar irradiance over the last 1 kyr (Figure 6.14b)."

 

 

http://www.ipcc.ch/p...igure-6-13.html

===

 

As I said, I'm skeptical that this large, constant, long-term, "new forcer" in the climate system will manifest itself as (what we have come to think of during the past several millennia as) "normal variability."

 

~

[Marat]

I agree that the political and economic aspects of the global warming debate should generally be treated as issues separate from the scientific questions. However, I do think they are relevant to the science in that the potentially dire effects on the economy required to address carbon emissions inform the degree of skepticism with which the scientific claims for global warming must be addressed. If fixing the global warming problem required only $1.98 additional tax per head in the developed world, then it would be worth doing just on the odd chance that the global warming panic was justified.

[JohnB]

Essay sorry, perhaps I'm being dense or simply not quite getting what you are meaning.

 

As I understand it, the cause of the forcing is irrelevent, it's the value that matters.

 

What you appear to be saying is that a .3 W/M-2 solar forcing produces roughly the same temp change as a 2.4 W/M-2 predominantly from CO2. This implies that CO2 forcings are "special" in some way.

 

Similarly the length of time that the forcing is in effect is simply not relevent. If all other things were constant a .3 W/M-2 forcing will give a certain value of equilibeium temp change regardless of the length of time it takes the forcing to change. Whether the forcing takes 1 year or 100 years to reach the new increased value, the temp rise will be the same, only the rate of change of temps will be effected.

 

I'm afraid your professors clarification doesn't help me in this either. We still finish up with a .5 W/M-2 forcing having the same (temp change) result as a 2.4 W/M-2 forcing. The maths doesn't work that way. Temp changes are directly related to the change in forcing value. Similarly due to the systems lag the 1.4 W/M-2 variability over the course of a solar cycle makes no difference, a better idea of the general solar forcing comes from the average value for each cycle.

 

As a side note, what scientific specialty is not represented IPCC WG1 Chapter 6? (A rather surprising omission given the discussion is climate over the last 2,000 years.)

 

PS. "Damn you!" While I've dug pretty deeply into dendro etc, reconstructions I've avoided the SI ones. You've just added a lot more to my reading list. Blast.

[Essay]

...potentially dire effects... inform the degree of skepticism with which the scientific claims ...must be addressed.

Really!?

 

Marat, the full post sounds compelling; but you are still judging the validity of the problem (the science) based upon how you feel about various suggested (the social policy) solutions.

 

Shouldn't the degree of skepticism about a science be based upon the levels of authority, consensus, and breadth & depth of supporting evidence informing that science?

~

 

***End of post #1***

 

 

***Begin post #2***

 

Thanks....

As I understand it, the cause of the forcing is irrelevent, it's the value that matters.

~~Yes, I'd agree with that.

===

 

What you appear to be saying is that a .3 W/M-2 solar forcing produces roughly the same temp change as a 2.4 W/M-2 predominantly from CO2. This implies that CO2 forcings are "special" in some way.

~No, that isn't what I was trying to say. First, I used the wrong numbers by half. It should have been a 0.6 W/m-2 for the forcing difference between the MWP & LIA, which is what the prof's email clarified (along with correcting 1.4 W/m-2 for the sunspot cycle, instead of 3 W/m-2).

 

~Neither was I trying to point at CO2 as special forcer in any way. I often try to point out that CO2 adds watts-per-square-meter, 24 hours/day, 365 days/year, unceasingly year after year, and it is more evenly distributed than solar insolation; but I think that is accounted for in determining its forcing value.

===

 

Similarly the length of time that the forcing is in effect is simply not relevent.

~Huh? I don't agree with what you've written, but you imho must think it's true relative to some perspective that you've left unspecified. You must imho also mean "for a forcing to impart its full effect on the system," because a 10 Watt forcing over one day would not change things as much as a 10 Watt forcing over one century. The duration of the forcing does matter; both to fully effecting its change on the equilibrium heat exchange, and to maintaining that new equilibrium so long as the forcer is in effect.

===

 

If all other things were constant a .3 W/M-2 forcing will give a certain value of equilibeium temp change regardless of the length of time it takes the forcing to change. Whether the forcing takes 1 year or 100 years to reach the new increased value, the temp rise will be the same, only the rate of change of temps will be effected.

~Yes, this is closer to what I was getting at. I was trying to point out that a relatively small change in forcing, of 0.6 W/m-2 over 400 years, changed climate from MWP conditions into LIA conditions.

 

~~The solar cycle was just included for contrast, showing how a larger forcing--over a short period--has little effect; as the influence of volcanoes also shows.

===

 

I'm afraid your professors clarification doesn't help me in this either.

~He was just correcting my numbers, as mentioned above. I'm sure he said 0.6 W/m-2 in his lecture, but I wrote down "+/- 0.3 W/m-2" in my notes to indicate the 0.6 Watt range. I didn't adjust for that when I first posted above.

===

 

We still finish up with a .5 W/M-2 forcing having the same (temp change) result as a 2.4 W/M-2 forcing.

~We still finish up with a 0.6 W/m-2 forcing having the same (temp change) result as a 2.4 W/m-2 forcing has had so far!

 

~~That is the point! We only have seen the preliminary effects of GHG forcing, so far. Our relatively large forcing has only just begun to impart its full effect on the climate (heat exchange system), and it will be ongoing for centuries to come. If a small forcing can change climate that much over several centuries, then what should we expect for the future--from a larger forcing--over several centuries and even millennia?

===

 

The maths doesn't work that way. Temp changes are directly related to the change in forcing value.

~Right, the math doesn't work that way, because 400 years of forcing shouldn't be "directly related to" the past few decades of forcing.

 

~~But...

Temperature changes are indirectly related to the change in the forcing value through a system of enhancing and attenuating feedback mechanisms.

Average air temperature is just one manifestation of how the planet's heat exchange system expresses itself. Ice and ocean currents absorb the bulk of the forcings, and it is these that establish the baseline climate; hence the worry about tipping points.

===

 

As a side note, what scientific specialty is not represented IPCC WG1 Chapter 6? (A rather surprising omission given the discussion is climate over the last 2,000 years.)

~Anthropology??

 

PS. "Damn you!" While I've dug pretty deeply into dendro etc, reconstructions I've avoided the SI ones. You've just added a lot more to my reading list. Blast

~Points and laughs....

~~

===

 

This longer-term perspective makes the descriptions of vinyards in England, etc., more understandable. MWP conditions allowed people to farm in Greenland, but that doesn't mean it was warmer than the current climate. It only means the MWP climate had been nearly as warm, but for a century or more--long enough for the edges of the ice, populations, and agriculture to adjust.

 

So what I was trying to say was that: When the current forcing fully manifests its effects in our planet's heat exchange system, we should expect to see --after a few centuries-- changes that are 4 to 6 times as great as the difference between the LIA and MWP, if the effects are proportional to the forcing.

 

~

Edited June 26, 2011 by Essay

[Marat]

If global warming were just an academic problem, then yes, I would agree that we should just evaluate it scientifically, and adjust the degree of skepticism appropriate to the issue according to the nature of the scientific data. But in this case it is also a social issue, so the social cost has to inform our criteria of conviction.

[JohnB]

~Points and laughs....

"They laughed at Galileo, they laughed at Einstein, but I still worry when they laugh at me."

 

Thanks for the reply.

 

To clarify what I meant on the "length of time the forcing is in effect". If the Sun jumped by 2 W/M-2 tomorrow (and stayed at the new value) there would be a change in the equilibrium temperature. Not immediately due to lag but the temp would rise. The rise in equilibrium temps would be the same if the Sun increased insolation by 2 W/M-2 over the next 50 years. That was what I meant. The change in equilibrium temp is the same for a given change in forcing regardless of whether the change in forcing is over 1 day or 100 years. Which is what you said. so we mean the same thing, but I phrased it poorly. Sorry.

 

The .6 W/M-2 is pretty much in line with the IPCC graph you posted before. .5 or .6 W/M-2 the difference is rather light. However I do see a bit of a problem. (Which may resolve itself with more reading.) The IPCC graph uses as one of it's forcing papers Bauer et al 2003. (B..2003-10Be and B..2003-14C in the graph.) I have trouble matching that with Figure 1A which clearly shows the SI at 1368 W/M-2 up from a baseline of 1365 W/M-2. Similarly in 1700 the Solar figure goes down to 1362 W/M-2. This is a range of 6 W/M-2, not .6 W/M-2. The figure in the published paper is definitely not the one shown in the IPCC graph. I wonder why? (Not being narky, I really do wonder)

 

My concern with this type of paper, and I'm not casting aspertions on anybody, are the assumptions and statements involved. Baeur et al use Jones et al 1998 and Mann et al 1999 for comparison. Leaving aside the statistical and proxy choice problems of Mann et al 1999 we still have Section3.1 saying;

The CLIMBER-2 simulations yield the highest correlations with respect to M99 data

 

I have to object to this. M99 (Mann et al 1999) is not data, it is a statistical reconstruction. You'll note the section is called "Correlations Between Model and Data" when an accurate description is "Correlations between models and models" a totally different thing altogether.

 

Similarly Section 2.2 states;

Globally, forest cover was reduced from 1000 to1992 by30% from 57 to 41.5 106 km2.

 

Am I being picky by asking how the hell they arrived at that number? Okay, they got them from the CLIMBER-2 model runs used in Brovkin et al 1999.

 

Brovkin also seems to suffer from the same problem that Baeur does;

During the years around 1800, the model predicts a cooling (in accordance with a minimum in solar irradiance), and observations show a warming. Therefore, the other climate forcings could be responsible for the warming during this period.

 

They are not "observations" they are a reconstruction. This make the logical "Therefore" moot, as the possibility of the reconstruction being wrong at that point is not considered.

 

I note in passing that the models are deemed correct because they roughly match the reconstructions and quite often the reconstructions are deemed correct because they match the models. This strikes me as a very circular reasoning.

 

One of the things I'm sceptical about (it's past midnight but I'll try to be clear) is not so much the models themselves, but the confidence placed in them. I've only had a few hours to read but the papers listed above give a good example. Bauer uses as input for her model the output of Bovkins model. Brovkin in turn uses other models as inputs for his model. Brovkin also uses 2.6 degrees pegged as the sensitivity for his model. So we have models feeding models feeding models and the results are checked against statistical reconstructions. Such a process doesn't give one great faith in the accuracy of the outcome. For example if Bovkin was wrong and the sensitivity is 1.4 degrees then his model is out and all the ones based on his output are also out.

 

More at another time, but a final point.

 

The missing specialty is Archaeology. Dr. Mann recently released a new paper on sea level rise. I haven't read the full paper yet but I would be very surprised if anybody can infer Global rates of sea level rise from 2 points on the Carolina coastline. No archaeologists are Lead or Co-ordinating auhtors for the IPCC in paleoclimate. This strikes me as odd because if you want to know what the climate and sea levels were like for the last 2,000 years the obvious people to ask are the ones who excavate historic sites for a living and who read the written records of the times.

 

Ignoring the very real effects of isostatic rebound etc, sea level has gone up and down like a damn yoyo in places. cf this page on ancient salt production. We know what the sea level did relative to the land by when salt production started and stopped in various places. Note the old Roman port of Trajan, now some 3 metres above sea level and serving as an irrigation reservoir. Trajan was built because the original ports were flooded by rising seas.

 

There is a vast wealth of knowledge but reading Chapter 6 of WG1 it barely gets a mention. And not being mean, but I doubt an atmospheric physicist (meteorologist, whatever) is the best person to evaluate archaeological data.

Edited June 26, 2011 by JohnB

[Essay]

Thanks JohnB,

 

Oh, I see. You were talking about the rate of the forcing, not the rate of the response. That's the "perspective" that I didn't get. Thanks for the clarification!

 

It's an interesting thing to think about. Most forcers change slowly enough for the climate to adjust in tandem, or with little lag, and something instantaneous like a volcano usually is not large enough in magnitude to create more than a few years of lag until fully affecting the system. But a large forcer such as our CO2 injection, added over a geologically instantaneous moment, will take centuries to fully manifest its effects within the planet's heat exchange mechanism--the ice sheets, deep ocean, and our climate.

The deep-ocean conveyor takes about 1000 years to cycle once. Most of that unique climate "buffer" (unlike the ice sheets) doesn't even know the Industrial Age has happened yet; it has yet to be affected by the new GHG forcer. Thanks for the thoughts....

===

 

But in general I'd say:

Don't confuse facts with data. Data from different sources inherently come with different levels of skepticism, but....

Data are still data, whether they are from direct observations or from calculations...

...generated from reconstructions of observed proxies, or from models of observed processes.

 

And:

When a model meets a model....

If previous work is adjusted, then the subsequent work is not invalidated; but only needs to be readjusted accordingly also.

For example if Bovkin was wrong and the sensitivity is 1.4 degrees then his model is out and all the ones based on his output are also out.

Just completely out?

===

 

But aside from your skepticism of how the science is built upon previous work, I take it you see my point about the magnitude of the problem. I guess we could hope that, as you suggest, the climate sensitivity may only be 1.4 degrees; so then future generations can expect a change only 2 to 3 times as great as that between the LIA and the MWP.

 

Of course that is also assuming we keep our CO2 levels from increasing any higher.

===

 

 

But hey, JB! I expected a kudo for correctly guessing "Anthropology" as the missing science you asked about. It amazes me also that climate science hasn't sooner more closely examined the long human influence on climate change.

Have you heard of Wm. Ruddiman's work? ..."Plows, Plagues, and Petroleum"...?

 

http://cires.colorad...tures/ruddiman/

The anthropogenic era is generally thought to have begun 150 to 200 years ago, when the industrial revolution began producing CO2 and CH4 at rates sufficient to alter their compositions in the atmosphere. A different hypothesis is posed here: anthropogenic emissions of these gases first altered atmospheric concentrations thousands of years ago. This hypothesis is based on three arguments.

I found this especially compelling (like a 2x4 to the forhead), since I had already read "1491" by Mann, and "Larding the Lean Earth" by Stoll (and subsequently, "Vestal Fire" by Pyne).

 

Sea level doesn't interest me much, since it is only a response to climate; but I suppose as another way of checking models, it would be good to know more. What I find surprising for climatologists to have overlooked until recently is that:

Anthropology can tell us about our land-use changes and the effects on albedo, soil carbon and soil hydrology, and GHGs --by telling the story of how silva/agriculture, irrigation, soil and biomass management, and especially anthropogenic fire has reworked the biosphere several times over-- increasingly during the past few millennia.

===

 

~SA

 

p.s.

http://www.washingto...sweyerfire.html

Cycle of Fire is a suite of books that collectively narrate the story of how fire and humanity have interacted to shape the Earth.

...

Equally, the Cycle reveals humans as fire creatures, alternately dependent upon and threatened by their monopoly over combustion. Fire's possession began humanity's great dialogue with the Earth. Cycle of Fire tells, for the first time, that epic story.

 

~off to lunch

[JohnB]

I hope lunch was enjoyable.

 

Yes, I should have given kudos for Anthropology but it was well past midnight and I was damn near asleep. Please accept the kudos now.

 

The problem with Archaeology or Anthropology in this case is that most of the evidence that they can supply is qualative rather than quantative. For example we can know that the climate changed at the end of the Roman Warm Period and became much colder, but we can't tell how much colder in degrees. So if we are looking to quantify the differences, the records are of limited value except as a general check.

 

As an aside. That's what first interested me in the actual science. I saw the "Hockey Stick" and I knew from my readings in History that the NH climate didn't look like that. People forget that the word "school" derives from the ancient Greek word meaning "leisure". IOW, you have to be able to take time out from simply surviving to be able to have education. One of the reasons for the "Dark Ages" was simply that times were very hard indeed. When the warmth returned in the MWP, education flourished in many ways simply due to greater crop yields allowing more food and more leisure time. The reconstruction simply didn't match the observed facts of life during the period. (I've noticed some historians over at Judith Currys blog that feel the same way.)

 

I take your point re data, but I find that sometimes the reconstructed "data" is presented as "fact", and this concerns me. Not picking on Dr. Mann, but MBH 1998 by its iconic nature was pretty well presented as "fact" in the TAR, for example. As the old saying goes "You are entitled to your own opinion, but not your own facts".

 

There is nothing wrong with building on previous works, "shoulders of giants" and that sort of thing. However it is always worthwhile to go back to basics occasionally. Someone building on Bauer might not realise that large chunks are based on Brovkin and may not realise the assumptions Brovkin is based on. So an error can be perpetuated. I'm one of those picky people who tends to read the papers that papers are based on which means instead of reading one, I finish up reading 6 or 7. I think this approach is needed for the amateur trying to understand climate science. I need to understand not just what is said, but where it comes from as well. Which is a bugger because CS is barely a hobby for me and takes time out from important things like learning dead languages.

 

I have to disagree with the idea that forcings change slowly enough for the climate to respond in tandem. If we assume that Bauer et al 2003 was correct in the reconstruction of SI forcings. it's quite obvious from Figure 1a that SI forcings are quite large and fast. A rise of 2.5W/M-2 between 1050 and 1100, 2.5 W/M-2 from 1340 to 1370, a drop of over 4 W/M-2 from 1370 to 1450 and a rise of 3 W/M-2 from 1700 to 1750. The rate of change of these SI forcings makes the 2.4 W/M-2 from 1850 to present pale in comparison.

 

(And I'd still like to know why this diagram was misrepresented in IPCC graph. Maybe there is some maths that I haven't learnt yet where 1368-1365= .6, but i doubt it. ) I'll have to read the other SI papers to see a comparison.

 

I'm not a fan of the "Anthropocene" concept. It often seems to be pushed by people with an ideological barrow. They seem to have the idea that everything was rosy and nature was in "delicate balance" and "harmony" until those nasty humans came along and messed things up. Speaking anthropologically, mankind has never liked the idea of being at the mercy of anything, we like to think we can control things. 10,000 years ago this led to the "Nature" religions wher people believed they could influence the weather if they appeased the rain God. This took many forms, from personal mutilation to killing heretics to show the relevent god just how much we dislike people who don't worship the rain god. In the time of the LIA we'd moved from nature gods to the christian one. People believed that the very cold year of 1626 was caused by witches "cooking" the weather and 4,400 people were executed for "controlling" the weather.

 

This speech by Sallie Ballunis is quite clear and points out that even the reasons used for some of the trials are the same words as we hear today in the climate debate.

http://www.youtube.com/watch?v=8C1CKKhN7ng

 

I currently view the "Anthropocene" idea as one pushed by people who can't accept that mankind is a rather insignificant speck in a great, wonderful, amazing and rather hostile and uncaring Universe. The Anthropocene idea gives the impression that we have power over nature, rather than being at the mercy of nature. And nature has no mercy.

 

PS. I don't think I've read Ruddiman, although the name is familiar. I'll have a read of the books you say and see if I change my opinion.

Edited June 28, 2011 by JohnB

[Essay]

If global warming were just an academic problem, then yes, I would agree that we should just evaluate it scientifically, and adjust the degree of skepticism appropriate to the issue according to the nature of the scientific data. But in this case it is also a social issue, so the social cost has to inform our criteria of conviction.

If a meteor that was large enough, and was heading close enough to Earth for us to be uncertain (within the time needed to implement a solution) about whether it would hit or not, we would need to take action to be completely assured of being safe. The estimated costs of any suggested solutions doesn't change the problem.

Marat, I'll let somebody else try addressing this point going forward, but for now:

 

You can apply all the skepticism you want toward any suggested solutions for the global warming problem, due to the "social costs" that you perceive; but to "adjust the degree of skepticism" about the science itself, based on your perception of estimated, proposed costs, is not logical.

 

~SA

 

*__*

 

~~ Gotta run, but for now this might save some time....

 

...2.5W/M-2 between 1050 and 1100, 2.5 W/M-2 from 1340 to 1370, a drop of over 4 W/M-2 from 1370 to 1450 and a rise of 3 W/M-2 from 1700 to 1750. The rate of change of these SI forcings makes the 2.4 W/M-2 from 1850 to present pale in comparison.

 

(And I'd still like to know why this diagram was misrepresented in IPCC graph. Maybe there is some maths that I haven't learnt yet where 1368-1365= .6, but i doubt it. ) I'll have to read the other SI papers to see a comparison.

 

You might save yourself some reading if you consider that what you describe as forcings... "quite large and fast" are simply swings of the 11-year solar cycle. By looking at 50 year increments, you go from the beginning of one cycle forward to the middle of another cycle--between 44 and 55 years on. The numbers you are looking at, 2.5, 3, and 4 W/m-2, are typical of the 5 year change (or multiples thereof) in a solar-cycle. It was the change in the long-term solar constant, illustrated by that graph I posted, of a bit over half a Watt changing over 400 years --a slow change in forcing-- that gradually moved us from MWP conditions into LIA conditions.

 

~more later

[JohnB]

You might save yourself some reading if you consider that what you describe as forcings... "quite large and fast" are simply swings of the 11-year solar cycle. By looking at 50 year increments, you go from the beginning of one cycle forward to the middle of another cycle--between 44 and 55 years on. The numbers you are looking at, 2.5, 3, and 4 W/m-2, are typical of the 5 year change (or multiples thereof) in a solar-cycle. It was the change in the long-term solar constant, illustrated by that graph I posted, of a bit over half a Watt changing over 400 years --a slow change in forcing-- that gradually moved us from MWP conditions into LIA conditions.

 

Um, No.

 

Sorry but that doesn't work. By your own accounts and posting above, the amplitude of a solar cycle is 1.4W/M-2. You also say that baseline SI won't change quickly and only by about 1 W/M-2 over a long time period. The bottom line of this argument is that the SI rise cannot exceed 2.4W/M-2 and will only reach that after centuries of time. Increase in baseline from Maunder to now is 1W/M-2 plus the Schwabe cycle of 1.4W/M-2 = 2.4W/M-2. The figures you've quoted simply don't allow for more than that figure on a time scale of less than centuries.

 

The graph you posted does not illustrate the long term solar forcing. It shows the long term solar forcing that is used by the models. This means that it is an estimate and not a fact, unless the value can be shown to be correct. The graph doesn't demonstrate this. So what does it demonstrate?

 

The IPCC uses Bauer 2003 twice in the graph so I'll start there. (These two are referred to in the IPCC graph as B..2003-14C and B..2003-10Be.) Bauer et. al. 2003 is a reconstruction of SI over the last 1,000 years. They assume a relationship between C14, Be10 and SI so as to use C14 and Be10 as proxies for the SI. Figure 1a in the paper shows the results. According to the C14 proxy during the MWP the SI was about 1368 W/M-2 or 3 W/M-2 above median. This dropped as we went into the LIA with the SI going down to 1362 W/M-2 around 1700AD. (3W/M-2 below median) This then rose again in the instrumental period to the 1368 W/M-2 mark. This is a change of 6W/M-2.

 

The 10Be isn't as marked in variance but is still plus or minus 1 W/M-2 deviation from median.

 

This is the only SI reconstruction in the graph, all the rest are forcings used as inputs for modelling purposes as is made clear by the description. We must mind the difference between data and facts, musn't we?

 

Again looking at Figure 1a in Bauer, we see that the proxies don't have high resolution in the distant past but show the variations due to the standard solar cycle quite well in the recent past. The one and a bit variance is plainly visible in the post 1850 period.

 

The problem here is that what the graph shows is models that use a .5W/M-2 SI long term variation and a (roughly) 2.6 degree sensitivity to CO2 doubling produce similar curves. This is not a surprise. However it is not proof that the long term variation was in fact .5 W/M-2 for SI. The only paper represented in the graph that is an SI reconstruction places the value at more than 3 W/M-2. In fact I can expand on this a bit. Now that I've located and at least skimmed all the papers in the graph I can say that the graph demonstrates that climate models using the SI from Crowley 2000 and a CO2 sensitivity of about 2.8 degrees agree with each other.

 

One of the problems, or difficulties with paleoclimate is what do we calibrate the models against? The most obvious things are the paleo reconstructions. But which ones? Taking a simple comparison do we use MBH 1998, the "Hockey Stick" which shows a gradual decrease over 1,000 years and a sharp uptick or Moberg 2005 which has a rather more pronounced MWP and LIA? While they are said to be comparable, because they each fall within the others error bars, they are quite different at the 95% level.

 

If Centennial variations are small, then so are the natural forcings. (Talking pre industrial here) An extreme example for this opinion is Tett et al 2007 (TBC 2006 in the graph) Their view is: "These simulations suggest that since 1550, in the absence of anthropogenic forcings, climate would have warmed by about 0.1 K." Bollocks. Ask any historian or Archaeologist if the climate anywhere has been that stable for 450 years ever, the answer is "No". Sorry but his model is wrong. Be that as it may, an assumption of slow and small natural climate change requires natural forcing changes to be slow and small as well.

 

I've linked to Bauer to show that the SI reconstuction is for a 6 W/M-2 change in SI between the Maunder and now. Many of the papers reference Lean et al 1995.

I draw your attention to Figure 2 in that paper where the reconstruction shows a maximum of 1364 W/M-2 for STI during the Maunder rising to a (then) figure of 1368 W/M-2 a change of 4 W/M-2. Lean et al is also a reconstruction using Be10 and C14. Note the extreme flatness during the Maunder Minimum. It is highly unlikely that SI was so constant for a 70 odd year stretch. Far more likely is that the relationship between SI and the creation of Be10 and C14 breaks down once the SI drops below 1364 W/M-2. (At least using the methodology of Lean et al, anyway)

 

Just so that there is no mistake I'll also point you to Bard et al 2000.

 

Figure 1 in this paper reviews previous work and shows the TSI reconstructions from Lean et al 1995, Hoyt and Schatten 1993 and Zhang et al 1994 and none of them show a measly .5W/m-2 change over 400 years. Figure 3 in this paper shows their own reconstruction and a change of a good 5 W/M-2 for the period 1860 to present.

 

The models might use .5W/M-2 over centuries (which possibly explains their inability to account for modern temps without an enhanced CO2 effect) but the reconstructions show a vastly different situation. I think that I've shown that TSI doesn't change by .5W/M-2 on centennial scales, it changes much more than that and on very short time spans.

 

A final point. Crowley 2000 is referenced by many of the papers and is another Be10 reconstruction. Due to the paywall I can't check but it could be that this is where the long, slow .5W/M-2 comes from. This immediately begs the question that since this would make Crowley 2000 an outlier compared to all the other reconstructions, why use those values and not the ones from the other papers which generally agree with each other and have much higher values?

 

References (To save people having to find them themselves):

 

From the Graph;

González-Rouco et al., 2003 http://w3k.gkss.de/staff/storch/pdf/gonzalez.et.al.2003.soil.pdf

Osborn et al., 2006 http://coast.gkss.de/G/Mitarbeiter/storch/pdf/osborn.magicc-echog.2006.pdf

Tett et al., 2007 http://www.springerlink.com/content/xg6116h0t30g26g2/

Mann et al., 2005b http://journals.ametsoc.org/doi/full/10.1175/JCLI3564.1

Bertrand et al., 2002b http://onlinelibrary.wiley.com/doi/10.1034/j.1600-0870.2002.00287.x/full

Crowley et al., 2003 http://www.sages.ac.uk/home/homes/ghegerl/Crowley.2003GL017801.pdf

Goosse et al., 2005b http://coast.hzg.de/staff/zorita/ABSTRACTS/GoosseXetalGRL2005.pdf

Gerber et al., 2003 http://www.meteo.psu.edu/~mann/shared/articles/GerberClimDyn03.pdf

Bauer et al., 2003 http://www.mpimet.mpg.de/fileadmin/staff/claussenmartin/publications/bauer_al_1000_grl_03.pdf

González-Rouco et al., 2006 http://esrc.stfx.ca/pdf/2005GL024693.pdf

Stendel et al., 2006 http://www.gps.caltech.edu/~vijay/EGU%20Presentations/Climate%20Change/Stendel-etal-06.pdf

 

Also read and/or mentioned;

Bard et al 1997 http://www.college-de-france.fr/media/evo_cli/UPL12772_Bard97EPSL___copie.pdf

Lean et al 1995 http://www.geo.umass.edu/faculty/bradley/lean1995.pdf

Hoyt and Schattern 1993 http://www.leif.org/EOS/93JA01944.pdf

Bard et al 2000 http://www.college-de-france.fr/media/evo_cli/UPL12790_Bard00Tellus___copie.pdf

Crowley 2000 that a number of papers are based on is behind the paywall at Science http://www.sciencemag.org/content/289/5477/270.short

 

Moberg et al 2005 http://coast.gkss.de/staff/storch/pdf/moberg.nature.0502.pdf

MBH 1998 (Mann, Bradley and Hughes) http://www.astro.uu.nl/~werkhvn/study/Y3_05_06/data/talk/14-juni/mannetal1998.pdf

 

Cheers.

[Essay]

Hoy! I'm still working on the reply to your last post. But you raised some unique issues here, so very quickly....

 

You might save yourself some reading if you consider that what you describe as forcings... "quite large and fast" are simply swings of the 11-year solar cycle. By looking at 50 year increments, you go from the beginning of one cycle forward to the middle of another cycle--between 44 and 55 years on. The numbers you are looking at, 2.5, 3, and 4 W/m-2, are typical of the 5 year change (or multiples thereof) in a solar-cycle. It was the change in the long-term solar constant, illustrated by that graph I posted, of a bit over half a Watt changing over 400 years --a slow change in forcing-- that gradually moved us from MWP conditions into LIA conditions.

Um, No.

 

Sorry but that doesn't work. By your own accounts and posting above, the amplitude of a solar cycle is 1.4W/M-2.

~So, what does that have to do with anything? I only offered that "amplitude of a solar cycle" number as a contrast with the long-term change in the solar constant of around half a Watt.

 

You also say that baseline SI won't change quickly and only by about 1 W/M-2 over a long time period. The bottom line of this argument is that the SI rise cannot exceed 2.4W/M-2 and will only reach that after centuries of time. Increase in baseline from Maunder to now is 1W/M-2 plus the Schwabe cycle of 1.4W/M-2 = 2.4W/M-2. The figures you've quoted simply don't allow for more than that figure on a time scale of less than centuries.

~Huh?

 

The graph you posted does not illustrate the long term solar forcing. It shows the long term solar forcing that is used by the models. This means that it is an estimate and not a fact, unless the value can be shown to be correct. The graph doesn't demonstrate this. So what does it demonstrate?

~It is what it is.

 

The IPCC uses Bauer 2003 twice in the graph so I'll start there. (These two are referred to in the IPCC graph as B..2003-14C and B..2003-10Be.) Bauer et. al. 2003 is a reconstruction of SI over the last 1,000 years. They assume a relationship between C14, Be10 and SI so as to use C14 and Be10 as proxies for the SI. Figure 1a in the paper shows the results. According to the C14 proxy during the MWP the SI was about 1368 W/M-2 or 3 W/M-2 above median. This dropped as we went into the LIA with the SI going down to 1362 W/M-2 around 1700AD. (3W/M-2 below median) This then rose again in the instrumental period to the 1368 W/M-2 mark. This is a change of 6W/M-2.

 

The 10Be isn't as marked in variance but is still plus or minus 1 W/M-2 deviation from median.

~Okay, and what is your point?

This is the only SI reconstruction in the graph, all the rest are forcings used as inputs for modelling purposes as is made clear by the description. We must mind the difference between data and facts, musn't we?

~What!? I'd be interested in learning more about what you've discovered relating to these data being "used as inputs for modelling purposes." Do you think that means they were simply "made up" so something could be "used as inputs for modelling purposes?" Please clarify.

 

Again looking at Figure 1a in Bauer, we see that the proxies don't have high resolution in the distant past but show the variations due to the standard solar cycle quite well in the recent past. The one and a bit variance is plainly visible in the post 1850 period.

 

The problem here is that what the graph shows is models that use a .5W/M-2 SI long term variation and a (roughly) 2.6 degree sensitivity to CO2 doubling produce similar curves. This is not a surprise. However it is not proof that the long term variation was in fact .5 W/M-2 for SI. The only paper represented in the graph that is an SI reconstruction places the value at more than 3 W/M-2. In fact I can expand on this a bit. Now that I've located and at least skimmed all the papers in the graph I can say that the graph demonstrates that climate models using the SI from Crowley 2000 and a CO2 sensitivity of about 2.8 degrees agree with each other.

 

One of the problems, or difficulties with paleoclimate is what do we calibrate the models against? The most obvious things are the paleo reconstructions. But which ones? Taking a simple comparison do we use MBH 1998, the "Hockey Stick" which shows a gradual decrease over 1,000 years and a sharp uptick or Moberg 2005 which has a rather more pronounced MWP and LIA? While they are said to be comparable, because they each fall within the others error bars, they are quite different at the 95% level.

 

If Centennial variations are small, then so are the natural forcings. (Talking pre industrial here) An extreme example for this opinion is Tett et al 2007 (TBC 2006 in the graph) Their view is: "These simulations suggest that since 1550, in the absence of anthropogenic forcings, climate would have warmed by about 0.1 K." Bollocks. Ask any historian or Archaeologist if the climate anywhere has been that stable for 450 years ever, the answer is "No". Sorry but his model is wrong. Be that as it may, an assumption of slow and small natural climate change requires natural forcing changes to be slow and small as well.

~Gosh that's a lot of supposition on your part.

 

I've linked to Bauer to show that the SI reconstuction is for a 6 W/M-2 change in SI between the Maunder and now. Many of the papers reference Lean et al 1995.

I draw your attention to Figure 2 in that paper where the reconstruction shows a maximum of 1364 W/M-2 for STI during the Maunder rising to a (then) figure of 1368 W/M-2 a change of 4 W/M-2. Lean et al is also a reconstruction using Be10 and C14. Note the extreme flatness during the Maunder Minimum. It is highly unlikely that SI was so constant for a 70 odd year stretch. Far more likely is that the relationship between SI and the creation of Be10 and C14 breaks down once the SI drops below 1364 W/M-2. (At least using the methodology of Lean et al, anyway)

~LOL!

Just so that there is no mistake I'll also point you to Bard et al 2000.

 

Figure 1 in this paper reviews previous work and shows the TSI reconstructions from Lean et al 1995, Hoyt and Schatten 1993 and Zhang et al 1994 and none of them show a measly .5W/m-2 change over 400 years. Figure 3 in this paper shows their own reconstruction and a change of a good 5 W/M-2 for the period 1860 to present.

 

The models might use .5W/M-2 over centuries (which possibly explains their inability to account for modern temps without an enhanced CO2 effect) but the reconstructions show a vastly different situation. I think that I've shown that TSI doesn't change by .5W/M-2 on centennial scales, it changes much more than that and on very short time spans.

 

A final point. Crowley 2000 is referenced by many of the papers and is another Be10 reconstruction. Due to the paywall I can't check but it could be that this is where the long, slow .5W/M-2 comes from. This immediately begs the question that since this would make Crowley 2000 an outlier compared to all the other reconstructions, why use those values and not the ones from the other papers which generally agree with each other and have much higher values?

~see below:

 

References (To save people having to find them themselves):

 

From the Graph;

González-Rouco et al., 2003 http://w3k.gkss.de/s...l.2003.soil.pdf

Osborn et al., 2006 http://coast.gkss.de...-echog.2006.pdf

Tett et al., 2007 http://www.springerl...6116h0t30g26g2/

Mann et al., 2005b http://journals.amet...1175/JCLI3564.1

Bertrand et al., 2002b http://onlinelibrary...02.00287.x/full

Crowley et al., 2003 http://www.sages.ac....003GL017801.pdf

Goosse et al., 2005b http://coast.hzg.de/...etalGRL2005.pdf

Gerber et al., 2003 http://www.meteo.psu...erClimDyn03.pdf

Bauer et al., 2003 http://www.mpimet.mp...1000_grl_03.pdf

González-Rouco et al., 2006 http://esrc.stfx.ca/...005GL024693.pdf

Stendel et al., 2006 http://www.gps.calte...del-etal-06.pdf

 

Also read and/or mentioned;

Bard et al 1997 http://www.college-d...PSL___copie.pdf

Lean et al 1995 http://www.geo.umass...ey/lean1995.pdf

Hoyt and Schattern 1993 http://www.leif.org/EOS/93JA01944.pdf

Bard et al 2000 http://www.college-d...lus___copie.pdf

Crowley 2000 that a number of papers are based on is behind the paywall at Science http://www.sciencema.../5477/270.short

 

Moberg et al 2005 http://coast.gkss.de...nature.0502.pdf

MBH 1998 (Mann, Bradley and Hughes) http://www.astro.uu....annetal1998.pdf

 

Cheers.

~Thanks, but....

 

Clearly, all of these authors, the publishing journals, and the IPCC have overlooked all the errors that you've discovered here; or ...you have misunderstood some of their methods for reaching conclusions.

 

I'm gonna stick with their conclusions, until you notify them of their mistakes and sloppy work (and you become famous for setting science back on a valid track).

===

 

Notwithstanding the "large" swings (2 to 4 Watts/m-2) from maxima and minima of the 11-year solar cycle (or short-term multiples thereof) that you seem to be focusing upon....

 

The IPCC graph in post # 32 I posted, based on a compilation of those citations you posted:

http://www.sciencefo...post__p__613805

 

...clearly shows forcing by long-term average solar insolation changed by about (slightly over) half a Watt over 400 years, from 1100 to 1500, when we shifted from ongoing MWP conditions to the onset of LIA conditions.

The graph may be wrong, but that is what it shows.

===

 

But, however this graph was created....

I'm assuming you see that this is a graph of the long-term "average" for the solar constant (expressed as solar irradiance forcing in W/m-2), right?

 

Is your skepticism then based on your suggestion about poor work done by the authors, the journals, and the IPCC graph above; or is it based on what the IPCC graph shows about climate ...about how less than a Watt of forcing, over 400 years, noticeably changes the climate?

 

~bbl

[Essay]

...finally got this finished....

I hope lunch was enjoyable.

 

Yes, I should have given kudos for Anthropology but it was well past midnight and I was damn near asleep. Please accept the kudos now.

 

The problem with Archaeology or Anthropology in this case is that most of the evidence that they can supply is qualative rather than quantative. For example we can know that the climate changed at the end of the Roman Warm Period and became much colder, but we can't tell how much colder in degrees. So if we are looking to quantify the differences, the records are of limited value except as a general check.

 

As an aside. That's what first interested me in the actual science. I saw the "Hockey Stick" and I knew from my readings in History that the NH climate didn't look like that. People forget that the word "school" derives from the ancient Greek word meaning "leisure". IOW, you have to be able to take time out from simply surviving to be able to have education. One of the reasons for the "Dark Ages" was simply that times were very hard indeed. When the warmth returned in the MWP, education flourished in many ways simply due to greater crop yields allowing more food and more leisure time. The reconstruction simply didn't match the observed facts of life during the period. (I've noticed some historians over at Judith Currys blog that feel the same way.)

~I'd love a citation for anything written by a historian on climate, if you can....

~[but] The "Hockey Stick" didn't match the facts of life for which period; the Dark Ages?

 

~Well, whatever.... It was in the late 90's, after I first saw the Vostok 400 kyr record, when I realized ...what we consider as significant climate change (LIA/MWP) is in fact unusually stable climate, relative to an evolutionary time scale; and I thought about how lucky we've been, and how we should not take that luck (or "intelligent design" of Gaia) for granted--not pushing our luck, or the design of the current equilibrium too much. Now that we know we affect the equilibrium, we should endeavor to manage it more judiciously, with providence (not profit) in mind.

===

 

I take your point re data, but I find that sometimes the reconstructed "data" is presented as "fact", and this concerns me. Not picking on Dr. Mann, but MBH 1998 by its iconic nature was pretty well presented as "fact" in the TAR, for example. As the old saying goes "You are entitled to your own opinion, but not your own facts".

~It "pretty well" is what it is, regardless of how the media or bloggers "sometimes... presented" it.

...AND it remains a valid reconstruction, and is virtually the same, even after the "questionable" tree-ring data were removed --from what I read in the scientific literature.

===

 

There is nothing wrong with building on previous works, "shoulders of giants" and that sort of thing. However it is always worthwhile to go back to basics occasionally. Someone building on Bauer might not realise that large chunks are based on Brovkin and may not realise the assumptions Brovkin is based on. So an error can be perpetuated. I'm one of those picky people who tends to read the papers that papers are based on which means instead of reading one, I finish up reading 6 or 7. I think this approach is needed for the amateur trying to understand climate science. I need to understand not just what is said, but where it comes from as well. Which is a bugger because CS is barely a hobby for me and takes time out from important things like learning dead languages.

~You can probably tell CS is a lot more than a hobby for me. I've spent 40 years studying physical, biological, and earth/environmental sciences; along with enough social sciences like history, anthropology, and economics to enjoy life.... I like etymology as a sort of hobby; I enjoyed "An Exaltation of Larks" by Lipton, a few years back.

===

 

I have to disagree with the idea that forcings change slowly enough for the climate to respond in tandem. If we assume that Bauer et al 2003 was correct in the reconstruction of SI forcings. it's quite obvious from Figure 1a that SI forcings are quite large and fast. A rise of 2.5W/M-2 between 1050 and 1100, 2.5 W/M-2 from 1340 to 1370, a drop of over 4 W/M-2 from 1370 to 1450 and a rise of 3 W/M-2 from 1700 to 1750. The rate of change of these SI forcings makes the 2.4 W/M-2 from 1850 to present pale in comparison.

~It didn't start out at 2.4 W/m-2; but as it has built up over the past century, the climate has changed in response --as fast as it can-- and will continue to do so for centuries to come, or at least until the ice sheets fully adjust, climate patterns change, and some new equilibrium (4 to 6 times the LIA/MWP difference) develops.

===

 

(And I'd still like to know why this diagram was misrepresented in IPCC graph. Maybe there is some maths that I haven't learnt yet where 1368-1365= .6, but i doubt it.) I'll have to read the other SI papers to see a comparison.

~You might save yourself some reading if you consider that what you describe as forcings... "quite large and fast" are simply swings of the 11-year solar cycle. By looking at 50 year increments, you go from the beginning of one cycle forward to the middle of another cycle--between 44 and 55 years on. The numbers you are looking at, 2.5, 3, and 4 W/m-2, are typical of the 5 year change (or multiples thereof) in a solar-cycle. It was the change in the long-term solar constant, illustrated by that graph I posted, of a bit over half a Watt changing over 400 years --a slow change in forcing-- that gradually moved us from MWP conditions into LIA conditions. <reprise>

~So our 2.4 Watts does not "pale in comparison," but dwarfs the 0.6 Watt forcing of those centuries.

===

 

I'm not a fan of the "Anthropocene" concept. It often seems to be pushed by people with an ideological barrow. They seem to have the idea that everything was rosy and nature was in "delicate balance" and "harmony" until those nasty humans came along and messed things up. Speaking anthropologically, mankind has never liked the idea of being at the mercy of anything, we like to think we can control things. 10,000 years ago this led to the "Nature" religions wher people believed they could influence the weather if they appeased the rain God. This took many forms, from personal mutilation to killing heretics to show the relevent god just how much we dislike people who don't worship the rain god. In the time of the LIA we'd moved from nature gods to the christian one. People believed that the very cold year of 1626 was caused by witches "cooking" the weather and 4,400 people were executed for "controlling" the weather.

~Yes, some seemingly reasonable people can be exceptionally idiotic at times, eh?

===

 

This speech by Sallie Ballunis is quite clear and points out that even the reasons used for some of the trials are the same words as we hear today in the climate debate.

<YouTube of Sallie Ballunas>

~OMG, the same words?! You must be referring to how severe weather was characterized as: "It's unnatural!"

Well that clinches it, eh? It's just like with the witch trials. Yep, the climate debate must only be simpletons fearmongering; nothing to see here folks, just move along... it's all "quite clear."

 

~While I'm sure this is not just another idiot with a microphone, though the edited clip doesn't help convey that, I have a problem with the credibility of a source that can't even get the name spelled correctly.

 

~I see she worked with Willie Soon, on a Heartland Institute publication. D'ja catch the news yesterday?

http://www.reuters.c...E75R2HD20110628

June 28, 2011

(Reuters) - Willie Soon, a U.S. climate change skeptic who has also discounted the health risks of mercury emissions from coal, has received more than $1 million in funding in recent years from large energy companies and an oil industry group....

....

Last year, the foundation of Charles Koch, chairman and CEO of privately held Koch Industries, gave Soon $65,000 to study how variations in the Sun are related to climate change.

 

Koch is co-owned by David Koch, founder of Americans for Prosperity, a group aligned with the Tea Party movement, which opposes new air pollution regulations.

 

Beginning in 2002, Soon's funding mostly came from oil companies, including Southern Co, one of the largest coal burners in the United States, and the American Petroleum Institute, according to documents uncovered in a Freedom of Information Act request by Greenpeace and seen by Reuters.

...

Soon was criticized by many climate scientists for a 2003 paper he co-wrote, concluding that 20th century warming was not unusual compared to that of centuries past. About 5 percent of the study's funding, or $53,000, came from the American Petroleum Institute....

....

Southern gave Soon $120,000 starting in 2008 to study the Sun's relation to climate change, according to the FOIA documents. Spokeswoman Stephanie Kirijan said Southern has spent about $500 million on environmental research and development and funding and did not fund Soon last year.

....

Soon also got $131,000 from oil major Exxon Mobil Corp in 2007 and 2008 received grants to study the Sun's role in climate change and global warming in the Arctic, Greenpeace said.

In 2008, Exxon said it would stop funding groups that divert attention from finding new sources of clean energy.

Exxon spokesman Alan Jeffers said this week the company did not fund Soon last year and that it funds hundreds of organizations to do research on climate and the environment.

....

Soon agreed he had received funding from all of the groups and companies, but denied any group would have influenced his studies. "I have never been motivated by financial reward in any of my scientific research," he said.

"I would have accepted money from Greenpeace if they had offered it to do my research," he added.

Well, that's just Davies' opinion ...and Willie's word... and doesn't mean anything, right?

===

 

I currently view the "Anthropocene" idea as one pushed by people who can't accept that mankind is a rather insignificant speck in a great, wonderful, amazing and rather hostile and uncaring Universe. The Anthropocene idea gives the impression that we have power over nature, rather than being at the mercy of nature. And nature has no mercy.

~I thought we were given dominion over nature back in 4004 BC, but that's just from some unreliable, oral history thing I read.

 

~Ruddiman indicates the same time range though, about 6000 years ago, for early influences; when we started widespread agriculture, and we started using fire (and forests) to fuel the Copper Age, Bronze Age, and finally the Iron Age.

===

 

PS. I don't think I've read Ruddiman, although the name is familiar. I'll have a read of the books you say and see if I change my opinion.

~Before reading Ruddiman, look over that first graph you posted and notice how stable (relatively) our climate has been over the "Anthropocene" ...compared with any previous 10,000 year era since we split from the chimps.

What are the odds on that?

===

 

~

 

~p.s. ...odds of about 1 in 700? That alone should qualify it as a new Age, the Anthropocene; not to mention the loss of megafauna and other biodiversity, along with the addition of agriculture and fire, and the reworking of the biosphere they wrought, (oh, and) plus some new, non-glacial climate regime. It should be at least as significant as the PETM, the dawn of the Eocene, don't you agree?

Edited July 1, 2011 by Essay

[JohnB]

Okay, taking it from the top.

 

About amplitudes and change. You said that;

The numbers you are looking at, 2.5, 3, and 4 W/m-2, are typical of the 5 year change (or multiples thereof) in a solar-cycle.

 

I'm pointing out that the numbers don't add up. If you're right about the slow, long term .5W/M-2 change, then we can visualise a combination of this with a solar cycle. What you would have is a 1.4W/M-2 cycle superimposed over the top of the slow .5W/M-2 change. This means that if we compare the bottom of a solar cycle while in the low part of the long cycle with the top of a solar cycle in the high part of the long cycle, the difference cannot exceed 2.4W/M-2. The change in solar cycle is 1.4W/M-2 increase superimposed on the 1W/M-2 change in the baseline forcing. 1+1.4=2.4. Note that since the baseline change is assumed to be long, then this maximum difference can only happen over a century or two.

 

Consequently you can't claim a 3 or 4W/M-2 change is due to solar cycle change unless you think the solar cycle changes by far more than 1.4W/M-2. The only way that you can get 4W/M-2 over a 50 or 60 year period is if the baseline solar forcing changes at a much faster rate than you are assuming. You can't have a 1W/M-2 change over centuries coupled with a 1.4WM-2 solar cycle and also have a 4W/M-2 change over 60 years. There can be one or the other, but not both. Does that clear up what I meant?

 

Concerning the graph, it is what it is. It is a graph of the climate forcings used as inputs to the climate models. This immediately begs the question "Are those values correct?". What do the reconstructions say about the changes in SI over the last 1,000 years? I posted links to 4 different papers that were all SI reconstructions and all show that the long term solar forcing changed much more and much faster than the values used by the models. I have no idea why the IPCC chose to use the values they did, ask them if you want. I'm simply pointing out that the assumption of a long, slow .5W/M-2 change is in direct contradiction to what the reconstructions say happened. I invite you to reread the Bauer paper and tell me if you can find anything in it that even implies that the long term forcing was .5W/M-2. Figure 1a clearly shows the solar forcing going from a high of 1368 W/M-2 around 1250 AD to a low of 1362 W/M-2 in 1700 and back up to 1367/1368 today. I, personally would really love to know how these figures can be squashed into a .5W/M-2 figure.

 

If you can point me to some physical reconstructions that show the long term change is in fact .5W/M-2 I'll happily read them. Until then you are in the unhappy situation of claiming the .5 value is right because the models use that value and that the models wouldn't use that value if it wasn't right right. This is circular reasoning, great for theological discussions but very poor science.

 

I'm not too sure exactly what you thought was a "lot of supposition on my part". The point I was trying to make is that the climate reponse is proportional to size and rate of change of the forcing. For example, if the TSI went up by 5W/M-2 tomorrow the climate would change rapidly, if it went up the same amount over 300 years the climate would change much slower. The final result would be the same, but the rate of climate change would be different.

 

This is tied in with what I was getting at re temperature reconstructions. If you think that the hockey stick is an accurate representation, ie, a long, slow gentle decline over centuries, then this neccessarily precludes any large changes in SI forcings. You can't have the TSI swinging up down by 6-10W/M-2 while the temps gently decline. You would have to postulate incredibly long lag times. If, OTOH you think as I do that the temps go up and down quite a bit and quite quickly, then rapid and large changes in TSI don't worry you because you pretty much expect them. For the climate to change a lot, rapidly, requires forcings to do so as well. I add that even a cursory look at Greenland or Antarctic cores show that the climate does indeed change a lot, and very rapidly when it wants to.

 

I don't see what was funny in my comment about Lean et al. While using C14 and Be10 their reconstruction was based primarily on sunspot numbers. During the Maunder Minimum the number of sunspots fell to zero. To attempt to reconstruct SI of lower than 1364 W/M-2 would have required them to postulate negative sunspot numbers, something that would be amusing. It was a limitation to the methodology used in that paper. Other reconstructions, Zhang, Bard and the others are not reliant on sunspot numbers and could therefore reconstruct lower values.

 

Second post.

 

I doubt that there are many papers about climate change by historians. This is what I meant earlier when I said history provides qualitive but not quantitive data. In truth I don't think climate change was thought to be a factor until recently in many cases, it was simply assumed that some societies were "wiped out" by their neighbours, or disease, or they just "died out", or it was assumed that land practices were bad and reduced crop yields were from that cause rather than climate change. With better techniques and data we now know that climate change was a deciding factor in many cases.

 

Some simple examples.

 

The settling of Pharonic Egypt. These people were originally oasis dwellers in the Sahara. Oases in 3,600 BC weren't like they are now and many of them supported populations in the tens of thousands. Somewhere around 3,100 BC something changed. Water tables dropped or rainfall changed somewhere, but the oases started drying up forcing the people to move. They migrated east and settled in the Nile valley to become the Egyptians. So climate change is now known to be directly responsible for the founding of Pharonic Egypt.

 

Anybody with knowledge of high school history knows that this civilisation revolved around the annual flooding of the Nile. (It was part of the Pharoahs job as the "Living God" to keep the floods happening on time.) Egyptian history tells us of "Intermediate" periods that separated the Old, Middle and New Kingdoms. These periods were times of unrest and loss of central control by Pharoah. The interesting thing is that these times were also marked by a strange change, the Nile stopped flooding or floods were very poor. This reduced Pharoahs power and influence. However the only thing that cause the Nile flood to fail for extended periods is a massive change in rainfall patterns, ie climate change. The first Intermediate period lasted for 140 years, the second for 190 years and the third for nearly 400 years. Not all of the time spent in the intermediate periods can be ascribed to climate, there were many other factors as well, but the records do tell of decades when the Nile simply didn't flood. The records also tell us that this wasn't a slow process with gradually degreasing floods, the change was quite rapid, a decade or two at most. (And they came back as quickly) The only possible explanation is rapid changes to the local climate effecting the raifall in the Nile catchment.

 

Rome. At roughly the time of Julius Ceasar we know from the records that crop yields declined rapidly in Italy and Egypt was required by the Empire as a tributary nation simply so that Rome could feed itself. It was Romes reliance on Egyptian grain that gave Anthony and Cleopatra the chance they needed to try for Empire.

 

The Indus. The Harappan civilisation of the Indus Sarasvati region was superior in many ways to its African and European contemporaries. Uniform weights and measures, large scale farming and building abilities, covered drains, proper sewerage, these guys were bright. So far over 1,000 cities and settlements have been found for this culture. They had trade with Mesopotamia, huge granaries and yet their survival, like the Egyptians was dependent on the rivers they lived along. At their height in 2600-1900 BC, signs of problems by 1800 BC and the cities deserted by 1700Bc. No wars, no destruction no signs a plague wiped them out. The most probable cause was climate change from 1800BC onwards, the rivers no longer provided enough water for the civilisation to survive.

 

The Anasazi. Recent research shows the "Peublo People" had quite sophisticated farming techniques, but they were destroyed by the "Great Drought" from 1150 to 1450 AD. No matter how good your techniques, you can't water plants if the rain doesn't fall.

 

Tiahuanaco on the shores of Lake Titicaca. Same deal. Very advanced farming techniques but the climate changed and the rain stopped falling. The city died. they went from bountiful food to nothing in the period 950-1,000 AD, fifty years to destroy an entire culture. And these guys were really good at crop raising. To quote Wiki;

 

The high altitude Titicaca Basin required the development of a distinctive farming technique known as "flooded-raised field" agriculture (suka kollus). They comprised a significant percentage of the agriculture in the region, along with irrigated fields, pasture, terraced fields and qochas (artificial ponds) farming. Artificially raised planting mounds are separated by shallow canals filled with water. The canals supply moisture for growing crops, but they also absorb heat from solar radiation during the day. This heat is gradually emitted during the bitterly cold nights that often produce frost, endemic to the region, providing thermal insulation. Traces of landscape management were also found in the Llanos de Moxos region (Amazonian food plains of the Moxos). Over time, the canals also were used to farm edible fish, and the resulting canal sludge was dredged for fertilizer. The fields grew to cover nearly the entire surface of the lake and although they were not uniform in size or shape, all had the same primary function.

 

Though labor-intensive suka kollus produce impressive yields. While traditional agriculture in the region typically yields 2.4 metric tons of potatoes per hectare, and modern agriculture (with artificial fertilizers and pesticides) yields about 14.5 metric tons per hectare, suka kollu agriculture yields an average of 21 tons per hectare.

 

Significantly, the experimental fields recreated in the 1980s by University of Chicago´s Alan Kolata and Oswaldo Rivera suffered only a 10% decrease in production following a 1988 freeze that killed 70-90% of the rest of the region's production. This kind of protection against killing frosts in an agrarian civilization is an invaluable asset. For these reasons, the importance of suka kollus cannot be overstated.

 

1,000 years ago they were getting yields 50% higher than modern methods, yet climate change wiped them out in under a century.

 

There are plenty more examples but they all tell the same story. We know the climate changed, sometimes very rapidly, but we don't know which way or how much. The Harappans died out because the rain stopped, but is rain reduction in the Indian Subcontinent a result of warming or cooling? And which ever it is, how big was the change? History can tell us where there were rapid and large changes, but it can't tell us the sign or magnitude of the change. There are exceptions, like the Romans and parts of Egyptian history where we find that thaws and snow falls come earlier or later to give us the sign of the change, but they still don't give us the magnitude.

 

Well, whatever.... It was in the late 90's, after I first saw the Vostok 400 kyr record, when I realized ...what we consider as significant climate change (LIA/MWP) is in fact unusually stable climate, relative to an evolutionary time scale;

 

I thought the same and so I asked about it. It turns out that the Holocene is not unusual at all, you just have to go far enough back to when the Milankovitch cycles roughly line up the same way. This is called "Stage 11" in the literature and is the reason that nobody is expecting an Ice Age anytime soon. The last time the cycles were like this the Interglacial lasted for between 20,000 and 40,000 years, just like we expect this one to. I actually used the words "unusually stable" in my question and the response was "Actually it isn't" and I was pointed in the direction of further reading on the subject.

 

So our 2.4 Watts does not "pale in comparison," but dwarfs the 0.6 Watt forcing of those centuries.

 

Tell you what. I've produced 4 different peer reviewed reconstructions that show the solar forcing to be much greater than .6 W/M-2. How about you produce one to show the value is correct?

 

OMG, the same words?! You must be referring to how severe weather was characterized as: "It's unnatural!"

Well that clinches it, eh? It's just like with the witch trials. Yep, the climate debate must only be simpletons fearmongering; nothing to see here folks, just move along... it's all "quite clear."

 

~While I'm sure this is not just another idiot with a microphone, though the edited clip doesn't help convey that, I have a problem with the credibility of a source that can't even get the name spelled correctly.

 

Yes, the same emotive words. That was the point. Hysteria often uses the same cliches. Funny as it might seem, but after having Hansen refer to coal trains as "Death trains" with the obvious Holocaust reference, plus the unseemly word "denier", add to that calls by David Suzuki that sceptics be prosecuted for "Crimes against future Humanity" or some such. We had Joe Romm wondering when it would be okay to "strangle deniers in their beds" and Greenpeace last year saying "We need people willing to break the laws" and reminding sceptics that "We know who you are and we know where you live" culminating with the 10:10 splatter fest with sceptical people being blown up.

 

My personal favourite is from fellow Aussie Jill singer;

I'm prepared to keep an open mind and propose another stunt for climate sceptics - put your strong views to the test by exposing yourselves to high concentrations of either carbon dioxide or some other colourless, odourless gas - say, carbon monoxide.

 

You wouldn't see or smell anything. Nor would your anti-science nonsense be heard of again. How very refreshing.

 

Although Richard Glovers;

Surely it’s time for climate-change deniers to have their opinions forcibly tattooed on their bodies.

was good too.

 

Some of us are pretty sure that some of the other side aren't playing with a full deck.

 

I suppose that this is more about how the debate has been phrased than the science involved. There are idiots on both sides. Your side has people like 10:10 who fantasise about killing their opponents and we have the non scientific idiots who don't even think the world has warmed. But I suppose every family needs a crazy relative.

 

BTW, I thank you for the tone of your responses. I much prefer an honest and civil exchange of ideas and arguments to a slug fest of name calling.

 

Before reading Ruddiman, look over that first graph you posted and notice how stable (relatively) our climate has been over the "Anthropocene" ...compared with any previous 10,000 year era since we split from the chimps.

What are the odds on that?

 

As I said above and considering the Milankovitch cycles, about 100%. The Holocene is not unusual in any way.

 

And yes I did hear the news about Willie Soon, what a pity it wasn't "news". Greenpeace should have simply read his papers instead of launching FOI applications because Dr. Soon puts the funding bodies in his acknowledgements. IOW, if you read the papers you know who he was funded by. There was nothing secret or hidden, it was quite up front.

 

Are you making an accusation of scientific fraud on the part of Dr. Soon, or are you simply joining Greenpeaces whispering campaign? If there is an accusation to make, then I suggest somebody make it.

 

This is the most disgraceful part of the climate debate IMO. Does 2+2 somehow not equal 4 if the claimant gets some oil funding? So we should only trust scientists funded by Greenpeace? Or only those funded by the renewables industry? Or government?

 

If Dr Soons research is wrong then that can be demonstrated for the world to see. (Remember we are talking about peer reviewed papers here, so I can only presume that the reviewers and Journal editors were also somehow paid off by "Big Oil" to allow the paper to be published.) It's that simple. Show that he is wrong, demonstrate it, prove it, that is how science works. (Or at least that is how it's supposed to work.)

 

There is only one reason to descend to grubby character assassination. Greenpeace and others can't find anything wrong with his science, so the only tactic left is to smear the Drs name and hope that nobody will listen to him. An unusual tactic indeed if the science is "settled", strong and well proven wouldn't you say?

 

"Science" doesn't care where the funding comes from. Science cares about what is provable. Whether from Greenpeace, or from oil funding or from the Heartland Institute, if the assumptions can be shown to be correct and the maths is right, then the science is probably right. The funding is irrelevent to the science, it's only relevent if you want to run a smear campaign and have no science left to prove your case. Good science is open and transparent, putting up ideas and daring others to poke holes in them. The more an idea is attacked and the attacks are answered the better and stronger the science gets. Relativity isn't a strong theory because it was never attacked, it is a strong theory because it has beaten everybody who tried to prove it wrong.

 

In contrast anybody who doubts "climate science" is supposed to be some sort of creationist or flat earther. Good science doesn't deny data access and hide behind IPR, it's out there and takes on all comers. The only reason I can think of to hide things and refuse to respond to criticism is because you have no ability to prove your idea in the light of day. That can be called many things, but "science" isn't one of them.

 

A final thought. There is an interesting psychological phenomena called "Projection" where we project onto others our own behaviour. A congenital liar simply assumes that their opponent is one too. I wonder why Greenpeace et al think that sceptics are biased, lying, fudging the data and producing junk science?

 

PS. The megafauna started dying out some 2 million years ago. The most probable cause that I can think of is the changes to the climate from the land bridge forming between North and South America. This of course blocked the equatorial current that used to flow from the Atlantic into the Pacific and resulted in major climate changes. I'm aware that many believe man to be responsible and for some this may be correct. However the fact cannot be ignored that the megafauna died out everywhere, including places that man had never been. Many (maybe most) were gone long before H. Sapiens had even evolved, so it's a bit of a stretch to blame humans for the extinction of the megafauna.

 

The great Sabre tooth died out because the climate changed and the forests it hunted in became grasslands, populated by fast running deer. It simply couldn't keep up to their speed. That amazing Elk in N America with the 10 foot wide antlers would have been fine in tundra or grasslands, but if they give way to forests due to climate change that those antlers become a hinderance trapping the animal and preventing it from escaping things like wolves.

[Essay]

Hey, thanks for the history points!

Big day today, but I can add a few "quick" points before things get going.

===

 

First, that was my mistake; bringing up Dr. Soon. I was trying to mirror your reference to a video link, and point out how irrelevant it was... as when I asked if you agreed with: "Well, that's just Davies' opinion ...and Willie's word... and doesn't mean anything." Reuters seemed like a reasonable citation, but where do you get that vile stuff you post? (asked rhetorically... please don't actually tell me).

===

 

Second, I thought these were a lot of suppositions for one paragraph.

 

"If Centennial variations are small, then so are the natural forcings."

"Bollocks. Ask any historian... the answer is 'No'. "

"Sorry but his model is wrong. "

"...an assumption of... requires ...as well."

===

 

So finally, about the solar forcing.... Obviously my problem is trying to use the IPCC graph that shows about a half Watt of forcing over 400 years (1100-1500AD). I was trying to make the analogy between then and what we could expect 300 years in the future, after a larger (for 100 years already) forcing... and how we might expect a larger climate shift than the LIA/MWP shift.

 

I'm not sure why you keep talking about (and quoting) individual solar-cycle data points for comparison. Those data point are only used for constructing the long-term average of the solar constant, aren't they? It is that particular average, displayed as the graph of solar forcing I posted, that provided the analogy for me to ask about climate change over the next few centuries... and skepticism thereof.

 

You've stated several times how you don't understand how the lines on the graph (the long-term average SI forcing) are derived from data sets that you quote from; and I believe you. I haven't looked for myself; but I'm confident that people, who do understand how the long-term averages are constructed from the data sets, have checked and been satisfied with the methods, the conclusions, and the graphs.

===

 

Also, you talked about the rate of forcing, which I think is an interesting topic and something that I should learn more about. I will try to start a new topic soon on that subject.

===

 

One more point....

 

The graph I posted:

http://www.sciencefo...805#entry613805

 

...also showed volcanic forcings at the top, and "all other forcings" at the bottom. I suppose CO2 is included in that last group, but it didn't vary too much back then. Do you think there are missing forcers on these graphs, or that these graphs are not fairly accurate?

===

 

In that post I ended by saying: "We are now adding a similar forcing, which is an order of magnitude greater than the difference between the MWP and LIA forcing, to our climate system--for what will be a longer duration. To believe that the system will continue operating as before, with what some describe as simple "variability," takes a lot of faith. Of that judgement, I'm very skeptical."

 

I'm skeptical that the climate will not change "unnaturally;" skeptical that it will not respond proportionally to the change between MWP and LIA conditions, for a similarly proportional "unnatural" forcing over a similar time span. [btw... I don't mean "supernatural" here, as your witchtrials probably supposed; so please don't bring that up again] I think "unnatural" simply means anthropogenic in this context.

 

{Sidenote} Oh hey! That last point "over a similar time span" made me realize what you've been trying to say with all that addition/subtraction of forcings you were doing. I had hoped on a second reading it wouldn't sound quite so WTFy, and now I'm sure it will make sense... if I assume you think that a change due to the solar-cycle forcing manages to fully express itself in the climate. ummm... That's not the best way to put that; it's more as if you think one or two Watts can fully express its effect within a few years, or with not much lag to fully affect the system.

 

That would explain why this: " A rise of 2.5W/M-2 between 1050 and 1100, 2.5 W/M-2 from 1340 to 1370, a drop of over 4 W/M-2 from 1370 to 1450 and a rise of 3 W/M-2 from 1700 to 1750. The rate of change of these SI forcings makes the 2.4 W/M-2 from 1850 to present pale in comparison."

...made sense to you.

 

Definitely a new topic about lag times, response rates, and forcing rates is needed.

{End sidenote}

 

And so it seems your skepticism is about how the science is done, how complete is the existing science, and how complete is the total understanding of climate dynamics, if I'm getting the gist of your posts; and not skepticism of what the climate might do if AGW theory is valid. Is that correct?

 

~Later

[JohnB]

Hmmm, we seem to have got our wires crossed a bit, so perhaps I can clarify what I meant by certain things.

 

I normally don't consider the 11 year solar cycle for the simple reason that the climate can't adjust fast enough to warrant concern. I generally think about it as a wiggle about .7 W either side of a long term solar forcing curve. For the same reason I disregard the change in solar forcing due to earths eccentricity in its orbit, this annual change is too fast for the climate to keep up with.

 

When I talk about a change in forcing, I don't mean a blip, I mean a change in the baseline, say from 1364 - 1366 W/M-2, something that endures for decades and not just a year or two. You still have the 11 year wiggle and reactions to volcanics etc, but it's the baseline that's important.

 

This is where my assumptions come from. A small change in the baseline rate will cause a small change in climate whereas a large change in baseline rate will cause a large change in climate. So a change in TSI from 1350-1360 W/m-2 will cause a much larger change in the climate than a change from 1350-1352 W/M-2. The assumption is simply that the change in climate is proportional to the change in forcing. I think it is also a reasonable assumption that the rate of change of the climate is proportional to the rate of change of the forcing. (Up to a cerain point, there must be a limit. However the ice cores show us that temp changes can be measured in degrees per decade, so the limit is very fast.)

 

From this we can conclude that if temps changed only a little and the rate of change was low then the change in forcing was small and the rate of change was small. For example if TSI went from 1362 - 1362.5 W/M-2 and took 100 years to do it, then we would expect the change in climate to be small and the rate of change of the climate to be slow. If however the TSI changed from 1362 - 1368 W/M-2 and did so over only a ten year period, then we would expect the climate to change a lot more and a lot faster. (A supervolcano works just as well, but the forcing is in the opposite direction. Gigantic dust cloud in the atmosphere for 50 years dropping the SI baseline, the climate would react very quickly.)

 

Now to the reconstructions. I pointed out that Bauer et all shows changes in solar forcings of 2.5, 3 and 4 W/m-2 on short time scales which you said are typical of changes in the solar cycle, by which I presumed you meant the 11 year sunspot cycle. Since the solar cycle is a .7 W/M-2 wiggle either side of the baseline solar constant, this cannot be responsible for a 4 W/M-2 change over 50 years unless the baseline constant changes dramatically. (Try it with a piece of graph paper. Draw a line as the baseline that slowly changes by .5 of a box and superimpose on that line a wiggle that moves .7 of a box above and below that line. There is no way you can get that line to move 4 boxes. The numbers don't add up.)

 

However, the IPCC graph contends that the baseline only changes by .6 W/M-2 over 100 years or so.

 

This leads to only one of two possibilities being true;

 

1. The IPCC graph is correct and the baseline changes by .6 W/M-2 over centuries. or

2. The reconstructions are correct and the baseline changes by 6 - 10 W/M-2 (and can do so in decades) and the IPCC figures are wrong.

 

An important distinction needs to be made here. The graph is not a graph of reconstructed forcings, it is a graph of the inputs used by the models. These are two totally different things. The values were not independently derived but resulted from a series of "curve fitting" exercise. There is nothing wrong with this per se, but to continue. The grey area in the lower part of the IPCC graph shows the overlap of uncertainties of the paleo reconstructions. this is shown in the bottom part of Figure 6.1 below;

 

So the brown bit in this graph became the grey bit in yours. From there the question is simple. "What forcings do we have to feed the models to simulate temps that fall generally within the grey bit?". The result is a,b and c in your graph with the simulated temps being d. Some people rail against curve fitting but I think it's quite useful in this context, but remember we are working backwards here, we are deriving the changes in the solar constant forcing by curve fitting the reconstructed temperatures.

 

But the derived solar forcings don't match the reconstructions, so there must be a problem somewhere. The thing is that I take the concept of "Nullus in Verbia" as a cornerstone of the scientific method. We have three things here, the reconstructed forcings, the models and the reconstructed temperatures. I'll be happy when we can feed the reconstructed forcings into the models and get the reconstructed temps as an output. Then we will know that we are doing it right.

 

So why did the IPCC agree with the lower figure? Where did the .5 W/M-2 long term change some from? I'm glad you asked. Section 2.7 states;

The estimates of long-term solar irradiance changes used in the TAR (e.g., Hoyt and Schatten, 1993; Lean et al., 1995) have been revised downwards

 

This is explained in Section 2.1.7.1 as being due to a new reconstruction by Y. Wang et al. Looking at the Co-authors we find J.L. Lean. J.L. Lean is also one of the lead authors for WG1, Chapter 2, and the only solar physicist on the lead author team. The "revised downwards" values from Chapter 2 are the values used by chapter 6.

 

Now maybe Dr. Lean is correct and all the previous reconstructions are wrong. However asking me to agree to that on the basis of a report that she wrote and only providing as proof a paper that she also cowrote is asking a bit much. I'm not accusing Dr Lean of any sort of impropriety, but out in the big, bad outside world, this is called "Conflict of Interest". Big time.

 

More later but it's 2 AM and I'm buggered.

 

To answer your final question, I guess you are about right although I would have some reservations about the confidence with which predictions are offered. Put another way. If the temps in the MWP were roughly the same as today and the temps in the LIA were about a degree cooler and if the change between these two states was caused by a change in natural forcings of only .6 W/M-2, then I would expect the rise of 2.4 W/M-2 since the LIA to cause problems.

 

If you get 1/2 an hour, this is an interesting talk by Bob Carter showing the context of modern warming.

 

BTW, how much Anthropology have you read? There's an idea that's been buzzing around and I need an anthropologist to kick it to pieces. (Or to tell me it's been thought of, whatever. )

Edited July 5, 2011 by JohnB

[Neph70]

Climate change is most certainly occurring, however the levels of human based interference seems to be what is posing the greatest debate(s) from my understanding.

 

What has not been addressed in these arguments however are the levels of interference from our localised solar system region and deep space anomalies affecting our regional area of space:

 

Thus I present the interview with Ian Plimer Author of Heaven and Earth and professor of Geo-engineering and Mining from Sth Australia University.

 

These questions are posed with some very interesting answers:

[JohnB]

Welcome to SFN, Neph70.

 

Where was that interviewer from? I mean asking about Nibiru? I'm certain Plimer was thinking "What is this idiot talking about?"

 

Just by the by, we aren't too big on self promotion here and posting your own video in your first post looks a bit sussed.

 

Cheers.

[Neph70]

Hey thanks JohnB for the kind welcome.

 

Yes indeed it is my own video and I am not trying to promote it or myself being a layperson in this regard I hold no scientific background and nor do I claim to be. I did however have some valid questions that Professor Plimer seemed to enjoy answering.

 

My post was not meant to achieve anything but to merely add to the scientific data in this discussion as the galactic region of space is a new field of research and not often discussed in tandem with Climate models or global weather anomalies.

 

The suns influence on galactic climate models is more often talked about yet has been largely ignored in Australia where I am from since the Governments introduction of the Carbon Tax.

 

I had hoped this video would assist posters in reaching a more balanced view of global warming as galactic warming is taking place synchronously.

Thanks so much again for your welcome. =0)

 

Oh as far as the Nibiru question,.... there has been a lot of scientific frauds recently give predictive dates for global catastrophe. I purely wanted to expose these as the wafflings of an overactive imagination. Professor Plimer indeed concurred.

 

[WorldOfBiochemistry]

I am not a skeptic, but I agree that there are many bad information that sometimes highlights things that does not deserve to be highlighted. Nevertheless, the weather is changing and would change even in the absence of mankind. We are just accelerating the process...