Finally some recognition of all the anecdotal weather we’ve been talking about here – Anthony
World Meteorological Organization
Thu Aug 21, 2008 1:15am IST
LONDON (Reuters) – The first half of 2008 was the coolest for at least five years, the World Meteorological Organisation (WMO) said on Wednesday.
The whole year will almost certainly be cooler than recent years, although temperatures remain above the historical average.
Global temperatures vary annually according to natural cycles. For example, they are driven by shifting ocean currents, and dips do not undermine the case that man-made greenhouse gas emissions are causing long-term global warming, climate scientists say.
Chillier weather this year is partly because of a global weather pattern called La Nina that follows a periodic warming effect called El Nino.
“We can expect with high probability this year will be cooler than the previous five years,” said Omar Baddour, responsible for climate data and monitoring at the WMO.
“Definitely the La Nina should have had an effect, how much we cannot say.”
“Up to July 2008, this year has been cooler than the previous five years at least. It still looks like it’s warmer than average,” added Baddour.
The global mean temperature to end-July was 0.28 degrees Celsius above the 1961-1990 average, the UK-based MetOffice Hadley Centre for climate change research said on Wednesday. That would make the first half of 2008 the coolest since 2000.
“Of course at the beginning of the year there was La Nina, and that would have had the effect of suppressing temperatures somewhat as well,” Met Office meteorologist John Hammond said.
Life can be strange…just as my mind’s opinion’s are.
That’s the beauty of it.
Life can be anything we choose to have it be….or mean.
You are different than me. Thanks for noticing. Heh.
Hi Steven,
To IPCC’s 300-year projections you wrote, “I don’t think they’re presented as anything more than theoretical projections based on certain assumptions that may not apply.”
Why even put them in the report if they are admittedly meaningless?
You wrote, ” In the meantime, of course, we might get hit by a black swan in the form of an impact event!”
Why limit it to an “impact event”? Lots of other possibilities out there, Steven.
We (“science”, that is) just does not yet have all the answers.
Regards,
Max
Max, I didn’t say that I think an assessment of climate commitment is “meaningless”, simply that the graphs need to be understood for what they’re saying, viz. fig 10.4 -” Values beyond 2100 are for the stabilisation scenarios”.
Indeed, all sorts of black swans could show up. I think it becomes a matter of risk assessment. Personally, I think there is a high risk of long-term accumulative AGW and low risk of climate events that would dwarf it over the period of time that we might sensibly consider (say a century). I guess you disagree, but there we are! 🙂
Hi Steven,
You wrote: “if we simplified the projected warming as being 0.02C per annum, say, we can see far greater natural variability than that on a monthly basis.”
This statement is correct, yet it is, in itself misleading, since it “implies” an underlying projected warming of 0.02C per annum.
Again, you start with the magic word “IF”.
The only extended period of warming that equals 0.02C per annum is the IPCC forecast (or projection) for the early decades of the 21st century.
By averaging the various temperature records over the IPCC “poster period” 1976-1998 (or 1979-2005, however you prefer to look at it) you arrive at a linear warming of somewhere around 0.16C per decade, so around 80% of your figure.
By averaging the various temperature records over the seven and a half years of the 21st century you arrive at a linear cooling of –0.08C per decade, as compared to the IPCC forecast of 0.2C warming per decade.
So let’s update your “IF” sentence to 21st century conditions (different solar activity, different ENSO pattern, but same CO2 emission conditions).
“If we simplified the projected cooling as being 0.008C per annum, say, we can see far greater natural variability than that on a monthly basis.”
The sentence still makes sense and is still just as misleading as your original sentence.
Obviously, seasonal and diurnal swings are far greater than any hypothetical warming or cooling forecast (or projection), as you have said.
But more importantly (and this was my point all along) the unforeseen and non-projected longer-term swings are also greater (viz. 21st vs.late 20th century), which points to the futility of taking one small piece of the puzzle (human CO2 emissions), exaggerating it 3 to 4-fold with assumed positive feedbacks, and using this one piece to develop long range model projections of what is going to happen to world climate over the next century (or, even more absurd, the next three centuries).
Regards,
Max
Hi Steven,
One final point on the IPCC 300-year projections.
You wrote, “Going back to your concern with 300 year projections, and the IPCC figure 10.4, those curves beyond 2100 are assessments of climate commitment (mostly a matter of the thermal inertia of oceans) after stabilising emissions at 2100 levels – so they’re not projections of further changes in inputs beyond that date.”
Sorry, Steven, this is not correct.
If you actually take the time to read the report, you will see that they are various projections of what is projected to happen to global average surface temperature based on different CO2 emission scenarios beyond today.
There are four scenarios presented:
· “consistent composition commitment” (no further increase)
· high greenhouse gas growth
· moderate greenhouse gas growth
· low greenhouse gas growth
The “high growth” shoots off the chart (like Mann’s hockeystick). The “moderate” curve shows a 2300 temperature anomaly of 3.6C, while the “low” curve projects 2.4C.
The “no further increase” curve is essentially flat, gaining less than 0.3C over the 100-year period.
So they are, indeed, projections of further changes in inputs beyond today, contrary to your statement.
Regards,
Max
Hi Steven,
This is beginning to become repetitive. You just wrote, “indeed, all sorts of black swans could show up. I think it becomes a matter of risk assessment.”
Yes, two “black swans” have already shown up recently.
One is a reversal of a 10,000-year record period of high solar activity in the late 20th century and an extremely inactive sun since solar cycle 24 started last January.
Another is the reversal of an unusually active El Nino period over the last 30 years.
These two factors (plus others we have not yet been able to identify) have cancelled out the rapid warming we should have had from record CO2 emissions over this period.
Makes “risk assessment” sort of silly, when we don’t even really know what the real “risk” is.
Are the solar experts who project a cooling planet right? Are the AGW model outputs, which project continued warming right?
Who knows?
I do not. You do not. IPCC does not.
Regards,
Max
RE: John-X (12:27:43) :
We are indeed due for a Bond Event. And, strangely, the world geopolitical scene is not all that different from the 5th Century AD.
manacker says “By averaging the various temperature records over the seven and a half years of the 21st century you arrive at a linear cooling of –0.08C per decade, as compared to the IPCC forecast of 0.2C warming per decade.”
And, what sort of error bars are on that? I am also a little bit skeptical of those numbers. If you look at just the full years (hence ending in 2007), you get values of -0.03 and +0.11 C per decade for HADCRUT3 and NASA GISS records, respectively. However, this is strongly dependent on the exact period of time you look over…e.g., if you extend it back one more year to include year 2000, these trends jump to +0.12 C and +0.25 C per decade, respectively. Adding in year 1999 further increases the trends…although once you put in 1998 they get knocked down somewhat again. And, yes, since the last 7 months have been quite cool, including them will lower these trends somewhat. (I can’t include them easily since I just have the yearly data entered in.)
However, the point is that over short enough periods, before the trends settle down, you are pretty much just doing numerology not real science. At the very least, you have to look over long enough periods that adding or deleting one year (or less than one year!!!) doesn’t drastically alter your conclusions.
Hi Max,
I could have written “let us simplify…”, but never mind –
This statement is correct, yet it is, in itself misleading, since it “implies” an underlying projected warming of 0.02C per annum.
I don’t think it’s in the least misleading – that is (approximately) the IPCC 4th AR projection for the next two decades (not the current one), for all scenarios. How is it misleading to say that’s what’s projected? Perhaps you can clarify?
By averaging the various temperature records over the IPCC “poster period” 1976-1998 (or 1979-2005, however you prefer to look at it) you arrive at a linear warming of somewhere around 0.16C per decade, so around 80% of your figure.
Well, I could dispute that figure, but let’s not quibble. I have referred to projections for the next two decades. The TAR A2 scenario (‘business as usual’) assessed the period 1990-2000as +0.16C, 2000-2010 as a further +0.19C. Basically, projected increases accelerate going forward.
As for your suggesting that 21st century ‘conditions’ are distinguishable from 20th century, on the basis of an <8 year record, I could pick out for you several downward eight-year trends from the 20th century record (I guess you could do that yourself though!). So what’s new?
But more importantly (and this was my point all along) the unforeseen and non-projected longer-term swings are also greater (viz. 21st vs.late 20th century)…
– but ENSO variation is not unforeseen, it’s just that its timing is not predicted (though I think it will be in the future models).It makes no difference whatsoever to long-term trend if it is an oscillation around a natural mean. If it is not, then we would need to look for some way of explaining that!
Regards,
S.
Hi Steven,
When IPCC Chairman, Dr.Pachauri, recently said he would look into what is causing the current temperature plateau, adding “are natural factors compensating?”, he said a big mouthful.
Let’s analyze this train of thought more deeply.
We have been told by IPCC that anthropogenic GHGs (primarily CO2) are a major factor in the global warming our planet has experienced since 1976.
This is being presented as “it must be AGW because our models cannot explain it any other way”.
Not much mention is made of previous periods of warming except the rather short sentence in AR4 WG1 Chapter 3 (p.240): “The picture prior to 1976 has essentially not changed and is therefore not repeated in detail here.”
Pachauri now wonders if “natural factors” may now be causing temperature to cool.
Two “natural factors” that were significantly different in the late 20th century as compared to the most recent years are:
· Solar activity. This reached a 10,000-year high level of activity in the latter 20th century. This has now come to an end and solar cycle 24 has started off with an extremely inactive sun.
· ENSO cycles. These were very strong in the past 30 years, with six major El Nino events since 1973, as compared to only five in the preceding 70 years. This appears to have come to an end, as well, with La Nina events becoming more prevalent.
Now, Pachauri’s dilemma is this.
If he concedes that these natural reversals are causing temperatures to cool today, then he has to concede that they might have had more to do with late-20th century warming than previously assumed.
It is already acknowledged today that the all-time record warm year, 1998, was so warm because of a major El Nino event.
The impact of solar activity is even more tricky for Pachauri. IPCC has limited the 2005 radiative forcing estimate for solar variability to a mere 0.12 W/m^2 (compared to anthropogenic CO2 at 1.66 W/m^2). It has done this by limiting the solar impact to that from direct solar irradiance alone, ignoring any indirect effects.
If we now conclude that an inactive sun is causing cooling today (as we know was the case during the Little Ice Age), we must concede that an active sun may have caused a larger part of the warming experienced in the late 20th century and that, therefore, our estimate of solar radiative forcing is much too low (and that of AGW too high).
A real dilemma.
This may explain why Pachauri has been silent.
He has stated that he hoped the current temperature plateau would not make people think that AGW is “hogwash”.
But he’d better pray for some warming up pretty soon, or people will start believing exactly that and he can fold up his IPCC.
Regards,
Max
All,
Just wanted to say the debate on this thread has been exceptional, civilised and learned and completely puts to shame what passes for debate on sites such as RC and Open Mind
Hi again Max :-),
Ok, I’ll go through your points from my perspective –
We have been told by IPCC that anthropogenic GHGs (primarily CO2) are a major factor in the global warming our planet has experienced since 1976.
Well, I’d say since 1950 at least. They suggest the impact of anthropogenic
influences well before that, but it’s only in the second half of the 20thC that the attribution is confident.
This is being presented as “it must be AGW because our models cannot explain it any other way”
That’s part of the view. The other part is the now very old scientific understanding of the influence of GHGs.
Not much mention is made of previous periods of warming except the rather short sentence in AR4 WG1 Chapter 3 (p.240): “The picture prior to 1976 has essentially not changed and is therefore not repeated in detail here.”
Oh c’mon, Max, there’s stacks on previous warming (and cooling)! I’m not quite sure where to begin… but apart from the entire Palaeo chapter, let’s say you look up solar variability in Ch 2 and you’ll find a whole section on pre-20th century (2.7.1.2)……
Two “natural factors” that were significantly different in the late 20th century as compared to the most recent years are:
· Solar activity. This reached a 10,000-year high level of activity in the latter 20th century.
Perhaps so (there is uncertainty), but the extent of such variability, in terms of forcing influence, and the fact of there being no trend whilst temperatures have increased, needs to be considered.
This has now come to an end and solar cycle 24 has started off with an extremely inactive sun.
Maybe! 😉
· ENSO cycles. These were very strong in the past 30 years, with six major El Nino events since 1973, as compared to only five in the preceding 70 years. This appears to have come to an end, as well, with La Nina events becoming more prevalent.
I think it’s very much too early to conclude that!!! Can you spot such a trend from this? I certainly can’t:
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml
But we shall see, Max, and I’d guess fairly soon – within a couple of years, perhaps (which is soon in climate terms).
Now, Pachauri’s dilemma is this.
If he concedes that these natural reversals are causing temperatures to cool today, then he has to concede that they might have had more to do with late-20th century warming than previously assumed.
No, that doesn’t follow at all. 2005 was, in one record, the hottest year. Your case depends upon 2008, which isn’t even over yet. Let’s guess at what it’s anomaly might be. (I’ll refer to the GISS record for ease of access, though it makes no difference which, tbh). My hunch is it might end up around +0.4C anomaly (I don’t know that, but you don’t know otherwise!). That would mean a ‘reversal’ from recent years. But look back in the record, and you can see equivalent or greater reversals at many points. There’s no more reason on the basis of one year’s evidence to reassess thinking than there was in the ’70s, 80s or 90s, when equivalent cooler years cropped up. I don’t think Pachauri or anyone else is surprised by natural variation! What is worthwhile, I think, is to compare the recent La Nina excursion with previous La Ninas. I think that shows a trend of higher lows.
It is already acknowledged today that the all-time record warm year, 1998, was so warm because of a major El Nino event.
It was acknowledged at the time too, as I established further up the thread!
The impact of solar activity is even more tricky for Pachauri. IPCC has limited the 2005 radiative forcing estimate for solar variability to a mere 0.12 W/m^2 (compared to anthropogenic CO2 at 1.66 W/m^2). It has done this by limiting the solar impact to that from direct solar irradiance alone, ignoring any indirect effects.
Excuse me, but that is simply not true! Feedbacks apply to all forcings, including solar. I have no idea where this notion you’ve presented comes from – can you offer a link? This gets to the root of the problem I have with the ‘solar explanation’. In order to discount CO2 you need to discount feedbacks, but in order to explain temperature change as a result of solar you have to look for feedbacks (or amplification of some kind) of a much greater scale!
If we now conclude that an inactive sun is causing cooling today (as we know was the case during the Little Ice Age), we must concede that an active sun may have caused a larger part of the warming experienced in the late 20th century and that, therefore, our estimate of solar radiative forcing is much too low (and that of AGW too high).
Well, I don’t conclude that! How on earth can our estimate of solar forcing be too low unless you’re about to introduce some new feedbacks? We can measure solar irradiance by satellite now – it’s not as if we’re taking a wild guess.
A real dilemma.
Your dilemma, I’d say, rather than mine or Pachauri’s. There’s no hypothesis for explaining the warming by solar forcing unless you want to pursue the cosmic rays/clouds stuff, or unless you want to posit other feedbacks, in which case you’ll need to explain why they don’t apply to other forcings. And there is no correlation anyway between solar irradiance and temperature in the latter part of the 20th century. You seem to be very doubtful of AGW on the basis of a short-term lack of correlation, yet not doubtful of the solar notion despite a long-term lack of correlation. That puzzles me!
Regards,
Steven
Max,
A further point I meant to make – if you attribute warming to solar, then how do you account for a cooling stratosphere?
🙂
Hi Max,
Just picked up an earlier post of yours (12.26.24)
I wrote:
“Going back to your concern with 300 year projections, and the IPCC figure 10.4, those curves beyond 2100 are assessments of climate commitment (mostly a matter of the thermal inertia of oceans) after stabilising emissions at 2100 levels – so they’re not projections of further changes in inputs beyond that date.”
And you write:
Sorry, Steven, this is not correct.
If you actually take the time to read the report, you will see that they are various projections of what is projected to happen to global average surface temperature based on different CO2 emission scenarios beyond today.
Please note the distinction between my statement “beyond 2100” and yours “beyond today”.
The scenarios run towards stabilisation of GHGs at 2100, presuming various emmissions from today, then beyond 2100 the projection only represents climate commitment.
So, excuse me, but my statement was correct.
(I have read the report!).
🙂
Joel Shore, Ric Werme,
I am not sure linear feedback systems like the one you considered (resulting in a geometric progression) will result in an instability, unless the common ratio “r” is equal to or greater than one – in which case we are saying the result from a cause is equal to or larger than the cause itself. Instabilities should arise from the non-linearity of the system itself, and I think it does not mean an uncontrolled increase, but a sudden shift from one equilibrium state to a completely different equilibrium state due to a very small cause (a stone rolling down from the top of the mountain to the bottom of the valley with a small side-wise push). We need the second derivative to look at instabilities, meaning the system response cannot be linear. The first derivative will only give a condition for equilibrium.
John: I basically agree with everything that you have said above.
And, while I am dishing out agreement, Steve Talbot, I think your 15:42:55 post (and the followup at 16:04:25) is a most excellent one, very well explaining the difficulties faced by those who try to claim that solar forcing can account for a significant amount of the warming that we have seen.
Joel Shore (08:40:51) :
I am not sure why you say that the “current models start at a state that does not reflect current climate conditions”. In fact, while they are certainly not perfect, the current models reproduce the current climate reasonably well, including having the same basic modes of internal variability as are seen in the real climate system.
I may have been overstepping my knowledge a bit, but from what I gather from various posts and http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter8.pdf is that models are initialized with some approximation of real-world conditions, not some known data point:
I would have expected that a key validation step of models would be to take an instance of time, say some point 10 years ago, and let the models crank through that to verify the output matches real life. It may well be that the negative feedbacks in the system produce a stable state (or rising temps, or the actual plateau and fall), but without this sort of validation, I’m at a loss to assess what level of faith I should put in the models.
I moderately disagree with this. Small scale events (thunderstorms, tornadoes, etc) are pretty much invisible on the scale I think the models use. Larger scale things like hurricanes are quite problematic, and some modelers “seed” areas with larval tropical storms big enough to get the models’ attention. Tropical storms move a lot of heat poleward and upward, their loss may be a problem. I’m not as concerned about thunderstorms, perhaps I should be.
Bigger, longer events, including ENSOs really would be nice to model, really big, longterm events like the PDO ought to model well enough to be close to predictive. Those are the sorts of things that have feedback and delays that should lend themselves quite nicely to the scales available to current models. It wouldn’t be hard to convince me they’re more important outputs than are temperature traces.
Those are well beyond the math in weather forecast programs, but it would be nice they’d pop up in GCMs. Heck, when the IPCC talks about warming producing bigger storms, I’d like to see the model output or history that supports that. (BTW, one of my favorite head scratching graphs is at http://www.bluehill.org/annwind.gif and shows a remarkable decline in average wind speed at Blue Hill in Massachusetts from 15 to 13 mph over the last 20 years. It coincides with a decline in strong nor’easters. Mass coastal towns like Scituate used to have storms that flooded local basements frequently, those have tailed way off. I don’t think anyone has a believable explanation.)
Ultimately, the two things that makes me most down on models are 1) The CO2 absorption window is saturated. CO2 was a great GHG in its first 100 ppm, its not so great now and I’m not convinced that the GHG feedback parameter is being determined appropriately. 2) The IPCC public documents discount solar forcing, but history has too many examples of solar activity correlating with temperature, crop yield, etc to dismiss so readily.
Attempts to block research into the Cosmic Ray hypothesis and other non-GHG science is counter productive. The AGW folks who are so certain what the outcome will be should have encouraged enough funding to demonstrate they’re right. Perhaps they are, if so, we could have given that idea a decent burial a few years ago.
I think this is a good read: Luboš Motl
http://motls.blogspot.com/2006/07/carbon-dioxide-and-temperatures-ice.html
Luboš Motl says it all her
http://motls.blogspot.com/2006/07/carbon-dioxide-and-temperatures-ice.html
On Lubos Motl’s blog, I think it is all half truths. The main difference between then (millions of years ago) and now is that we are producing CO2 at an alarming rate. It is interesting that Caillon’s et. al paper is quoted as the proof for the temperature CO2 time lag, without using their explanations. CO2’s lag on temperature was observed in the southern hemisphere. They admit that it is not CO2 that initiated the initial temperature increase (it was due to orbital forcing, etc.), but the CO2 produced from the temperature rise caused further increase in temperature. Now, we are just skipping the first part of waiting for some natural causes to increase CO2, by producing it ourselves.
I have to say that I am rather puzzled by the running battle of words between Steve Talbot and Max (aka manacker). I don’t know what the main perspectives are on each side, so I am quite unable to direct my comments. I will, however, make mine clear as I am not a proponent of AGW being the main source of climate change on this planet over any period of time.
That said, I think it is signifcant that the latest climate models that I know of overestimate the positive feedbacks of various forcings and underestimate the strength of negative feedbacks. I think the testimony of Dr. Roy Spencer points out this aspect, and I would wait first (though others may not) for any research that may show he is incorrect. I will also cite the statement of APS member Roger Cohen (source link below), in which he says:
1. The recorded temperature rise is neither exceptional nor persistent.
2. Predictions of climate models are demonstrably too high, indicating a significant overestimate of the climate sensitivity (the response of the earth to increases in the incident radiation caused by atmospheric greenhouse gases). This is because the models, upon which the IPCC relies for their future projections, err in their calculations of key feedback and driving forces in the climate system.
Me: I think Dr. Spencer’s testimony is key about the this effect on the models and how much it causes them to err.
3. Natural effects have been and continue to be important contributors to variations in the earth’s climate, especially solar variability and decadal and multidecadal ocean cycles.
Me: I would think that a cooling stratosphere should be consisent with an less active sun. While a warming surface would be more consistent with natural processes rather than the alleged effects GHGs.
4. The recorded land-based temperature increase data are significantly exaggerated due to widespread errors in data gathering and inadequately corrected contamination by human activity. [Me: A point I think Anthony has sufficiently demonstrated in his surfacestations.org research]
5. The multitude of environmental and ecological effects blamed on climate change to date is either exaggerated or nonexistent. [Me: here his implication is AGW as to what he means by ‘climate change’]
http://www.climate-skeptic.com/2008/08/practically-a-s.html
And I will also give a quote directly from the Climate Skeptic:
“Only by assuming unbelievably high positive feedback numbers does the IPCC and other climate modelers get catastrophic warming forecasts. Such an assumption is hard to swallow – very few (like, zero) long-term stable natural processes (like climate) are dominated by high positive feedbacks (the IPCC forecasts assume 67-80% feedback factors, leading to forecasts 3x to 5x higher)….
Climate is a long-term quite stable process. It oscillates some, but never runs away. Temperatures in the past have already been many degrees higher and lower than they are today. If a degree or so is all it takes to start the climate snowball running down the infinite hill, then the climate should have already run down this hill in the past, but it never has. That is because long-term stable natural processes are generally dominated by negative, not positive, feedback.”
He goes on to say: “In fact, though most climate models assume positive feedback from the net of water processes (water vapor increase and cloud formation), in fact the IPCC admits we don’t even know the net sign of these factors. And most recent published work on feedback factors have demonstrated that climate does not seem to be dominated by positive feedback factors.”
http://www.climate-skeptic.com/2008/07/absoutely-price.html
I do not quote anything as authoritative on the subject (though Dr Spencer and Dr Cohen may be), but this is representative of my view on the science as I understand it. If the cooling affects of this La Nina are overpowering the warming affect of AGW now, then it is safe to say that in almost all cases nature overpowers whatever influence man has on the change in climate since nature is never static.
Hi Steven,
Coming back to your long rebuttal:
“We have been told by IPCC that anthropogenic GHGs (primarily CO2) are a major factor in the global warming our planet has experienced since 1976.
Well, I’d say since 1950 at least. They suggest the impact of anthropogenic
influences well before that, but it’s only in the second half of the 20thC that the attribution is confident.”
No, Peter. If you read AR4 WG1 closely, you will see that the emphasis is on the “poster period” following 1976.
“This is being presented as “it must be AGW because our models cannot explain it any other way”
That’s part of the view. The other part is the now very old scientific understanding of the influence of GHGs.”
“Very old scientific understanding” sounds nice, Steven, but if you read AR4 you will see multiple references to the “must be AGW because our models cannot explain it any other way” reasoning.
“Not much mention is made of previous periods of warming except the rather short sentence in AR4 WG1 Chapter 3 (p.240): “The picture prior to 1976 has essentially not changed and is therefore not repeated in detail here.”
Oh c’mon, Max, there’s stacks on previous warming (and cooling)! I’m not quite sure where to begin… but apart from the entire Palaeo chapter, let’s say you look up solar variability in Ch 2 and you’ll find a whole section on pre-20th century (2.7.1.2)…… “
Sorry, Steven, I am not talking about “paleo” proxy stuff. I am talking about early 20th century and late 19th century records as actually measured. IPCC does not even mention the late 19th century warming specifically and concedes that the early 20th century warming cannot be explained by the models. It offers rationalizations in the FAQ section for mid-20th century cooling, but these are not very convincing. All of this represents a major weakness in the IPCC justification for AGW as a principal driver of climate.
“Two “natural factors” that were significantly different in the late 20th century as compared to the most recent years are:
· Solar activity. This reached a 10,000-year high level of activity in the latter 20th century.
Perhaps so (there is uncertainty), but the extent of such variability, in terms of forcing influence, and the fact of there being no trend whilst temperatures have increased, needs to be considered.”
Yes, Steven, there is always “uncertainty”, as there is “uncertainty”about AGW as the principal forcing factor for 20th century warming, as there is also no “trend”.
“This has now come to an end and solar cycle 24 has started off with an extremely inactive sun.
Maybe! ;-)”
Are you disputing the fact that solar activity is very low since the advent of solar cycle 24?
“· ENSO cycles. These were very strong in the past 30 years, with six major El Nino events since 1973, as compared to only five in the preceding 70 years. This appears to have come to an end, as well, with La Nina events becoming more prevalent.
I think it’s very much too early to conclude that!!! Can you spot such a trend from this? I certainly can’t.”
It is very clear from the record that there were six major El Nino events in the past 30 years, compared to five in the previous 70 years. Is this a trend? I’d say so. Has it had an impact on temperature? It certainly did in 1997/98.
“But we shall see, Max, and I’d guess fairly soon – within a couple of years, perhaps (which is soon in climate terms).
Now, Pachauri’s dilemma is this.
If he concedes that these natural reversals are causing temperatures to cool today, then he has to concede that they might have had more to do with late-20th century warming than previously assumed.
No, that doesn’t follow at all. 2005 was, in one record, the hottest year. Your case depends upon 2008, which isn’t even over yet. Let’s guess at what it’s anomaly might be. (I’ll refer to the GISS record for ease of access, though it makes no difference which, tbh). My hunch is it might end up around +0.4C anomaly (I don’t know that, but you don’t know otherwise!). That would mean a ‘reversal’ from recent years. But look back in the record, and you can see equivalent or greater reversals at many points. There’s no more reason on the basis of one year’s evidence to reassess thinking than there was in the ’70s, 80s or 90s, when equivalent cooler years cropped up. I don’t think Pachauri or anyone else is surprised by natural variation! What is worthwhile, I think, is to compare the recent La Nina excursion with previous La Ninas. I think that shows a trend of higher lows.”
Your “hunch” is interesting but speculative. The past 8 years have shown no warming in all temperature records and 2008 is definitely colder than previous years. Is this the beginning of a new sharp cooling trend? Who knows? You refer to the GISS record. Based on recent revelations, this record is suspect. The Hadley record may be a bit less suspect, although repeated “forecasts” by Hadley “experts” of “record years” (which do not materialize) make it also a bit suspect. The tropospheric records show more recent cooling (although greenhouse theory tells us that the trposphere should warm more rapidly than the surface). Why is this?
“It is already acknowledged today that the all-time record warm year, 1998, was so warm because of a major El Nino event.
It was acknowledged at the time too, as I established further up the thread!”
And I established further up the thread that it was barely mentioned at the time, but very much ballyhooed several years later when this became politically expedient to distract from a subsequent cooling trend!
“The impact of solar activity is even more tricky for Pachauri. IPCC has limited the 2005 radiative forcing estimate for solar variability to a mere 0.12 W/m^2 (compared to anthropogenic CO2 at 1.66 W/m^2). It has done this by limiting the solar impact to that from direct solar irradiance alone, ignoring any indirect effects.
Excuse me, but that is simply not true! Feedbacks apply to all forcings, including solar. I have no idea where this notion you’ve presented comes from – can you offer a link? “
Yes, Steven, the link is IPSS 2007 SPM. Read it closely and you will see that solar forcing is 0.12 W/m^2 while CO2 forcing is 1.66 W/m^2 (both without “feedbacks”).
Feedbacks are an unsubstantiated fantasy programmed in by computer models. Recent physical observations have demonstrated that the positive feedbacks (water vapor, surface albedo) are essentially cancelled out by negative feedbacks (lapse rate, clouds), leaving the 2xCO2 climate sensitivity at around 0.7-0.8C, as postulated by IPCC without feedbacks.
“This gets to the root of the problem I have with the ’solar explanation’. In order to discount CO2 you need to discount feedbacks, but in order to explain temperature change as a result of solar you have to look for feedbacks (or amplification of some kind) of a much greater scale!”
This is a flawed supposition on your part, Steven. No feedbacks are required to account for all warming experienced to date. 20th century warming was around 0.6-0.7C. Solar impact was around 0.2-0.5C. Spurious effect from UHI effect was around 0.25-0.4C, so there is not much left for CO2. Taking the low end estimates for solar and UHI, we are left with around 0.3C for CO2, which checks out with the “no feedback” estimate of IPCC. Very simple. There is no need to assume a net positive feedback, because it just isn’t there, Steven.
“If we now conclude that an inactive sun is causing cooling today (as we know was the case during the Little Ice Age), we must concede that an active sun may have caused a larger part of the warming experienced in the late 20th century and that, therefore, our estimate of solar radiative forcing is much too low (and that of AGW too high).
Well, I don’t conclude that! How on earth can our estimate of solar forcing be too low unless you’re about to introduce some new feedbacks? We can measure solar irradiance by satellite now – it’s not as if we’re taking a wild guess.”
Sorry, Steven, we can only measure direct solar irradiance (as you say), but we cannot measure the indirect solar impact (for example from cosmic rays), as postulated by Svensmark. Let’s hope that the CLOUD experiment at CERN sheds new light on this area of “low level of scientific understanding” (as assessed by IPCC).
“A real dilemma.
Your dilemma, I’d say, rather than mine or Pachauri’s. There’s no hypothesis for explaining the warming by solar forcing unless you want to pursue the cosmic rays/clouds stuff, or unless you want to posit other feedbacks, in which case you’ll need to explain why they don’t apply to other forcings. And there is no correlation anyway between solar irradiance and temperature in the latter part of the 20th century. You seem to be very doubtful of AGW on the basis of a short-term lack of correlation, yet not doubtful of the solar notion despite a long-term lack of correlation. That puzzles me!”
Steven, the “fatal flaw” in Svensmark’s theory has been postulated by AGW supporters to be that after the 1980s the correlation does not seem to be valid (even though it is valid for many years, and even centuries, prior to 1980). Using the same standard, the AGW theory is also not valid for any period prior to 1976 or subsequent to 1998.
Hope this helps clear up the situation.
Regards,
Max
Bobby Lane has hit the nail on the head when he refers to negative feedbacks from clouds observed by Dr. Roy Spencer and states that he does not believe in “AGW being the main source of climate change on this planet over any period of time”.
IPCC tells us that the warming to be expected from 2xCO2 (without any feedbacks) is around 0.7C, and that the warming from other human GHGs is essentially cancelled out by cooling from human aerosols and land use changes.
Then IPCC tells us that the effect of all assumed feedbacks excluding clouds increases the 2xCO2 warming to 1.9C.
Including an assumed positive feedback from clouds, IPCC tells us that the 2xCO2 warming will be 3.2C. In other words, the assumed positive feedback from clouds increases the 2xCO2 warming from 1.9C to 3.2C.
IPCC does concede that “clouds remain the greatest source of uncertainty” and other studies cited by IPCC state that it is uncertain whether clouds result in a net positive or negative feedback.
Now, as Bobby Lane has pointed out, a recent (post IPCC) study by Roy Spencer has helped clear up some of this “greatest source of uncertainty”. This study, based on physical observations over a five-year period, shows that clouds have a strong negative (i.e. cooling) impact, essentially confirming an earlier hypothesis of Richard Lindzen. In effect, higher sea surface temperatures cause an increase in low altitude clouds (which reflect incoming radiation, thereby causing cooling) and a decrease in high altitude clouds (which absorb outgoing radiation, thereby causing warming).
This net negative feedback is estimated to essentially cancel out any positive feedbacks from water vapor and surface albedo, thereby reducing the 2xCO2 climate sensitivity back to around 0.7C (rather than 3.2C as estimated by IPCC).
In effect, this means that greenhouse warming will cause an increase of 0.7C from 1750 (280 ppm CO2) to 2100 (560 ppm). At 380 ppm today we have already seen around 45% of this warming (0.3C), leaving another 0.4C to be expected from today until the year 2100,
This is certainly not alarming and Bobby Lane is right.
Max
John McLondon (21:13:42)
According to the GHG models, what’s masking CO2 global warming the last several years?
Where are the GHG models dumping all the heat from the amplification of CO2? It’s not going into the oceans.
Why have the oceans shown a slight cooling trend? Where did all that “heat” in the pipe line go? Space?
Old Construction worker,
As I understand it AGW says that temperature will go up with increasing CO2 levels when all other variables are constant. Certainly those other variables are not constant, so it does not mean than we should have a monotonic increase in temperature with CO2 for every year. But on average (5 year, 10 year) when you can somewhat filter out other variables, global temperature will go up.
“Where are the GHG models dumping all the heat from the amplification of CO2? It’s not going into the oceans.”
We are not sure. Note that the sea levels has increased more than it should, consistent with ocean warming, and which cannot be accounted by melting ice alone. May be the heat went way down in the ocean (or may be to space)- see:
http://www.npr.org/templates/story/story.php?storyId=88520025
There may be other mechanisms that we do not yet understand – but CO2 – temperature has been studied for a long time. I think it is rational to base our policies on things we understand, rather than mechanisms that may or may not have any long term effect on the phenomenon.
Max,
When I read Spencer’s paper sometime ago, I came up with the impression that its applicability is highly limited (results from a small region, for a short period of time, etc). Spencer himself made that qualification in his conclusion, I believe. Although his blogs and comments are a lot stronger, but I have great difficulty in believing that part.