Jump to content


Photo
* - - - - 1 votes

Who here is a global warming skeptic?


  • Please log in to reply
227 replies to this topic

#21 JohnB

JohnB

    Hello? Is this thing on?

  • Senior Members
  • 2,811 posts
  • LocationBrisbane. Oz.

Posted 23 June 2011 - 12:40 PM

swansont, to be fair I don't think the whole "global cooling thing of the 70s is quite cut and dried. It was certainly popularised by Newsweek and other publications. (I remember reading the dire predictions in my morning paper, the Saturday "Science" section.) However both Drs Schneider and Erlich were quite happy to be interviewed on the topic which must have given the idea credence in the public mind. It's also unlikely that they were publishing papers about "warming" while giving interviews about "cooling".

Similarly the CIA seems to have had no problems in assembling a panel to advise them of possible problems due to a cooling climate.

I think that the fairest thing that could be said about the cooling hype is that there were some climatologists who were indeed concerned about cooling and they publicised those concerns. However there was at that time no consensus concerning cooling or warming. But it cannot be written off as "media hype" alone.

As usual the truth lies between the extremes of "Scientists were warning of cooling" and "It was just a media thing".

I do find it interesting that two of the warners about the dire consequences of cooling became leading lights warning about the dire consequences of warming. I guess some people just can't find a potential disaster that they don't like. ;)
  • 0
There are two rules for being successful in life.
1. Never tell everything you know.

#22 swansont

swansont

    Shaken, not stirred

  • Moderators
  • 25,550 posts
  • LocationWashington DC region

Posted 23 June 2011 - 01:12 PM

swansont, to be fair I don't think the whole "global cooling thing of the 70s is quite cut and dried. It was certainly popularised by Newsweek and other publications. (I remember reading the dire predictions in my morning paper, the Saturday "Science" section.) However both Drs Schneider and Erlich were quite happy to be interviewed on the topic which must have given the idea credence in the public mind. It's also unlikely that they were publishing papers about "warming" while giving interviews about "cooling".

Similarly the CIA seems to have had no problems in assembling a panel to advise them of possible problems due to a cooling climate.

I think that the fairest thing that could be said about the cooling hype is that there were some climatologists who were indeed concerned about cooling and they publicised those concerns. However there was at that time no consensus concerning cooling or warming. But it cannot be written off as "media hype" alone.

As usual the truth lies between the extremes of "Scientists were warning of cooling" and "It was just a media thing".

I do find it interesting that two of the warners about the dire consequences of cooling became leading lights warning about the dire consequences of warming. I guess some people just can't find a potential disaster that they don't like. ;)


Then it should be no problem finding the actual peer-reviewed papers. But everybody cites Newsweek.

The NAS report, cited in the article, is a far cry from a panicked prediction of an imminent ice age

http://www.wmconnoll...e/nas-1975.html
http://logicalscienc...eks-global.html

Unfortunately, we do not have a good quantitative understanding of our climate machine and what determines it's course. Without this fundamental understanding, it does not seem possible to predict climate-neither in short-term variations nor in any in its larger long-term changes.


They were saying we don't know enough to make predictions.

Now, of course we know more, based on 35 more years of data and models.
  • 0

Minutus cantorum, minutus balorum, minutus carborata descendum pantorum                                   To shake my vodka martini, click the up arrow ^

I am not a minimum-wage government shill

My SFN blog: Swans on Tea                                                           

 

 

                                                                                                                     

 

 


#23 John Cuthber

John Cuthber

    Chemistry Expert

  • Resident Experts
  • 8,891 posts
  • LocationEngland

Posted 23 June 2011 - 01:35 PM

To be fair, though I'm solidly convinced of AGW, I remember that back in the 70s there were really articles and even adverts about the "coming ice age" in things like Scientific American. (I know that's not much more peer reviewed than Newsweek)
So what?
That was then, this is now.

This proves that science is not dogma; nothing else.

They made a prediction based on the data available at the time ( the records of ice ages) and the prediction was that, since there had been ice ages in the past, there would be others in the future.
That's not an unreasonable prediction.
The press probably blew it out of proportion because that's what sells papers. What else would they have done?

Since then those studying the climate have done another 40 years of work on the issue and have found another major factor- the greenhouse effect.

They now include that effect in their models.
The improved models now show, at least in the relatively short term, a different behaviour.
There may well be another ice age on the way, but before that there will be warming which won't make things better for our species and that warming is essentially down to us.

What I don't understand is why those who don't accept AGW keep banging on about something which is very old news. Is it the best they can come up with?

It reminds me of the story of the old schoolteacher musing on the fact that a lot of his students had failed exams because they didn't remember something which turned out not to be true anyway.

Edited by John Cuthber, 23 June 2011 - 01:36 PM.

  • 0
What's this signature thingy then? Did you know Santa only brings presents to people who click the + sign? -->

#24 mississippichem

mississippichem

    fluorescent protein

  • Resident Experts
  • 1,678 posts
  • LocationMS, USA

Posted 23 June 2011 - 01:35 PM

Then it should be no problem finding the actual peer-reviewed papers. But everybody cites Newsweek.


This isn't something I know much about but here is a PDF that you guys should find interesting.

http://aerosol.ucsd....08-myth1970.pdf

It has a list of "global cooling" and "global warming" papers from 1965 to 1975 with numbers of citations; no idea if the list is exhaustive. It appears that there was in fact some peer reviewed literature that embraced "global cooling" at the time. However they seem to be outnumbered and out-cited by the global warming papers in significant numbers.

It appears that JohnB and you, swansont, are both correct in a way.

Edited by mississippichem, 23 June 2011 - 01:36 PM.

  • 1
You've come a long way. Remember back when we defined what a velocity meant? Now we are talking about an antisymmetric tensor of second rank in four dimensions.

-Feynman Lectures on Physics II


#25 Marat

Marat

    Quark

  • Senior Members
  • 1,700 posts

Posted 23 June 2011 - 06:18 PM

Another problem with the modern climate change consensus is the supposedly imminent swamping of the island nation of Tuvalu. This tiny island in the South Pacific is just about at sea level, and in the 1970s a guage was installed on the ocean bed near it to determine when it would start to be covered by the rising seas as an inevitable result of the melting of ice associated with global warming. Since the guage failed to cooperate, however, it was replaced with another more recently in a different place to disguise the failure of the predicted results, and Tuvalu remains an intact land mass. But melting water has to go somewhere!

I don't pretend to be a climate scientist or anything close to it, but I am concerned at what appears to be the politicization of science with respect to this issue. The whole 'Gaia' movement which regards humanity as a toxic parasite on the Sacred Mother Earth which is much more important to preserve, even at the cost of extinguishing that parasite; the whole movement of environmental trogdolites who would like nothing better than to have an excuse to dismantle the industrial and scientific world so that we could all return to the Rousseauian paradise of living in a cave with a candle while enjoying the fresh, clean air and the trickling streams; and the aggressively naturist Green Peace and animal rights movements all seem to inject an irrational, messianic, religious aspect into the climate change debate which threatens to silence critics rather than to accord them the fair hearing that Popperian falsifiability standards normally allow in science.

Science and politics often get mixed in deleterious ways, even in the modern world, as the examples of Lysenko and the Nazi theory of 'blood purity' suggest. There was a very serious international congress on maintaining the purity of the blood in Germany in 1936, which was interpreted, not as avoiding septicemia, but as ensuring racial purity, which is a form of reasoning essentially based just on a pun -- but still, Ph.D.s and M.D.s were seriously arguing this nonsense. The general problem with science is that it is often internally perfectly accurate in its methods, but the entire theory is based on a suppressed and false premise.

There is so much at stake in this debate that any hint of political irrationality in the science backing it up should encourage everyone to be a climate sceptic. Given the current design of our political institutions, the multi-trillion dollar cost 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, with catastrophic impacts on life expectancy, health, mental illness, alcoholism, crime, unemployment, and economic growth stagnation. People forget that even with the most efficient operation possible of our existing carbon-based economy, recessions and depressions still occur, and most Western nations have an unemployment rate of around 10%, plus massive debts. What is going to happen if we now deliberately burden these economies with the hugely-expensive transition to a green economy? The surplus wealth generated by the uninterrupted operation of the carbon-based economy is a prerequisite to finding cures for cancer, diabetes, renal disease, lupus, atherosclerosis, etc., so you can forget ever seeing any of that for yourself or your great-grandchildren if a drastic transition to a green economy soaks up all our resources.
  • 0

#26 swansont

swansont

    Shaken, not stirred

  • Moderators
  • 25,550 posts
  • LocationWashington DC region

Posted 23 June 2011 - 08:16 PM

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.
  • 0

Minutus cantorum, minutus balorum, minutus carborata descendum pantorum                                   To shake my vodka martini, click the up arrow ^

I am not a minimum-wage government shill

My SFN blog: Swans on Tea                                                           

 

 

                                                                                                                     

 

 


#27 mooeypoo

mooeypoo

    Oh look, Pwnies!

  • Moderators
  • 5,699 posts
  • LocationNoo Yoak

Posted 23 June 2011 - 08:32 PM

!

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.


  • 0

If I was helpful, let me know by clicking the [up arrow] sign ^^

No trees were harmed in the creation of this post.
But billions of electrons, photons, and electromagnetic waves were terribly inconvenienced during its transmission.

 

Adventures in Algorithms http://moriel.smarterthanthat.com

Advocating Science http://smarterthanthat.com


#28 Essay

Essay

    Atom

  • Senior Members
  • 294 posts
  • LocationColorado State University

Posted 23 June 2011 - 08:41 PM

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.

~
  • 0
Fire oxidizes carbon; Pyrolysis reduces carbon.
It's time for the next step in our evolutionary symbiosis with fire
--in order to manage our domain everlastingly.

#29 JohnB

JohnB

    Hello? Is this thing on?

  • Senior Members
  • 2,811 posts
  • LocationBrisbane. Oz.

Posted 24 June 2011 - 08:37 AM

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 by JohnB, 24 June 2011 - 10:05 AM.

  • 0
There are two rules for being successful in life.
1. Never tell everything you know.

#30 swansont

swansont

    Shaken, not stirred

  • Moderators
  • 25,550 posts
  • LocationWashington DC region

Posted 24 June 2011 - 10:26 AM

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.
  • 0

Minutus cantorum, minutus balorum, minutus carborata descendum pantorum                                   To shake my vodka martini, click the up arrow ^

I am not a minimum-wage government shill

My SFN blog: Swans on Tea                                                           

 

 

                                                                                                                     

 

 


#31 JohnB

JohnB

    Hello? Is this thing on?

  • Senior Members
  • 2,811 posts
  • LocationBrisbane. Oz.

Posted 24 June 2011 - 12:50 PM

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. :) )
  • 0
There are two rules for being successful in life.
1. Never tell everything you know.

#32 Essay

Essay

    Atom

  • Senior Members
  • 294 posts
  • LocationColorado State University

Posted 24 June 2011 - 07:28 PM

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)."

Posted Image

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."

~
  • 0
Fire oxidizes carbon; Pyrolysis reduces carbon.
It's time for the next step in our evolutionary symbiosis with fire
--in order to manage our domain everlastingly.

#33 Marat

Marat

    Quark

  • Senior Members
  • 1,700 posts

Posted 24 June 2011 - 11:57 PM

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.
  • 0

#34 JohnB

JohnB

    Hello? Is this thing on?

  • Senior Members
  • 2,811 posts
  • LocationBrisbane. Oz.

Posted 26 June 2011 - 01:32 AM

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. :D
  • 0
There are two rules for being successful in life.
1. Never tell everything you know.

#35 Essay

Essay

    Atom

  • Senior Members
  • 294 posts
  • LocationColorado State University

Posted 26 June 2011 - 06:40 AM

...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 by Essay, 26 June 2011 - 07:13 AM.

  • 0
Fire oxidizes carbon; Pyrolysis reduces carbon.
It's time for the next step in our evolutionary symbiosis with fire
--in order to manage our domain everlastingly.

#36 Marat

Marat

    Quark

  • Senior Members
  • 1,700 posts

Posted 26 June 2011 - 02:50 PM

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.
  • 0

#37 JohnB

JohnB

    Hello? Is this thing on?

  • Senior Members
  • 2,811 posts
  • LocationBrisbane. Oz.

Posted 26 June 2011 - 03:19 PM

~Points and laughs....

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

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 by JohnB, 26 June 2011 - 03:21 PM.

  • 0
There are two rules for being successful in life.
1. Never tell everything you know.

#38 Essay

Essay

    Atom

  • Senior Members
  • 294 posts
  • LocationColorado State University

Posted 27 June 2011 - 07:13 PM

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 :)
  • 0
Fire oxidizes carbon; Pyrolysis reduces carbon.
It's time for the next step in our evolutionary symbiosis with fire
--in order to manage our domain everlastingly.

#39 JohnB

JohnB

    Hello? Is this thing on?

  • Senior Members
  • 2,811 posts
  • LocationBrisbane. Oz.

Posted 28 June 2011 - 02:27 AM

I hope lunch was enjoyable. :D

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. :D

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. :D ) 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.


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 by JohnB, 28 June 2011 - 02:29 AM.

  • 0
There are two rules for being successful in life.
1. Never tell everything you know.

#40 Essay

Essay

    Atom

  • Senior Members
  • 294 posts
  • LocationColorado State University

Posted 28 June 2011 - 06:40 PM

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. :D ) 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
  • 0
Fire oxidizes carbon; Pyrolysis reduces carbon.
It's time for the next step in our evolutionary symbiosis with fire
--in order to manage our domain everlastingly.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users