Global Warming... fact, fiction, or a little of both?

quote:

---

Heheheh... I agree. And thus the question becomes is GW consistent with a scenario where glaciers eat Manhattan? And I don't mean beyond 100+ years.

---

It would probably take much longer than 100 years to produce significant continental glaciers even if it started tomorrow.Also, the idea of GW ever causing an Ice Age doesn't seem to be a consensus view, since Science seems to have recently ran a refutation of it in their "Perspectives" column. I posted the summary in this thread. It'll be a little while longer till we all get free online access to the compete article.This message has been edited by gene90, 09-15-2005 11:31 AM

Let's keep in mind that I laid out specific points and have already stated that I do aree that there appears to be a warming trend, and I most certainly agree that humans have been pumping out CO2. Thus the more important points were the latter ones, though accurate answers to those first two, suggest something about the ultimate conclusions.So I was in agreement up till this point... Now I really want to move away from Crichton. I can only assume this means you did not read his book. He discusses regional versus global temp issues. Now maybe you did read it and missed it, or somehow read into that section some meaning it didn't have, but I'd rather not get derailed into discussing the book. The only thing I have to say is that if you have not read it, and this came from critics, this is the second patently false statement I have seen about his book from critics.He may very well have made mistakes, but as yet none that anyone has placed in his typewriter. Okay back on track, and sweet. I will be reviewing the data over the next couple of days. As this is recent data, I am wondering (if you know) whether it has been corroborated by others, and if so if it is from original data or simply using the same generated data. I think there still seem to be pieces missing. I get the correlation (there are rising temps and there are rising CO2 levels), specifically over the last few years, but not the causation... the connection.We've been pumping out CO2 (actually I'll switch to GHGs) for quite a while and yet the correlation was not consistent, and indeed was contrary for a portion of time. This can be explained (and has been) due to the nature of additional emissions, yet still leaves somewhat of a question mark. After subsidence ended the correlation picked back up and with a bit more rapid incline (so far). Is this increase in increase a significant product of GHGs, or is it more of a synergistic effect between a natural and mandmade source?I suppose what I'm bringing up is that nature itself can change temps and it can change relatively quickly. Is there a good way of measuring/separating natural and manmade components?From what I have been reading there is still no solid mechanical modeling of the atmosphere as it would be sans the human input, with some suggestion that it might actually be in a temporary warming trend (solar), beyond just the overall earthly warming cycle. But you may have better info.By the way this is the kind of stuff I was looking for. I take it you are involved in climatology or something like that?I will read your links. I should say I have already been perusing the realclimate site after viewing the Wiki link crash provided. I have to say I am feeling 50/50 about that site. Maybe I'm biased by the superiority of EvC. I did see some comments that were not quite right (its not like their was unanimity there either). I won't go into them, and focus to see if I see anything from the specific RC links you provided.Thanks.

---

holmes
"...what a fool believes he sees, no wise man has the power to reason away.."(D. Bros)

This is true. I have always felt that it is more the rate at which these changes are occurring that is of concern. The increases in atmospheric CO2 caused by anthropogenic emissions are occurring at a much faster rate than most of the processes which could potentially compensate for it (it's going to take several hundred years for the ocean to equilibrate, for example, and that's one of the faster ones). Given that, straight physics says the temperature has to increase. How much is the question, with the big uncertainty being the role of clouds, which both trap and reflect heat and therefore give modellers headaches.As to whether it is a good thing or not, that really depends on your perspective. Ironically, it is human civilisation that is most likely to suffer from our own excesses. Life - in some form or another - will most likely eventually adapt and survive (though again, the rate of change may place stress on most ecosystems - which have, after all, evolved to cope with current climatic conditions - and cause some degree of extinction).On a more general note, I've always been interested on where the burden of proof has been placed with regard to this issue. On it's own, increasing CO2 in the atmosphere will warm the planet. So people who deny a warming planet are effectively arguing that the increase we are instigating is completely compensated for by a complex climatic system which (as they themselves argue) we don't fully understand. As a hyperbolic analogy: imagine if a medical company found a cancer drug which was toxic on its own but claimed that it was all OK because the body safely broke it down. Would they need to prove it was safe, or would doctors have to prove it was harmful?

quote:

---

This is true. I have always felt that it is more the rate at which these changes are occurring that is of concern. The increases in atmospheric CO2 caused by anthropogenic emissions are occurring at a much faster rate than most of the processes which could potentially compensate for it (it's going to take several hundred years for the ocean to equilibrate, for example, and that's one of the faster ones).

---

Naturally it's increasing faster than anything that could compensate for it, that's why the CO2 concentration has a positive slope.Though there's some science now that does imply a 'lag' in the warming of the oceans.

quote:

---

Given that, straight physics says the temperature has to increase.

---

A little, but more to the point heat has to increase, be it sensible (like you can measure with a thermometer) or latent.As has been said, really "climate change" is a better term than "global warming" for weasal purposes--because it is less specific...and if negative feedback loops conspire to not allow such a great increase in average temperature, climate still has to change to keep that temperature in check .This message has been edited by gene90, 09-15-2005 12:41 PM

quote:

---

Now I really want to move away from Crichton. I can only assume this means you did not read his book. He discusses regional versus global temp issues. Now maybe you did read it and missed it, or somehow read into that section some meaning it didn't have, but I'd rather not get derailed into discussing the book. The only thing I have to say is that if you have not read it, and this came from critics, this is the second patently false statement I have seen about his book from critics.

​

He may very well have made mistakes, but as yet none that anyone has placed in his typewriter.

---

I haven't read it, and should have said so explicitly.

quote:

---

As this is recent data, I am wondering (if you know) whether it has been corroborated by others, and if so if it is from original data or simply using the same generated data.

---

Looking at:Global Warming Trend of Mean Tropospheric Temperature Observed by Satellites by Vinikov and Grody, Science, Vol 302, Issue 5643, 269-272, 10 October 2003.In the abstract they say:

quote:

---

We have analyzed the global tropospheric temperature for 1978 to 2002 with the use of passive microwave sounding data from the NOAA series of polar orbiters and the Earth Observing System Aqua satellite.

---

So they are using the entire dataset accumulated by a number of satellites over many years.There are other groups working on the contradictions between models and even between satellite datasets. For example:Santer et. al., Influence of Satellite Data Uncertainties on the Detection of Externally Forced Climate Change.Abstract:

quote:

---

Two independent analyses of the same satellite-based radiative emissions data yield tropospheric temperature trends that differ by 0.1C per decade over 1979 to 2001. The troposphere warms appreciably in one satellite data set, while the other data set shows little overall change. These satellite data uncertainties are important in studies seekingto identify human effects on climate. A model-predicted "fingerprint" of combined anthropogenic and natural effects is statistically detectable only in the satellite data set with a warmingtroposphere. Our findings show that claimed inconsistencies between model predictions and satellite tropospheric temperature data (and between the latter and surface data) may be an artifact of data uncertainties.

---

I think this segment from the body of the paper should do a fair job of showing the problem:

quote:

---

The MSU record currently comprises measurements from 12 different satellites. Producing homogenous data sets requires accounting for such effects as intersatellite biases, uncertainties in instrument calibration coefficients, changes in instrument body temperature, drift in sampling of the diurnal cycle, roll biases, and decay of orbital altitude (2-6). Until recently, only one group (from the University of Alabama at Huntsville; hereafter, "UAH") had generated temperature records from the raw MSU radiative emissions data (1, 2). On the basis of these records, it has been argued that the troposphere has not warmed over the satellite era, thus casting doubt on the usefulness of climate models (which predict that anthropogenic warming should have occurred), the reliability of thermometer-based observations of surface warming, and the reality of human-induced climate change (7).

​

A second group (Remote Sensing Systems in Santa Rosa, California; "RSS") has now constructed T2 and T4 temperature data sets from the same raw radiative emissions used by UAH (Fig. 1). Over 1979 to 2001, the global mean T2 temperatures estimated by the RSS group warm by roughly 0.1C/decade relative to the corresponding UAH data, which show little net change (6).

---

So the situation is really more complicated than merely saying that satellite data either consistent or inconsistent with a global warming. It looks like the first group to reduce the data found no warming, but others using different instruments found a warming consistent with the models and with the observed surface trend.I'm not a climatologist, statistician, or physicist so I can't claim to really understand everything in that paper. But the parts I do understand seem pretty clear, that reducing data in different ways generates different results. I suspect some circularity in there since they "simulated" MSU temperatures with a model and then compared it data from channels T2 and T4, but you still have the old fashioned thermometers on the surface that, simply put, agree with one dataset and contradict another. I tend to side with the RSS based on this.

quote:

---

Is this increase in increase a significant product of GHGs, or is it more of a synergistic effect between a natural and mandmade source?

---

I don't know the answer offhand, but it seems likely that there are many other effects influencing climate. For example, the little cold spell around 1991--probably causd by the eruption of Mt. Pinatubo. Superimposed on that and the anthropogenic GHG component you have reductions in sulfate emission which could contribute to warming as well as other air pollution controls and you have a run up to around 2000 where Sun becomes more active (I have not checked to see if this cycle caused appreciable changes the radiation budget, but it is my understanding that increased sunspots are associated with slight increases in the solar constant).But I would count on there being other natural factors that for a few decades will enhance or detract from the warming attributed to GHGs. The real strength seems to not be that GHGs are the strongest climate driver, but the most persistant. Volcanic aerosols can cause a cooling but they don't seem to last very long.Actually separating out these factors is probably something that can only be done in the models. The good news is that you can measure temperature and aerosols and GHG concentrations, and testable predictions from the models. I am optimistic that while Earth sciences aren't quite as easy to reduce to the laboratory as chemistry or some of the other, 'harder' fields, it's good science and climate models aren't an exception.

quote:

---

I think there still seem to be pieces missing. I get the correlation (there are rising temps and there are rising CO2 levels), specifically over the last few years, but not the causation... the connection.

---

This is a very important point to make. Correlation is not proof of causality. GHGs may cause climate change but climate change probably affects the atmospheric concentration of GHGs. For example, imagine solar output goes up and warms the climate. That could thaw millions of square kilometers of permafrost and that would create a significant increase in atmospheric CO2. So, yes, that's a piece that may never quite fall into place simply from graphing the two, even though physics does strongly imply that GHGs "should" be absorbing and reradiating outgoing heat back to Earth.

Well you could have fooled me. You certainly seem knowledgeable on this subject in rather important ways. Mmmmm, yeah, I read the RC site's review and it was really unfair and inaccurate. While the science points the site's author wants to make may be valid, and especially to head off misunderstandings others could have, I feel the author was way off target with what Crichton was saying (in specific) as well as meaning to say (in general). I note that some people commented on the review to that effect.My guess would be the author read the book in a defensive mood and so attributed things that were not there, and skipped some bits assuming he understood what must be said. And of course forgot that what wasn't data, were characters in a fictional book.On to reality... Mmmmmhmmmm. This is why I asked the question I did, and this is an interesting answer. I agree that this tends to favor RSS analyses.However I think a point should not be lost in this. I will repeat the section about the data... That is something very similar to what I have had experience with (creating useful homogenous data sets). What it appears has happened is that a first group made a pass at the data to create a set and came up with results that were inconsistent with GW models, and which would have an effect of calling into question the thermometer based observations (on top of GW in general). Then a second group made a pass at the data to create a set and got one that did match the GW model.From where I am sitting, in a skeptic's chair with my skeptic's hat on, I might want to accept for now that that mean's the second team properly "focused" the data, as it does match ground readings, but at the same time not feel very comfortable until a few more independent tries have been done on that data, and even better similar methods for processing of future data, with an equal result.I get a bit nervous having someone say the data set they just massaged out of raw data streams must be better, or should be considered more valid as it matches a preconception we were looking for in the data itself. Yes, and yessssss! Your post with the links was very useful for me, particularly the very first one. In particular I found comparing the Wiki temp graph (from crash), with the giss graph's on forcings, and RC's model runs on temp and radiation. People might want to open each image separately and compare them.The RC site said (iirc) that some of this work was hailed as the smoking gun on GHG effects to climate change. I have to say I have finally found something that looks good. But then again not in the way that should have people saying "told you so".Connecting GHG levels to temps to generate a conclusion were quite problematic, without mechanisms to explain the rather obvious anomolies raised by general GW theory. The emphasis seemed to be on strength of GHGs, and did not address what other mechanisms might be playing into the environment which could create the anomolies as well as the steepness of the rise seen within the 90s.These models seem to answer those in a satisfying, though not perfect, way. And as you suggest it is the persistance, and not the strength of GHGs which seems to be the key here.Looking at the graphs carefully, it appears that GHGs are forcing the general assent of temps (although one could still argue some other factors), with rather strong influences (but more short lived) coming from stratospheric aerosols and solar irradiance.It sort of calls into question the idea that the sharp increase we have just seen is GHG related at all, or will be long lasting with no global reverses, but does suggest that over greater time build up of GHGs will "force" the center of climate dynamics higher.This is a model which appears to have hypothesized interaction of some key mechanisms properly, and I look forward to some future models/tests.One question I do have though, is where they got the aerosol data from before 1900 to create the forcing quotient it would provide. I'm going to dig for it, but if it turns out to be assumptions so as to drive the model runs to generate past data correctly, that will be sort of deflating. I saw a curious argument over this very kind of thing at RC, and the site's author did not provide a satisfying answer to a question posed. One questioner asked about the fact that in some paleo data there was a discordance between a rise in temp and a rise in GHGs (or was it a fall of both) by several thousand years. That seemed highly inconsistent, yet the author passed it off with the above explanation that it is of course reasonable as the climate could have changed the concentration.Okay, but then why not a further climb or fall after that change in concentration? It seems that if more is released, then temps should climb even more, or if it is taken out then temps should fall.If this is not the case and they simply act on each other in different ways at different times, then any discussion of alleviating climate change is made even harder.

---

holmes
"...what a fool believes he sees, no wise man has the power to reason away.."(D. Bros)

Actually what increases is energy. Heat is just one aspect of that increase.Look at the little difference in sea temperature for a large difference in the power of a hurricane, and you can see that straight {temperature\heat} increase is mitigated by transferal into energy systems.

---

we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.

quote:

---

Actually what increases is energy. Heat is just one aspect of that increase.

---

That's technically true, but in meteorology sensible heat is thermal, the term "latent heat" means the energy in a body of air, ie, the heat you could release through condensation. But yeah, you're right about the part that it's an energy increase, and my wording could offend people that know a lot more about thermodynamics.

quote:

---

The energy lost by liquid water during evaporation can be thought of as carried away by, and "locked up" within, the water vapor molecule. The energy is thus in a "stored" or "hidden" condition and is, therefore called called latent heat. It is latent (hidden) in that the temperature of the substance changing from liquid to vapor is still the same. However, the heat energy will reappear as sensible heat (the heat we feel and measure with a thermometer) when the vapor condenses back into liquid water. Therefore condensation (the opposite of evaporation) is a warming process.

---

All emphasis is original.Can't get much more explicit than that. That's from a freshman Introduction to Meteorology textbook, Meteorology Today, Fifth Edition, by C. Donald Ahrens, West Publishing Company, page 33.

quote:

---

Look at the little difference in sea temperature for a large difference in the power of a hurricane, and you can see that straight {temperature\heat} increase is mitigated by transferal into energy systems.

---

Your jargon is different from mine. I should have specified "latent heat" rather than "heat" in that sentence but we're on the same page regarding the actual process.This message has been edited by gene90, 09-15-2005 10:49 PM

Well, you probably have good reason to be cynical.I hope that, at some point, you decide to publish your memoirs, and I hope you stop by to drop us all a line and tell us where we can buy that book.

Well there's no "good" reason to be cynical. The disillusionment was stunning. It appears that I will continue to leak out my life bit by bit at EvC. If I ever reach the point where my memoirs might be valuable, some shrewd person will be able to produce an unauthorized version by tacking all the stuff together from here.But back to the topic at hand. Not sure if you've been keeping up with my back and forth with gene90, but he did present some credible evidence that I would accept as support for one of the more important points, and that is that GHGs are accumulating and an important force in driving the rise in temps. Although I do have some questions about some of the "force" estimates/figures that went into their model. If they have credible sources and are not "reverse calculated" to drive a model, then I'm pretty satisfied, even if more work needs to be done.The data itself was from a recent report which they suggest was considered the "smoking gun" science had been waiting for on the subject. That fact raises a couple of issues. Anyone suggesting they "knew" GW before this study came out seem to have been premature in their opinion. And anyone suggesting that the "proof" here suggests GW is a major crisis (especially that the "dramatic rise" of temps recently is a result of GHGs) appear to be going beyond the data.The data shows that GHGs are staying around and so slowly increasing temps, with the downswings and dramatic upswings being the result of other forces.It does suggest some longterm effects, but not immediate effects unless exacerbated by other forces. It is true that many scientists are cautioning that people should not be ascribing environmental disasters (like Katrina) to GW, and state that there is no current evidence for global escalation. The data would back up such conclusions.Yet such connections/claims appear in many places, including here. If I remember right one of the statements I was refering to of people stating how clear evidence was for GW, how "known" it was, occured within a Katrina thread.Is there a reason to be pointing to weather people are experiencing at this time as signs of climate change? Specifically resulting from GW?Or should people be more cautious and say, okay we do see elevations in GHGs and a connection to a rise in global temp which has the longterm potential to effect climate in ways we are not totally certain but if it does is likely to make storms more powerful as more energy is in the system. We are not necessarily facing this now, but should try and reduce GHGs, as they will continue to persist and have an additive effect.Should people who use storms like katrina be labeled as environmental fundies just as much as people who use such storms to promote their religion?

---

holmes
"...what a fool believes he sees, no wise man has the power to reason away.."(D. Bros)

Given that 3/4ths the planet is water, I would expect most of that re-radiation to be (1) disbursed in the atmosphere (radiated omnidirectionally) and (2) mostly absorbed in the oceans. Given the heat sink that the oceans are, this would require a large influx of heat before much was noticeable (how much would be below the surface?)A couple of new studies show more of a link than ever before between warming and higher energy storms:From Severe Hurricanes Increasing, Study Finds (click) Hurricane's get their energy from the sea temperature, and increase in sea temperature means more energy available for the storms, meaning each storm will be a little bigger. Jargon is no impediment to communication as long as the ideas are conveyed, when jargon gets in the way of communication, then it is counter-productive.

---

we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.

If you stir a pot harder do you get more current or less? All weather is due to temperature differentials, and it doesn't take much to create a wind. The difference between land and air temps is what makes {on-shore\off-shore} breezes in the absence of any larger weather systems.

---

we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.

quote:

---

Given that 3/4ths the planet is water, I would expect most of that re-radiation to be (1) disbursed in the atmosphere (radiated omnidirectionally) and (2) mostly absorbed in the oceans. Given the heat sink that the oceans are, this would require a large influx of heat before much was noticeable (how much would be below the surface?)

---

I don't see a lot of relevance to what I said and the actual point is eluding me but you might be interested in my previous reference in this thread to the warming of the oceans and also a Hansen paper in the June 2005 about a 'lag' in the warming of the system.

quote:

---

Earth's Energy Imbalance: Confirmation and Implications

​

James Hansen,1,2* Larissa Nazarenko,1,2 Reto Ruedy,3 Makiko Sato,1,2 Josh Willis,4 Anthony Del Genio,1,5 Dorothy Koch,1,2 Andrew Lacis,1,5 Ken Lo,3 Surabi Menon,6 Tica Novakov,6 Judith Perlwitz,1,2 Gary Russell,1 Gavin A. Schmidt,1,2 Nicholas Tausnev3

​

Our climate model, driven mainly by increasing human-made greenhouse gases and aerosols, among other forcings, calculates that Earth is now absorbing 0.85 0.15 watts per square meter more energy from the Sun than it is emitting to space. This imbalance is confirmed by precise measurements of increasing ocean heat content over the past 10 years. Implications include (i) the expectation of additional global warming of about 0.6C without further change of atmospheric composition; (ii) the confirmation of the climate system's lag in responding to forcings, implying the need for anticipatory actions to avoid any specified level of climate change; and (iii) the likelihood of acceleration of ice sheet disintegration and sea level rise.

---

This message has been edited by gene90, 09-16-2005 06:37 PM

I was just picking on your use of "ground" rather than surface.thanks for the ref.

quote:

---

I was just picking on your use of "ground" rather than surface.

---

I have no interest in discussing what I said when the meaning is clear.This message has been edited by gene90, 09-16-2005 07:36 PM