I know some of you love to hate GISSTemp. But, fair is fair, El Niño is now showing in the satellites data too. Here’s Channel 5 AMSU:
Below, I subtracted the 20 year mean and show daily channel 5 anomalies:
84 thoughts on “Channel 5 showing warming too.”
Comments are closed.
Lucia,
I would certainly hope that the new el nino shows up in the satellite data. If not, we would have a serious problem. That said, I would not want to be the one to argue that there is an anthropogenic element in the el nino phenomenon, the “A” center piece of the entire AGW/ACC controversy.
tetris– I’m pretty sure El Niños predate the industrial revolution. My point with this post is that this month’s spread in the lower troposphere and the surface may be a very temporary thing. It’s possible the surface actually does warm up 15-30 days before the lower troposphere. So, sometimes, we’ll see these things.
This doesn’t either negate nor confirm anyone’s position about the relative accuracy of satellites and the surface. After all, even if one or the other (or both) have quality issues, the larger weather fluctuations are going to show up.
Indeed, channel 5 is showing a record high temperature for this time of year. And this is at the start of the el nino. Assuming the el nino keeps going, it looks like records are going to be broken all over the place.
Re el nino’s having happened before, of course. But records have not happened before – that’s why they’re records. *Something* must be causing record temperatures. You can’t just say ‘el nino’ a if that is an explanation.
David–
I don’t know if it’s a record high for this time of year. It may well be. However, the Channel 5 lets you draw traces back to August 1998, but I think Channel 5 was operating before that. So… for all I know it was warmer in June 13, 1998 than today.
What I do know is this is the highest Channel 5 since 1999. So, it is high.
Of course we are going to break records if this is a medium to large El Nino. CO2 is causing warming. I wouldn’t be at all surprised if we break on on this go-around.
Lucia,
Spencer’s graph lets you graph the record temperatures – the check box is over on the bottom right. I am assuming that these record temperatures are the ones back to the beginning of the satellite data (1979), but you may be right that it only goes back to mid-1998.
And I probably should have directed my comment better: I was mainly talking to Tetris re the record thing, as I know that you accept luke warming from CO2, but am not sure of his position.
David–
I forgot about that check box. You were probably correct in the first place.
I’m not sure about tetris’s position on warming at all either. I’m pretty sure VG is a “cooler”, but he’s not on this thread.
I’d be surprised if we didn’t break any monthly records during a strong El Nino. I’d have to do some calculations to figure out whether I expect to 2009 to manage to become the hottest year on record. A record breaking El Nino is not necessarily inconsistent with “lukewarming”. Though… some sorts of records would be.
Lucia,
I don’t think that 2009 will be the hottest year on record, although it will perhaps go close. If the el nino continues through to April next year, I expect that the greatest impact will be detected in 2010 (at least, that is what happened with the 1997-98 el nino – extrapolating from that one event is probably a bit silly of me, though …)
On the record highs thing, the check box says ’20-year record highs’. So maybe it only runs back to 1989/1990, rather than back to 1979. However, looking at the UAH satellite data, I doubt that too many record highs were set during the pre 1990 period that have not been broken since.
David–
I think the odds of 2009 being a record is less than 50%-50% for the reasons you state. After all, Jan-Jun is already “in the pocket”. So, the upcoming El Nino would have to be very, very hot to break previous records. But… not impossible.
I agree with you that July 13, Channel 5 is probably a record for July 13, even going back as far as 1950 before the satellites were up there. But… I just forgot about the “record” check box.
David– I fiddled. The temperature in October 2006 exceeds the “20 year record high”. So, maybe that’s the record during the 20 year baseline?
You must be right – there must be a 20-year baseline period, from which the average and record highs and lows are calculated.
Lucia, the UAH and RSS July temperature anomalies will surely increase however the SOI has gone from strongly negative in June to strongly positive in July, see link:
http://www.bom.gov.au/climate/enso/
If the SOI stays positive, it is unlikely that the El Nino will be long-lasting although most climate models predict that it will fall again.
http://www.bom.gov.au/climate/glossary/soi.shtml
In any case, we will know within a matter of a few months whether the El Nino will increase and continue, or fall apart.
By the way, here were my old predictions on GISS average temperature for coming years (from this Feb 2008 thread on climateaudit)
2008: 0.41
2009: 0.55
2010: 0.65
2011: 0.75
2012: 0.80
This was based on a very primitive solar-cycle + warming “model”… 🙂
2008 ended up at 0.44; the first half of 2009 so far is averaging 0.515 – but now I’m thinking I may have underestimated 2009 a bit more than I did even 2008…!
Chuck L,
According to BOM,
“Higher than normal mean sea level pressure (MSLP) at Tahiti during the past fortnight, has caused the recent increase in the SOI. The MSLP at Tahiti is expected to fall again as the Pacific continues to warm and the Trade Winds remain generally weaker than normal. The SOI, therefore, is also expected to fall, that is, become negative again.”
Obviously, they might be wrong. But that is the reason that they are giving for the increase in the SOI.
The satellite used to produce the AMSU-A graph is not compensated for orbital drift.
David, I saw that also, but when comparing historical SOI to La Nina/El Nino, there have rarely been such large disconnects, and when they did occur, the El Nino or La Nina failed to sustain itself. We will know soon enough.
Cheers.
I hope it fails to sustain itself – we (south-east Australia) need better rainfall over the next six months than an el nino promises.
Yes I agree that temps seems to have jumped quite dramatically recently (first 2 weeks July 2009) at 600 mb AMSU (quite the opposite to my silly prediction that the average July would be 0 or negative again). Anyway if you look at all the years since 1998 its not at all spectacular and again if you look at ALL 400mb (where hot spot is supposed to be?), its still below previous years mainly (except for one me thinks). The good thing about this, is this is why you should TRUST UHA data (for warmistas). Now you can say “see its warming because UHA said so” LOL Watch this space…
I think the question that should be asked is where the heat is coming from!!
If there is not extra heat coming in, say, from less cloud cover or lower albedo, this must be ocean cooling!! As there has been more snow cover, close to normal arctic ice, and growing glaciers, now is a good time to be investigating this heat source that can raise temps so quickly!!
Maybe the natural variability has stopped masking that AGW???
Just when you think this Climate Science stuff is REALLY Settled Science, it gets Even More Settled. “How much more settled could this be?”, is my question to you, and the answer is “none”. None more settled. 😉
(Sorry, it’s late)
Andrew
Lucia, if the 1 s.d. curves are correct, it would appear to me that the recent anomolies, while high, wouldn’t be particularly unusual in historical terms. Or am I misinterpreting something.
They might not be unusual, except for the fact that they appear to be records for this time of year – I think the key point is that they are records for the particular *date*, not records overall. (Not yet).
David Gould [16329] and Lucia [16330]
The only thing we all must firmly keep in mind, lest we get lost in our own “intellectual shoe laces”, is that both the el nino and la nina phenomena are independent, not dependent, variables. These massive shifts in regional weather/climate, first so named by the Spanish as they progressively got a measure of the immensity and far reaching effects of so called “pacific” Ocean, were around long before homo sapiens ever figured out how to systemically use hydrocarbon sources of energy.
There is no “A” [as in anthropogenic] in el nino.
Tetris,
Um, of course not. But records are records. It is a given that there have been El Ninos for a very long time. But it is not a given that they will break temperature records.
Duane–
The Channel 5 temperature is not way,way out there, if that’s what you mean.
It’s a little difficult to interpret otherwise because a) the AMSU drifts and b) we only have something like 30 years of operation and the daily variations in weather are fairly noisy. Even if there was no warming, we’d expect to have frequently excursions of daily records outside the record.
I’m not going to try to compute how often we should break the record for “Day N”. The signal is autocorrelated. But basically, if it were a random walk, we have 365 days. How often do you think the temperature will exceed the highest we saw on that specific day in the past 30 years? Answer: Roughly 12 days. Autocorrelation makes things more complicated– but we do expect to see some daily excursions.
My only point with this post is to show people that the troposphere does also seem to show warming. So, we shouldn’t be suggesting the satellites “disagree” with the surface. El Nino progresses; the troposphere is not exactly the surface. It takes some time.
The metrics chosen to represent changes in the thermodynamic state of the Earth’s systems, several kinds of average temperature, do not correctly reflect changes in the energy content of those systems. Instead, because the Earth’s systems are not in equilibrium neither within a subsystem or between subsystems, the metrics measure the changes in the distributions of the energy content of the systems.
This holds also when the changes are measured relative to the average of the metric over some reference period. The systems were not in equilibrium during that period, either, so the change relative to the reference period merely measures the changes in the distributions of the energy content, not a change in the energy content.
The average temperature of thermodynamically heterogeneous systems is set by the energy content of the subsystems that comprise the system. Changes in the energy content of the system can be determined from the average temperature of some of the subsystems only under special circumstances; departures from equilibrium.
Dan
You need to edit “merely measures” to “may only”.
If your point is that it can be dangerous to diagnose the energy content of a large volume from point measurements or even a spatial average , that is so. But the method doesn’t always fail, and we use the method when monitoring processes that are not in equlibrium all the time.
For example:
We might monitor the temperature of the contents of vessel of molten plastic using a temperature probe mounted outside the vessel.
We know that if the the molten plastic warms up, the temperature on the outside surface of the vessel will generally increase. We don’t get too concerned about the fact that there may be temperature gradients inside the plastic, or that the flow pattens may be turbulent resulting in warm blobs transporting heat to the surface at irregular rates. We remain perfectly aware that the heat content of the vessel can’t be directly inferred from the temperature at the surface of the vessel. We know some variations in the temperature at the surface of the vessel may be due to redistribution of heat inside the cauldron arising from warm blobs of plastic rising, cool blobs sinking and generally turbulent or chaotic mixing.
Nevertheless, based on this example, we would be going too if we claimed that we can’t even guess what’s happening to the thermodynamic state of the molten plastic inside the cauldron based on this indirect measurement We would certainly be going too far if we claimed that any and all variations in the temperature at the externally mounted thermocouple were due to redistribution of heat inside the cauldron.
Some of the variations in temperature detected by a single point measurement at the surface of the vessel are due to redistribution of energy inside the vessel; others are not.
The connection to El Nino and setting new temperature records is left as an exercise for the reader. 🙂
Lucia, you can’t discount the possibility that the satellites picked up the heat from passing Jumbo jets on their way to GISSTemp monitoring stations, name airports.
David Gould:
“Tetris,
Um, of course not. But records are records. It is a given that there have been El Ninos for a very long time. But it is not a given that they will break temperature records.”
David, there indeed have been El Nino’s for a long time. There have only been temperature records for a very, very, short time however, and only the 30 year satellite record with anything approaching the consistency and precision for creating a scientific data series.
I don’t. I also don’t discount the possibility that tropospheric temperatures are polluted by Leprechauns flying blimps on their way to soccer matches in the tropics. 🙂
(1) I think it is critically important to locate the region(s) where this sudden warming has appeared at a time when so much of the world has been unusually cool for at least a month because it may lead us to the location of the Pipeline that contains all the missing heat. Perhaps it’s guarded by the leprechauns mentioned above….
(2) As much as admire Dr. Pielke, I can’t help but think he stacked the deck in favor of Dr. Spencer (at the link cited above). Between (a) temperatures returning to their normal averages versus (b) remaining significant high from now on, (b) is a sucker bet even if AGW is a valid theory. Not even the fellows at RealClimate would put money on (b) without odds and/or getting an uncertainty point spread.
Ah ha! I KNEW it was the Leprechauns!
What’s up with the publishing idea? Do you need more money?
Bill– I submitted a comment, but … long story. I have one paper with co-authors getting read to go out. That won’t need money. I need to put together more expansive paper.
lucia (Comment#16380) July 16th, 2009 at 7:43 am
You said: “We remain perfectly aware that the heat content of the vessel can’t be directly inferred from the temperature at the surface of the vessel.”
I attempted to refer to changes in the energy content; not the energy-content level.
I also referred to heterogeneous systems.
I would consider a vessel filled with molten plastic to be a thermodynamically homogeneous system. Additionally I would expect all the material inside the vessel to be at a constant temperature. If sufficient energy is added to the vessel, the liquid plastic will begin top boil and the system will consist of the liquid and vapor phases of the plastic. The possibility that some of the vapor phase becomes superheated cannot be ruled out. By the same token, if energy is extracted from the plastic, some might solidify and some of the solid phase attain a temperature below the boiling temperature. To make the problem more fun, let’s assume that the energy exchange between the system and its surroundings can vary in both space and time, and vast ranges of scales of these.
Let’s consider the case of a vessel filled with liquid water subcooled below the boiling temperature, liquid water at its boiling point, liquid water at its freezing temperature, the solid phase of water subcooled below its freezing temperature, the vapor phase of water superheated above its boiling temperature, the vapor phase of water at its saturation temperature, a mixture of gases which will generally be superheated relative to their boiling temperature, and solid materials having various temperatures and that will never attain a phase-change temperature.
Now, stick a thermometer inside the vessel and tell me the conditions under which we can tell if energy is being added into the system or extracted from the system. Better yet, tell me the arrangement of thermometers that would allow us to know if energy is being added into or extracted from the system.
Why? What’s your definition of thermodynamically homogenous system?
Why? As a general rule, I wouldn’t expect the contents of a tall tank of anything heated from the bottom and cooled from the top and sides to be isothermal. I also don’t expect spaghetti sauce heated from the bottom to be isothermal unless I stir the sauce both vigorously and constantly. The same for cheese sauce, pudding or any number of other fairly viscous fairly low conductivity pseudo-plastics. It’s not even close.
If you are suggesting that heat content is not directly proportional to temperature? Of course it’s not. No one has claimed any such thing.
Is this a vessel? or an entire planet?
Obviously, you aren’t going to easily create a kitchen size pot with all these things happening and persisting for a long time. Scale matter both to whether or not this can happen, and to whether or not one can hope that a rise in temperature at a specific location, averaged over a time period that is large compared to some characteristic time scale describing internal variability of the system, might increase monotonically with heat content. We might not know the constant of proportionality. The time series for temperature might look “noisy”.
But the notion that we at least might be able to infer that long term trend in heat content of the lower atmosphere and/or the ocean based on long term trends in surface temperature of the earth is a plausible one. There may be better places to put thermometers; there may be worse places. But that doesn’t mean we can’t learn anything from examining the surface temperature record.
I think the main thing we learn from the way surface temps are measured is that it is easy to sell a panic.
What was the old saying? “Everyone likes to talk about the weather…” But there was another part to that saying it appears we have forgotten.
Ew, thermodynamics arguments. Why is it that they always turn into a debate over imperfect examples?
Lucia,
The new science paper on direct aerosol effects (http://www.sciencemag.org/cgi/content/full/325/5937/187) might be worth a post. The review on Anthony’s site is a tad over the top (with Hansen’s Scenario A and the old CO2 saturation canard thrown in for good measure), but the findings that direct aerosol effects are in the lower part of the AR4 uncertainty range (0.3 w/m^2 rather than 0.5) could have interesting implications on sensitivity.
That said, the bulk of aerosol effects are indirect, and this paper does not cover those at all. Still, if these finding prove true, it would mean that mean expected anthropogenic forcings are 12.5% higher than the AR4 estimate (1.8 w/m^2 rather than 1.6)
Zeke– The reason the thermodynamics arguments turn into imperfect examples is people want to make overly broad conclusions based on thermodynamics arguments. It’s possible to come up with an example were measuring a surface temperature (or any local temperature) tells us almost nothing about all about heat content. It’s possible to come up with examples where it tells us nearly everything about heat content.
The relationship between surface temperature of the earth clearly falls between these two extremes. (A fact obvious to those who have never taken any thermo but merely watched ice melt in their Mojitos, or watched condense on the outside of the tumbler.) There are no perfect examples for the earth. The earth is the earth.
I’ll read the paper. Thanks.
George Tobin: ‘I think it is critically important to locate the region(s) where this sudden warming has appeared’
NCEP reanalysis shows that the Antarctic has been rather warm the last 30 days. Either 5 to 10 degrees C above normal in patches, or still below -30 degrees depending on which way you want to describe it.
I guess this is something to do with increased circulation of warmer air further north onto the Antarctic Continent, which is a regional change.
There have also been smaller hot spots (around 5 above normal) around North Russia, and NE Canada, and similar strength cool spots (5 below) in central Asia, NW Canada and just north of Antarctica.
With such regional changes occurring, it is probably too hard to pin a global shift of a few 10ths of a degree up onto any particular region in a meaningful way.
http://www.cdc.noaa.gov/map/clim/glbcir_rnl.shtml
Please expalin how a few degrees difference in Antarctica’s deep sub freezing temperatures can possibly mean the Earth is heating in a way could be called catastrophic or dangerous?
Hunter,
It takes a surprisingly large amount of energy to increase temperatures over large areas, and the base from which the temperature increases does not matter (except in certain specific cases involving phase change).
As a point of comparison, if the earth’s temperature dropped 5 or 6 degrees, we would likely see ice sheets over Europe and much of North America.
Obviously, ‘parts of Antarctica’ are not ‘the earth’. But each region is part of the whole. If on balance more regions are warming than cooling, then the earth as a whole is warming.
One question that I would ask is this: what would you consider ‘dangerous’ in terms of climate?
As an example, if Victorian rainfall continues to decline at the rate it has over the last 20 years, that part of Australia is, well, stuffed, to put it bluntly. That is what I would consider ‘dangerous’. The temperature change in that part of the world has been a bit higher than the global average, but not significantly so. Would you consider such a change dangerous?
Think of it this way: so all of a sudden the AGW effect has kicked in (for the last two weeks) = drivel. Remember JUne 2009 = 0.00C. If you actually bothered to tick all the boxes at AMSU (each year) = no significant trend at all. Keep trying warmistas LOL…
David,
Thanks. The problem with using Victoria as an example is that the present weather patterns and climate of Victoria are not really different from the historical norms.
The questions I am asking is two part:
1) Since no one rational is proposing that Antarctica is going to melt, who should cares if the temps on a spot basis in Antarctic are minus 30o or minus 30.5o?
2) When will enough people see through the AGW dependence on confusing weather events or very short term results with *proof* of AGW?
What’s going on with Pielke, Sr.? He’s made some bizarre arguments recently (eg, his claim that sea level rise has stopped since 2006 and anomalies in arctic sea ice have decreased since 2008 (!))
And now he is saying that this latest increase in the satellite record will decide it all? And without even defining terms such as “persist” or giving a time frame?
Boris–
Roger SR. didn’t claim the sea level has permanently stopped rising since 2006 etc. He only said that the observations since those specific times happen to go in that direction.
Those observations were specifically made in context of Rahmstorfs “last few years” statements surrounding “The (Copenhagen) Synthesis Report”.
I suspect he’s saying what I’m thinking: For the past few years, the monitoring services have not been detecting warming. This has lead to a lot of speculation about stalling, changes in climate regimes yada, yada, yada. (These speculations include some published as articles by RC– for example, the Tsonnis and Swanson one.)
The cooling has persisted long enough that people have advanced various theories to explain the ‘pause’. The theories range from Spencer’s related to clouds and feedback, Tsonnis’s & Swanson — and separately Stockwell’s climate regime, to “nothing needs to be explained” to “the earth is cooling, it’s the dawn of an ice age”.
So, now it looks like we are finally going to have an El Nino. Pielke seems to be saying that it looks like the cooling is going to break. But mere breaking isn’t definitive. We will need to watch over the course of the El Nino and after wards to see which of the theories that were attempting to explain “the pause” seem to hold water.
If he means this, I agree with him. I also couldn’t give a specific definition of how long “something” has to “persist” to determine which theory is correct because I don’t know enough information about what statistical properties of “weather noise”. However, I did write a post discussing a few things I’ll be monitoring as El Nino progresses. It’s here: http://rankexploits.com/musings/2009/el-nino-watch-july/
On the other hand, after it happens, it will be possible to apply standard t-test.
The recent warming won’t decide it “all” but, as Roger says, we are in for a test of the AGW hypothesis versus natural variability hypotheses. The recent increase, if indeed due to El Nino, supports the notion that circulation changes influence climate/weather, BUT the real question is, are they more, as, or less important than CO2 forcing?
However, what I find odd is that Roger left out the usual reference to his own favored hypothesis-multiple factor ACC. In point of fact, continued warming would probably support some significant AGW-but what kind of “A”? And of course that says nothing about the magnitude. Which is the most important question IMAO.
Both Pilek’s seem oddly rushed to use this metric as a way to settle the great debate. Perhaps this is an over reading or mis-reading of their statements. The multi-dimensional forcings that Dr. Pielke, Sr. has discussed have been most interesting. Dr. Pilek, Jr.’s discussion of realistic climate and evironmental decision making has been equally fascinating. My hope is that these important voices for rational climate and environmental policies are not going quiet, just when their voices are most needed.
I must still be missing something: I don’t see how an “el nino” event can be construed, any which way, as a sign of “renewed [man-made] warming”. Swanson’s piece at RC argues that the GCMs predict that the current lull in the warming will last until 2020.
tetris,
My take: When a Big Lie finally gets cornered by the truth, people say all kinds of weird stuff.
Andrew
Tetris–
One El Nino, by itself, cannot be construed as “resumption or warming”. However, the distinguishing feature between continued warming is that temperature must continue to warm.
So, if El Nino arrives, is homongonourmous and is followed by a La Nina that is warmer than previous La Ninas, and the next El Nino is warmer than the last one … and so on, everyone has to admit that global warming did not “stop” in 1998.
Remember that the counter argument against global warming stopping, stalling, slowing down, or even just failing to show evidence of accelerating as rapidly as the IPCC projected is that we’ve been sitting in a strong La Nina. If the temperature doesn’t rise much during El Nino, that argument will convince fewer and fewer people.
Just think of an line with a given slope, say 0.15, with sinusoidal variation added to it. ENSO itself has little to do with the resumption of warming. However, the trend in temperatures over the last few ENSO events tends to cancel out ENSO-driven variability, assuming that ENSO events are of a similar magnitude (perhaps homogeneously enormous? homongonormous? :-p ).
Actually it’s surprisingly accurate how the variability can be reproduced just with ENSO and volcanoes. But an increasing trend is needed even for the last decade.
Ahab-that’s true but just because it isn’t volcanoes or ENSO doesn’t mean one can mark it all down to AGW. Come on, think critically!
Andrew_FL
I was talking about variability and ENSO and did not refer to any sort of attribution (being the latter is a completely different issue).
What did you find in what i said that was uncritical thinking? You were probably presuming something i didn’t say 😉
:blush: Sorry Ahab, I’m a bit paranoid.
Andrew_FL
relax mate, we’re not putting money on this 😀
Well, not directly anyway.
Lucia [16460]
I trust you are not suggesting that the close-to decadal levelling-off-followed-by-decreasing global temperatures is the result of a more or less extended la nina effect.
Pielke Sr’s argument about this el nino maybe providing some insight in terms of a “test-of-the-opposing-hypothese” is interesting, but some commentators have suggested, we may already have the basis of for answer.
Fact remains, the wavelengths at which CO2 is supposed to be a determinant forcing variable of warming are exhausted [the impact is on a neg log scale] and as per Swanson’s recent RC piece, given that all GCMs missed the current hiatus, these are useless in terms of their predictive value.
El nino and la nina remain purely independent variables and are part of natural variability and as such, Pielke Sr’s reasoning notwithstanding, tell us very little about man’s effect on global weather patterns or climate.
I don’t think the la nina argument explains how we could have this amount of slowed down warming while the “underying trend” is about +2C/century. But others have suggested it and do believe so.
Given that some believe people disagree, seeing what the actual trend will be after we get past the El Nino represents a test.
I think what’s going to happen is that at the end of the next ENSO cycle, (including a La Nina) we will see the trend will be for some warming, but it will be lower than the multi-model mean of the IPCC models.
tetris (Comment#16494) July 17th, 2009 at 10:52 pm
Oh please. Not that old canard. A quick trip to the Archer MODTRAN site will demonstrate that the wings of the CO2 line are not saturated and that there are still plenty of weak lines beyond the wings that come into play as the concentration increases. Here, I’ll even do it for you (tropical atmosphere 100 km looking down all other settings default):
CO2(ppmv) Iout(W/m2) delta Iout
375 287.812
750 284.610 -3.202
1500 281.375 -3.235
3000 277.984 -3.391
6000 274.342 -3.642
Mr. Payne,
So CO2 is not diminishing in its ability to act as a GHG as its concentration increases?
That is certainly what the link you provided seems to show: Very little change, even with large increases in the CO2 variable.
That would also confirm what the physics of CO2 indicates:
http://motls.blogspot.com/2006/05/climate-sensitivity-and-editorial.html
or this?
http://www.john-daly.com/artifact.htm
Is this a great canard, or is it picking around the edges of something that clearly indicates we are not facing dramatic positive feedbacks or a climate catastrophe?
DeWitt Payne [16497]
Thx for the math. Call it a “canard”[French for duck] but the numbers don’t fly very far. CO2 and the few wavelengths at which it traps radiation are like paint: the first 2 layers make the difference, after that you’re wasting your money.
CO2 ppmv concentrations alone can neither explain nor serve as the main predictor of temperature increases. A different and significant forcing is required without which the entire AGW/ACC story does a lawn dart, and it is becoming pretty obvious that the GCMs have the sign on the most significant forcing wrong, which is why their predictive value is essentially zero [Schmidt and a few others have recently, more or less reluctantly, intimated as much.]
hunter,
I was demonstrating that, contrary to the specific statement about radiative forcing made by tetris, forcing from doubling CO2 continues to be approximately constant (actually it increases with increasing concentration, but not by enough to have a significant effect at current concentrations) over a wide range of concentration higher than present. Forcing being defined as the reduction in emitted radiation from a change in CO2 with everything else held constant. Climate sensitivity, or how much the average temperature changes for a given forcing, is a completely separate issue. Confusing the two does not lead to constructive conversations.
tetris,
CO2 is not at all like paint. Explaining why would take too much space. I suggest consulting a good textbook on atmospheric radiative transfer like A First Course in Atmospheric Radiation by Grant W. Petty
DeWitt,
Thank you. I am not trying to create a non-constructive conversation, much less a destructive one. It seems we do agree on the shrinking return of CO2’s effect.
I appreciate that there is a difference between the impact of CO2 and the sensitivity of climate to CO2, but it seems pretty clear that the two must be rather intimate in their relations, at least from the pov of CO2. If CO2 cannot contribute much to the climate system at higher levels, then why the crisis?
The paint analogy clearly fails, since paint is relatively thin, and if good quality, fixed; while CO2 is spread out and is mobile.
Hunter,
re Victoria, this has been a record low-rainfall period. While records are made to be broken and natural climate variability may well break all records over long enough periods, it seems pretty clear to the BOM that we are looking at something special here.
David Gould,
I tend to believe that anything to do with the idea that we are in an especially dangerous/dramatic/ominous/apocalyptic/tipping point of climate is part of the social movement of AGW, and is not supported by actual evidence.
I think studies like this:
http://www.planetark.com/dailynewsstory.cfm/newsid/39655/story.htm
have not been falsified, simply ignored. In the western US, there is evidence of multi-decade drought cycles. I am pretty confident that Australia, a desert continent, has plenty of evidence that whatever is going on in the less arid areas is not unprecedented.
I think ‘special’, in this case, is in the eyes of the beholders.
hunter,
I guess it depends on the timescales you are looking at. For the direct rainfall records that we have, the current situation in Victoria is unprecedented. I am unsure of what proxy data we have for Victoria, though.
http://www.abs.gov.au/ausstats/abs@.nsf/Latestproducts/1301.0Feature%20Article1012008?opendocument&tabname=Summary&prodno=1301.0&issue=2008&num=&view=
Here is some information on the proxy data for Australia.
The only bit related to Victorian rainfall, though, is this:
“Another record of interest has been derived from crater lakes in south-western Victoria. These lakes are very deep and have catchments of at most a few square kilometres (with the lake surface itself occupying most of the catchment), so the lake level is almost entirely determined by the rainfall-evaporation balance, with runoff and land use change having little or no influence. The lakes studied all show a marked decline in level from about 1840 after having been relatively stable for several centuries. This indicates a marked shift in the rainfall-evaporation balance in the decades around 1840, with a decrease in rainfall being the most likely factor, although changes in evaporation (which could arise from cloudiness, temperature, wind or a combination of these) may also have been involved.”
Hunter,
As a point in your favour, the current rainfall in Victoria does not match the model predictions. If the models are right, then this must be natural variability.
However, one problem with it is that the natural variability theory was used to predict that the drought would “end soon”. This prediction was made at the end of 2006. Two-and-a-half years later, and there is not really any end in sight to the drought at this point.
David,
I think ‘using natural variability theory to predict that the drought would end soon’ is an oxymoron.
One of the comforts of popular theories like AGW is that it offers predictability in an unpredictable system or situation.
Add in the apocalyptic/redemption ethos of AGW, and you have an extremely compelling, although factually incorrect, story. AGW is simple, redemptive, righteous, and wrong.
Since there are good records of decades-long droughts in arid places like Australia and the inter-mountain region of western US, I think long term planners would be wise to adapt to that reality, and not pretend they are going to manage the climate.
Hey Lucia, Sorry I haven’t been posting much. Been up to other things..
http://linux.com/news/embedded-mobile/mids/29263-openmoko-layoffs-lead-to-new-open-hardware-venture
Sounds cool! Let us know when something is on the market. I bet loads of people will want to see it.
Sure it won’t be long. I’ll get some samples back in a couple weeks. Linux is booting now and that will stabilize over time.
DeWitt Payne (Comment#16501) July 18th, 2009 at 11:41 am
*raises hand from the peanut gallery*
There is a big difference between dF/d([CO2]) and F(2*[CO2])/F([CO2]) that you guys ought to be clear about before arguing further on this.
oliver,
Neither of the functions you list is particularly interesting or relevant in this context. dF/d(ln[CO2]) is more like it. I did that curve once for CO2 from 0.1 ppmv to 1000 or 10,000 ppmv, but apparently I didn’t save it. Needless to say, it’s not a straight line. I may still have the data in my notebook. If I find it , I’ll post a link to the graph.
DeWitt Payne (Comment#16535) July 20th, 2009 at 8:06 pm
You’re right, the second expression should have been F(2[CO2])-F([CO2]), which is approximately constant. Then dF/d(ln [CO2]) = a (constant), consistent with the MODTRAN results you posted. That is, each further doubling will does about the same as the previous doubling.
Meanwhile, hunter said this:
“Mr. Payne,
So CO2 is not diminishing in its ability to act as a GHG as its concentration increases?”
In a sense, CO2 is diminishing in its ability, since dF/d([CO2]) is decreasing with [CO2]. This may be a source of misunderstanding about future “forcing levels.”
Oliver,
Yes, I agree about the confusion part. If CO2 were increasing linearly then dF/dt would decrease over time. The problem is that atmospheric CO2 isn’t increasing linearly. I can get a really good fit of the Muana Loa CO2 data with an exponential function with an exponent coefficient that increases linearly with time. Specifically: [CO2(t)]=[CO2(to)]*EXP((0.002625+2.98E-05*t)*t) where t is years since 1959 and [CO2(to)] is 316 ppmv. As long as that continues, the dF/dt will increase with time. That should result in some increase in global heat content. How much, though, is anyone’s guess. I use ‘guess’ advisedly as I don’t trust the model results and I trust the economic scenarios used to drive them not at all. For example, in 17 of the 40 scenarios, world wide petroleum consumption in 2100 will be greater than in 2000. Even most of the optimists in the oil patch don’t believe there’s enough oil in the ground for that to be possible. The pessimists say we’ve already seen peak oil production.
oliver,
So CO2’s GHG effect is/is not negatively logarithmic?
You can build a function which simulates the dTemp/dCO2 which is negatively logarithmic.
It is pretty close to TempC change = -0.0135 ln(CO2) +0.0807
Or right now, the tempC is increasing at 0.030C per ppm(CO2) and this will fall to 0.021C per ppm by the time CO2 reaches the first doubling level of 560 ppm in about 2060.
Climate models are using 0.04C per ppm right now which will fall to 0.0287C by the same 2060.