2010-09-08 09:43:21BASIC rebuttal #125: Positive feedback means runaway warming: SEE REVISION 1 at 11 Sep 2010, 9:47 AM
nealjking

nealjking@gmail...
91.33.122.182

What the science says...

Positive feedback means that a system reacts to a stimulus by reinforcing that stimulus, so the stimulus builds up, and the output builds up, and the stimulus builds up... However, this only leads to a "runaway" instability if the reinforcement is strong enough. If it's not, as in the case with the enhanced greenhouse effect, the feedback can give rise to a definite, but stable, increase over the original stimulus.


One of the problems about understanding the extent of global warming (the question of climate sensitivity) is that the total average temperature increase due to CO2 is greater than the first guess: Climatologists must also take into account "second-order" effects which add to the initial estimate of the warming. It is not easy to calculate these effects, but the general consensus is that, overall, they magnify the temperature increase by about a factor of 3. These second-order effects work as a form of "positive feedback."

An example of this: Imagine the pre-industrial world, with the Earth, land & sea, in rough thermal balance. Then add a dollop of 35% more CO2 to the atmosphere (by burning fossil fuels): Due to the enhanced greenhouse effect (EGE), the radiation of infrared energy is inhibited, and this reduction in radiative cooling raises the global average temperature. But the increase in temperature has the effect of increasing even further the amount of atmospheric CO2, because the heated ocean will hold less CO2 (think of a can of warmed Coke), and the warming Arctic tundra will reveal formerly frozen biomass that will decompose and release more CO2. So you get even more CO2 in the atmosphere, which gives rise to even more warming, which gives rise to even more CO2...

But this is where the suspicions of the skeptics are aroused: "If more CO2 gives rise to higher temperature, and higher temperature gives rise to more CO2, and this additional CO2 gives rise to even higher temperature, doesn't this go on forever? Doesn't that mean that the Earth would turn into an oven? If the greenhouse effect REALLY has positive feedback, why hasn't this happened already? Something is wrong with this picture!"

This line of thought is partly right and partly wrong:

  1. The cycle does go on forever, like the reflections between two facing mirrors; but
  2. At each step in the cycle, the incremental increase gets smaller and smaller. After a few cycles, the increase is negligible.

 

Why doesn't the enhanced greenhouse effect run away?

The plot below shows how the temperature increases due to the enhanced greenhouse effect (EGE), through the feedback cycles. (This plot has been generated from a simplified model for the EGE warming.)



In these plots, we tried three different values of the feedback parameter, f:

- Due to the feedback, the temperature does indeed rise beyond the initial jump (due to the dollop of 35% more CO2).

- However, after several (3 to 10) iterations, there is no further significant change.

- The terminal value of the temperature increase depends on the value of the feedback parameter f: The stronger the feedback, the larger the terminal value. But no matter how large f is, the system always stabilizes.

 

CONCLUSIONS

- When you add CO2 to this model system, there is indeed positive feedback, so even more CO2 will end up in the atmosphere than you dumped in from the burning of fossil fuels.

- However, this does not give rise to a runaway scenario: Eventually, the impact of that dollop of CO2 comes to an end.

- Now, in the real world, that end will not be an ultimate end until we stop adding more CO2 ourselves: Every time we add another dollop of CO2 through the burning of fossil fuels, we kick off another round of significant feedback cycles. Currently, we are still adding small dollops all the time...

 

Note:  A more detailed explanation is provided here.

2010-09-08 09:49:27The Basic version is derived from the Advanced version
nealjking

nealjking@gmail...
91.33.122.182

- Yes, I know: The link back to the Advanced version is broken. John, maybe you can fix it.

- I've tried to bring this down to the minimal level possible. But it might still be at an Intermediate level. 

2010-09-08 11:30:31Fixed the link
John Cook

john@skepticalscience...
121.222.93.62

I've fixed the link to the Advanced rebuttal. Note for authors posting hyperlinks. The way you do it is to highlight the text then click the link icon (the chain) then paste the URL into the Link URL field.

Feedback on the basic rebuttal - yes, I'd say this is at an intermediate level. For the basic level, I think you could leave out figure 1 and the discussion of 'gain'. All the average person needs to know is the general concept of feedback, not the more nitty gritty details.

A question about your methodology - is there a feedback value f for which you get runaway feedback with your model? I think it would be good to show this in the graph - to show that it is possible to have runaway feedback but only if the feedback is high enough.

2010-09-08 17:45:50Feedback on feedback
nealjking

nealjking@gmail...
84.151.34.204

John,

- Let's see if there are more comments; then I can re-post this piece in the Intermediate list, and make a revision in this Basic list to excise Figure 1.

- For the logarithmic model of Figure 2, with dC' = f*dC/C (equation not shown in this non-Advanced version), you can crank f up as high as you like, but it will never run away. It still stabilizes. The terminal value gets really high, but it plateaus. In this way, it is completely unlike the linear amplification model of Figure , for which the fate of the system depends on whether the gain factor is >, =, or < the critical value of 1. I think you are still mulling over the original remark by Ned on the different amounts of feedback. Perhaps he had a different model in mind; but in this logarithmic model, there is no threshold value for f that gates a behavioral difference. With some head-scratching, I could possibly gin one up, but it will take some contrivance, I think.

UPDATE: I changed some wording in the text, that probably misled you to thinking that a larger value of f would cause instability. This was a nod to Ned's original comment; but I think it's inappropriate now.

2010-09-09 01:19:18
doug_bostrom

dbostrom@clearwire...
184.77.83.151

This is indeed hard to explain in a simplified way.

"The plot below shows how the CO2 concentration increases due to the EGE, through the feedback cycles." -->  The plot below shows how the CO2 concentration increases due to the EGE (enhanced greenhouse effect), through the feedback cycles."

 

Worth mentioning, the planet radiates at an exponentially greater rate as temperature increases. Might refer to Venus as a worst-case scenario; Venus' surface temperature is limited by radiation at the top of atmosphere. 

-More- complication but after all without taking radiation into account even the atmosphere we enjoyed prior to the current unpleasantness would have resulted in ever-increasing temperatures. 

2010-09-09 03:54:42
nealjking

nealjking@gmail...
84.151.34.204

doug_bostrom:

- EGE: If I can't rely on this being understood a few lines after defining it, I won't rely on it at all. I'll just leave it in, like a vitamin pill, to allow the reader to get used to the acronym.

- "the planet radiates at exponentially greater rate": Exponentially in what variable? The Stefan-Boltzmann integral over all frequencies for a blackbody goes like T4,  but this is not directly relevant, since the EGE works on frequency windows.

- The EGE is based on radiative transfer. How does bringing Venus into the picture clarify the message?

 

2010-09-09 04:08:04
doug_bostrom

dbostrom@clearwire...
184.77.83.151

Sorry, Neal, I =thought= I'd scrutinized your writeup for an introduction of "EGE" but missed it. 

"The EGE is based on radiative transfer. "

Yes, but you don't mention radiation.  

I honestly think a lot of people freshly approaching this topic will not have any notion of radiative equilibrium. As equilibrium is what actually arrests ever-increasing temperature of the planet, it's probably worth explicitly mentioning. Once that is introduced, it's a short step to explaining that radiation becomes more efficient as a heat dumping mechanism as temperature increases, thus making a boundless "runaway" effect impossible quite apart from the more subtle mechanism you've explained.  

2010-09-09 05:24:46
nealjking

nealjking@gmail...
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doug_bostrom,

I have added a few words of explanation on the EGE and radiation, at the top.

But actually,  the reason the EGE works is that the atmosphere becomes LESS efficient at releasing heat with additional CO2, because the effective radiating temperature (for the IR band of interest) decreases. If the EGE created too much positive feedback, and the planet got red-hot, the T4 radiative power would be of interest; but that is also true of any positive-feedback system. The previously cited sound system is ultimately limited by the power it can draw from the plug; and probably by several other power bottlenecks in its construction. Nevertheless, these constraints don't act soon enough to they prevent the classic positive-feedback shriek.

The point I want to make about the EGE is that there is "no shriek": the behavior of the system is self-limiting without taking extra constraints into account. The argument that is being countered is, "If the EGE really has positive feedback (which is why you guys claim that the temperature increase is 3 deg-C instead of 1 deg-C), why doesn't the Earth go to a zillion degrees?" And the answer is, "Because positive-feedback systems aren't forced to do that: They can also quit at a certain point. It depends on the details of the physics."

It's kind of a subtle point. I'm not completely sure that the concept of a Basic-level explanation really makes sense: Someone who can understand the math should probably read the Intermediate or Advanced explanation (it will be more logical); and it's not clear that someone who cannot understand the math will appreciate the question, to begin with.

 

2010-09-09 05:44:20
doug_bostrom

dbostrom@clearwire...
184.77.83.151

I get what you're saying, Neal.  As you say, net radiation is limited by the input power to the system. I appear to be operating in a deeper fog than I'd imagined. :-) 

Using my present funk to advantage, what I'm not getting from this explanation is how the feedback parameter is derived. That may come down to the mirror analogy being not quite apt or perhaps not developed fully. I think of two mirrors facing one another and what springs to mind is loss of energy.

Perhaps you should refer to some specific physical mechanisms to explain the feedback parameter, be a little less abstract? 

 

2010-09-09 05:56:44
nealjking

nealjking@gmail...
84.151.34.204
The actual mechanism of the enhanced greenhouse effect is one of the most subtle aspects of climate change theory. It doesn't rely on the vast organization of data that other areas do, but there are a whole lot of intricate ideas that are linked together.
2010-09-09 16:48:53Comment
John Cook

john@skepticalscience...
121.222.93.62

I'm sorry Neal, I must confess, I am still a little hung up on Ned's initial graphs demonstrating the possible responses to positive feedback:

Your post does demonstrate the basic principle that positive feedback doesn't have to lead to a runaway effect - whether that effect be on temperature or CO2 levels. So while doesn't address the issue of runaway warming directly, it does demonstrate the principle of "diminishing returns" for positive feedback.

However, I wonder whether shows the response of CO2 to temperature change is complicating it unnecessarily. People might be confused that your graph shows CO2 concentration - weren't we talking about runaway warming? Wouldn't it be more direct to show temperature response to feedback?

In fact, couldn't this principle be demonstrated without invoking the greenhouse effect at all. All we're wanting to show is that in a system with net positive feedback, it doesn't necessarily lead to runaway warming. So temperature and feedback are the only two variables that need to be considered to make the point. The other details can be hashed out in the higher levels.

Sorry to be a pain about this. If everyone thinks I'm being too anal, please set me straight!

2010-09-09 18:36:53reply to comment
nealjking

nealjking@gmail...
91.33.118.20

- I don't know where Ned gets these graphs from: all I can say is that it's not clear to me what kind of dynamical equations would give rise to this kind of alternative behaviors (rapid increase vs. plateau) on the basis of a strength parameter: If you want to adjust an exponent, you can easily compare x(1.2) to x(0.5), but you don't normally find systems coupled through an adjustable exponent.

- If we choose, we could emphasize the dT behavior instead of the CO2 behavior: They are proportional anyway (dC' = e * dT). But if we're talking about the EGE, we can't leave out the role of CO2 in the story: that's an essential part of the dynamics that create the feedback.

- In principle, we could drop the connection to the EGE: Logically, it's not strictly necessary, and in the Advanced presentation I'm careful to state that this is a demonstration of the PRINCIPLE that a system can have positive feedback without blowing-up behavior; it is only a bit interesting that a toy model that is built out of the simplest ingredients of known EGE dynamics displays this advertised behavior. However, when it comes to the Basic presentation, I'm leaning more on the idea that this is a reasonable way of presenting how the atmosphere works: and I think that is fair enough, at this level of sophistication. Although far from exact, it kind of behaves the way you would expect a full model to behave. But at the Basic level, if we just present it as a demonstration in principle, I think it loses its appeal in terms of relevancy: Why should such a reader, whom we are assuming is not motivated to study the more mathematical treatment in the Advanced version, find any interest in some mathematical model to demonstrate some abstract principle?

Bottom line:

- At the Advanced level, I think the message is: "The EGE can have positive feedback without blowing up. Here is a toy model that does that. By the way, it has some mathematical similarities to what we know of EGE."

- At the Basic level, I think the message should be: "The EGE can have positive feedback without having to blow up. It kind of goes like this ..."

 - If you like, we can modify the text to indicate we're plotting temperature increase instead of CO2: the plots don't need to be changed.

 

Neal

2010-09-09 19:57:59
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.155.213
Neal, I agree with John, that there will be no runaway warming is the essential point. The rebuttal as it stands seems a bit advanced for the basic level. In concluding the rebuttal it may be worth drawing attention to examples in the paleo record to counter the argument, the inter glacial's for instance, when CO2 was acting as a feedback - no runaway warming then either. 
2010-09-09 20:28:36
nealjking

nealjking@gmail...
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Dappledwater,

I think you are missing the argument that is being rebutted.

Nobody on either side is suggesting that there has been runaway global warming, there's no need to cite evidence.

The point is that some people have incorrectly thought that, since climatologists claim that positive feedback is increasing the expected warming from 1 deg-C to 3 deg-C, that these climatologists must be wrong. And their argument has been, "If there were any positive feedback, the temperature would have gone through the roof the last time we had extra CO2 That didn't happen; so this positive feedback idea is all wet, it can't apply to GW. Stop predicting 3 deg-C, and go back to 1 deg-C, you alarmists!"

So the points that have to be made are:

- It IS possible to have a positive-feedback system that does not go through the roof; and

- The Earth's atmosphere, with respect to the enhanced greenhouse effect, IS such a system.

 

2010-09-09 21:22:32
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.155.213

Neal,

"Basic rebuttal #125 - Positive feedback means runaway warming". 

You seem to be too generous, clearly someone on the skeptic side has claimed exactly what you suggest they haven't. As for providing evidence, it demonstrates that we already have a positive feedback system in place that does not go through the roof - and is  also pertinent to this in your rebuttal: "Doesn't that mean the Earth would turn into an oven?. Why hasn't this happened already."

Just constructive (I hope) input from a non expert.

  

 

 

 

 


 

 

2010-09-09 21:43:46
nealjking

nealjking@gmail...
91.33.118.20

Dappledwater,

The only ones that have claimed a runaway greenhouse effect are, embarassingly enough, Stephen Hawking and James Lovelock - who are not denialists. Their errors have been pointed out. But odd as these examples are, I am not going to waste time trying to instruct these two individuals. I guess it proves that there IS such a thing as being overly specialized.

If you think about it, it wouldn't make sense for a denialist to proclaim the reality of a runaway greenhouse effect: He would have to conclude that the "Warmists" are not worried enough! I've never heard of a denialist standing on a soapbox and proclaiming, "Al Gore is an optimist! Down with Al Gore!"

 

2010-09-10 06:10:04Rebuttals to 125: runaway warming
jimalakirti

jimalakirti@gmail...
71.34.142.115

I posted an edited version of the Advanced Version early this morning (Mountain Savings Time) as I think someone asked me to do. I apparently got there too late.

Sorry.

2010-09-10 07:44:29Improvements from the Advanced version
nealjking

nealjking@gmail...
91.33.118.20

have been propagated into this version as well.

Thanks, jimalakirti, John, Dappledwater, and doug_bostrom.

By the way, I realize that I never answered one of doug_bostrom's questions above, concerning the nature of the feedback parameter:

The basic point is explained earlier in the article:

"An example of this: Imagine the pre-industrial world, with the Earth, land & sea, in rough thermal balance. Then add a dollop of 35% more CO2 to the atmosphere (by burning fossil fuels): Due to the enhanced greenhouse effect (EGE), the radiation of infrared energy is inhibited, and this reduction in radiative cooling raises the global average temperature. But the increase in temperature has the effect of increasing even further the amount of atmospheric CO2, because the heated ocean will hold less CO2 (think of a can of warmed Coke), and the warming Arctic tundra will reveal formerly frozen biomass that will decompose and release more CO2. So you get even more CO2 in the atmosphere, which gives rise to even more warming, which gives rise to even more CO2... "

If you want to see the math, you should go to the Advanced presentation.

2010-09-10 12:10:33
Nicholas Berini

nberini@gmail...
68.193.36.249

Are we still trying to do a basic version??

This is college reading (intermediate/advanced) - my little brother would nod his head but not compute (freshman environmental studies): 

"Positive feedback means that a system reacts to a stimulus by reinforcing that stimulus, so the stimulus builds up, and the output builds up, and the stimulus builds up... However, this only leads to a "runaway" instability if the reinforcement is strong enough. If it's not, as in the case with the enhanced greenhouse effect, the feedback can give rise to a definite, but stable, increase over the original stimulus."

This is more on his level:

"Some skeptics ask, if the concept of 'positive feedbacks' is true, why don't we have runaway warming?  

A positive feedback is a response to a change that tends to amplify that change. For example; when the earth heats, the polar ice caps melt. These ice caps reflect more light than ocean water (light colors reflect heat, dark colors absorb it).  Now, because less light is being reflected back to space, more is being absorbed and thus the warming is increased.  However, these feedbacks have diminishing returns. The cycle does go on forever, like the reflections between two facing mirrors; but at each step in the cycle, the incremental increase gets smaller and smaller. After a few cycles, the increase is negligible.

Then maybe point out the irony of skeptics pointing to the paleoclimate as a reason there are not positive feedbacks but in fact the paleoclimate record is actually evidence for positive feedbacks. 

 

This is more on his level and he is far more interested and aware than the average person.

  

2010-09-10 19:14:16
nealjking

nealjking@gmail...
91.33.124.196

Nicholas Berini,

I'm open to moderating the language and "picking up the pace."

I'm not sure that I want to bring in the palaeoclimate issue: In my view, that opens up a whole different line of discussion & reasoning that could distract from the basic point being made.

I'll let this simmer for another day or so, to get a little distance from it. In the meantime, further comments and suggestions are welcome; improvements will ultimately be propagated to the other versions, if appropriate.

2010-09-11 07:33:38BASIC rebuttal #125: Positive feedback means runaway warming : Thumbs up
jimalakirti

jimalakirti@gmail...
71.34.142.115
Very good. short, concise, clear.
2010-09-11 09:47:44REVISION 1
nealjking

nealjking@gmail...
91.33.124.196

Some skeptics ask, "If global warming has a positive feedback effect, then why don't we have runaway warming? The Earth has had high CO2 levels before: Why didn't it turn into an oven at that time?"

What the science says...

Positive feedback for global-warming dynamics is not expected to lead to a runaway temperature blowout, because the diminishing returns on the feedback cycles will limit the amplification. The best estimate is that the overall result will be about a factor of 3.


Positive feedback happens when the response to some change amplifies that change. For example: The Earth heats up, and some of the sea ice near the poles melts. Now bare water is exposed to the sun's rays, and absorbs more light than did the previous ice cover; so the planet heats up a little more.

Another mechanism for positive feedback: Atmospheric CO2 increases (due to burning of fossil fuels), so the enhanced greenhouse effect heats up the planet. The heating "bakes out" CO2 from the oceans and arctic tundras, so more CO2 is released.

In both of these cases, the "effect" reinforces the "cause", which will increase the "effect", which will reinforce the "cause"... So won't this spin out of control? The answer is, No, it will not, because each subsequent stage of reinforcement & increase will be weaker and weaker. The feedback cycles will go on and on, but there will be a diminishing of returns, so that after just a few cycles, it won't matter anymore.

The plot below shows how the temperature increases, when started off by an initial dollop of CO2, followed by many cycles of feedback. We've plotted this with three values of the strength of the feedback, and you can see that in each case, the temperature levels off after several rounds. 


So the climatologists are not crazy to say that the positive feedback in the global-warming dynamic can lead to a factor of 3 in the final increase of temperature: That can be true, even though this feedback wasn't able to cook the Earth during previous periods of high CO2.

Note: A more detailed explanation is provided here.

2010-09-11 10:06:12The first Revision is just above
nealjking

nealjking@gmail...
91.33.124.196

Based on some suggestions by Nicholas Berini, I have shortened and picked up the pace on this Basic presentation.

I still have the graph, although that could go, too, if people don't think it helps.

 

Neal

2010-09-12 08:58:02
Nicholas Berini

nberini@gmail...
68.193.36.249
I like the new version and the graph.  
2010-09-12 09:02:59good job
dana1981
Dana Nuccitelli
dana1981@yahoo...
71.137.148.215
I like it, and agree on keeping the graph.
2010-09-12 18:04:16Qualification
gpwayne
Graham Wayne
graham@gpwayne...
86.158.204.104

Hi Neal - I think the latest version is very close, but this statement is too unequivocal:

"Positive feedback for global-warming dynamics can never lead to a runaway temperature blowout, because the diminishing returns on the feedback cycles will limit the amplification to about a factor of 3".

That's an estimate, surely? i think we need to make the speculative nature clear, rather than state it as fact.

2010-09-12 18:25:27
nealjking

nealjking@gmail...
84.151.43.165

gpwayne,

What about the following:

"Positive feedback for global-warming dynamics can never lead to a runaway temperature blowout, because the diminishing returns on the feedback cycles will limit the amplification. The best estimate is that the overall result will be a factor of 3."

2010-09-12 20:47:46
Riccardo

riccardoreitano@tiscali...
93.147.82.100
Runaway warming is in principle possible, even on earth or example). It's unlikely and it requires very long time, but we cannot say that it never leads to a temperatur blowout. Your sentence is correct if you limit it to the current state and a foreseeable future.
2010-09-12 20:49:18sentence screwed up
Riccardo

riccardoreitano@tiscali...
93.147.82.100

my first sentence should read:

 Runaway warming is in principle possible, even on earth (see Hansen, f or example).

2010-09-12 21:42:28Runaway
nealjking

nealjking@gmail...
84.151.43.165

Riccardo,

See:

http://www.realclimate.org/index.php/archives/2008/03/venus-unveiled/

and search on "runaway".

I've made some change in the sentence, but I don't want to send people towards an unlikely corner-condition case when we're trying to calm them down.

Here's the new Intro:

What the science says...

Positive feedback for global-warming dynamics is not expected to lead to a runaway temperature blowout, because the diminishing returns on the feedback cycles will limit the amplification. The best estimate is that the overall result will be about a factor of 3.

 

2010-09-12 23:42:07That's fine
gpwayne
Graham Wayne
graham@gpwayne...
86.158.204.104
Yes Neal - that's all that's needed. Thumbs up from me
2010-09-13 00:14:51ok for me
Riccardo

riccardoreitano@tiscali...
93.147.82.100

Neal,

I'm not sure why you pointed me to that RealClimate post. Anyway, dropping the "can never lead to .." is good enough for me.

2010-09-13 04:43:14We're over the hurdle
nealjking

nealjking@gmail...
84.151.43.165

OK, got 5 green thumbs for this one!

There are also Intermediate and Advanced versions of this: Review of them is also welcomed.

Thanks,

Neal

 

P.S. Riccardo:  Some of the discussion at RealClimate describes how difficult it could be to get to a Venusian version of Earth.

 

2010-09-13 09:41:28Published
John Cook

john@skepticalscience...
121.222.93.62

Thanks Neal, for your very hard work and patience in grinding through all 3 rebuttals! I've put them all online at:

http://www.skepticalscience.com/positive-feedback-runaway-warming.htm

Note - I had to streamline your basic rebuttal to make it short enough to tweet. It's actually still about 20 characters too long so welcome thoughts on how to get it shorter.

The big question now is how do we roll out your rebuttals? Do we post the basic rebuttal as a blog post and at the bottom of the blog post, have a green box with links to the other 2 rebuttals? Or do we provide more meat and post the intermediate or advanced levels? Thoughts welcome.

2010-09-13 10:25:14Shortening
nealjking

nealjking@gmail...
84.151.43.165

John,

a) Shortening:

"Positive feedback isn't expected to lead to a runaway warming because diminishing returns on feedback cycles limit the amplification."

=>

"Positive feedback won't lead to runaway warming; diminishing returns on feedback cycles limit the amplification."

 

 b) Roll-out:

I suspect there's enough meat in the Basic presentation: I don't want to over-estimate the tolerance of our readers for math. So probably post the Basic, with a link to the Advanced one.

I like the Advanced and the Basic ones best: In fact, I've linked them both ways, because I could imagine a reader of the Advanced getting a bit lost and wanting a quick overview; and I can imagine a reader of the Basic feeling "more is going on than is shown" and wanting more detail. The Intermediate one is kind of a hybrid: I put in a link to the Advanced, but not to the Basic. I didn't link from the Advanced to the Intermediate, because all the math that is in the Intermediate is already in the Advanced, so someone who wants something simpler should just go to the Basic.

I guess it will still be possible for someone to find the Intermediate, from some sort of list?

Maybe it's worth sending a head's up to our fan for Advanced postings, Katie.

 

Neal

 

2010-09-13 10:57:45Basic for blog post
John Cook

john@skepticalscience...
121.222.93.62

Neal, I'll post the basic rebuttal as the blog post later today and include links to the higher levels in the customary green box.

Note: I've invited Kate to join us on the forum. The Intermediate is available on the rebuttal page - all 3 tabs are there at the top of the rebuttal.

2010-09-13 23:29:43Published
John Cook

john@skepticalscience...
121.222.93.62
Neal, I really like the clarity of your basic rebuttal. Makes it so clear, very well explained. Thanks so much for your great patience through this whole process. Am quite excited about getting to roll out 3 levels of the same rebuttal in the one go!
2010-09-13 23:55:06
nealjking

nealjking@gmail...
91.33.124.246

It's actually fun to build a strong case. I guess it is some consolation for not following my first plan of becoming a physics professor.

The next project is the "CO2 is a trace gas" issue: That will likely also be a 3-at-1-time release, because they'll actually be building on each other, so I won't be sure about the 1st until the 3rd is also pretty much ready. (But I'm expecting the 1st and 2nd to be comprehensible within their own terms, so far as they go. Just depends on how much of the story you want to hear.)

Have you heard anything from Moth Incarnate? I have one discussion, on shifting temperature zones, that is about ready for review; but we had agreed to build a series of articles on Ecological impacts of GW, as I mentioned somewhere in the Authors' pages (Anne-Marie was also involved), of which it would be a part. We exchanged some email and he sent me some useful articles, but nothing recently. I can't really polish it off until I have a perspective on the series.

In lieu of some guidance, the ecological articles I'm thinking about are:

- How much of a stress will GW be on the ecology? (Almost done.)

- Why should we care about species extinction? 

Do you have any specific "hot" skeptical arguments touching on these points? I am more interested in the ecological angle than the agricultural angle (which I believe has been addressed recently anyway).

My knowledge of biology is relatively sketchy, so I'd prefer to have some guidance and sanity-checking.

Neal