So, what you’re saying is that no global state can be safely regarded as at equilibrium: at any particular time, there may be enhanced forcings that have not fully revealed themselves by equilibration.

Yes, more or less. Of course one needs to be careful to define what one means by “equilibrium”. So for example, if the Earth’s temperature is at equilibrium with external forcings, that doesn’t mean that the temperature won’t fluctuate around the equilibrium temperature as a result of stochastic/cyclic oscillations inherent in the climate system. In that sense the Earth’s surface temperature can be at equilibrium with respect to forcings. We’d have to be clear that we are definig “equilibrium” in that manner (i.e. no temperature trend but fluctuations around a steady temperature…). On the other hand one could insist that equilibrium is defined much more strictly, and then one could assert that the Earth’s temperature is never really truly at equilibrium since it is continuously fluctuating…

I wouldn’t quite say that “there are enhanced forcings that have not fully revealed themselves by equilibration”. The forcings may well be apparent (“have revealed themselves”!), but the “inertias” inherent in the climate system mean that the various elements (troposphere, surface, oceans) haven’t come to equilibrium. That would be the situation with enhanced greenhouse forcing, for example, where the forcing is apparent…however the “strength” of the forcing is uncertain and so far can only be defined within a range of likelihoods on the basis of a load of observational evidence.

foinavon wrote: “………”

No foinavon didn’t write…!

Someone else must have written that Roger…not me!

So, what you’re saying is that no global state can be safely regarded as at equilibrium: at any particular time, there may be enhanced forcings that have not fully revealed themselves by equilibration.

Sure, but it would have enough force to discredit the common criticism that CAGW skepticism amounts to uninformed (and even biased) opinion.

“So this study was a “snapshot” encompassing data covering 5 years. However it seems pretty consistent with what we already know (that atmospheric water vapour concentration rises as the tropospheric temperature rises much as basic atmospheric physics, and models (!) predict)”

This is also consistent with ch4 methane photo disassociation as is observed with increased tropospheric uvb eg UNEP expert assesment 2002,2006,2008
and would be a negative feedback ipcc

Indeed it does,hence zonal climatology eg Cess 1976 . Monin 1984 Raspopov 2008

Thus we can state with some certainty(highly likely) that the datasets eg GISS and hadcru are inhomogeneous ie they are not representative ensembles in the ‘Gibbs’ sense of a global representation historically (before the satellite error) or enhanced observation (as present ) with regard to SST.

This was especially the case in ICOADS Worley et al 2005 when compared to high-quality meteorological data collected in the Northwest Atlantic during the period 1980–92 (russian demilitarized datasets) ie substantive samplig error.

You site papers. I site papers. Who is correct? Both sides in published literature related to oceanic oscillations give decent tries at analysis and come to reasoned conclusions. On the bright side, your cogent posts have improved your standing with me. Have you changed my mind? No. Have you made me think? Yep.

foinavon: I believe the current consensus among researchers in the AGW camp is that the PDO, and by your extention, the AMO, WILL overcome AGW, in the short term (meaning potentially as much as 60 years or more based on your references), possibly reducing us to pre-AGW levels.

Not really Pamela. Have a read of the paper that maksimovich brought to our attention just above, for example. The analyses of ocean currents seems to indicate that the nett effects on global temperature are small. So in the short term we might have a few years where greenhouse-induced warming is countered by some ocean oscillations, and when combined with the sun at its solar minimum, there’s no reason to be surprised at a few years where the temperatures don’t change much or even fall a tad. However, we should be careful not to let these lull us into thinking that global warming might not be as the science indicates. Because remember that those smallish effects that temporarily oppose the warming trend will in a few years likely be supplementing it.

The paper you cite [***] is a good example of the point at issue, namely that the influence of the ocean oscillations (in this case the PDO, given the nomenclature of Pacific Decadal Variability, “PDV”, to cover the entire Pacific), is small, since the effects are out of phase (as they pretty much have to be) in different regions of the oceans.

The authors of your paper show explicitly that:

(a) the nett effects are very small because:

(b) different parts of the oceans are in anti-phase with respect to surface heat distribution.

So Chen et al state, for example:

(p. 2648) “Our PDV mode in both ST datasets has an extremely small global mean amplitude (~0.02K) because of cancellation between regional positive and negative anomalies, and in fact is of opposite sign in GISTEMP and ERSST.V, indicating that its global mean impact is negligible. For comparison, a typical ENSO event has a global mean temperature impact around +/- 0.1K.”

and:

(p. 2636) “As shown in Fig 1, because the PDV signals in high and low latitudes are out of phase and thus offset each other, the global mean temperature change (Fig 1, top) associated with the PDV phenomenon is in the range of +/- 0.02 K, which is negligible compared with the approximately 0.8-K value of GW trend mode and the approximately +/- 0.2-K value of the ENSO phenomenon”

Chen, Y. et al (2008) The spatiotemporal structure of twentieth-century climate variations in observations and reanalysis. Part II: Pacific Pan-Decadal Variability J. Climate 21, 2634-2650

First: “enhanced forcings” has not been proven.

Perhaps…..if we’re taking a philosophical line, where in reality nothing is ever “proven”. But we know that raised greenhouse gas levels constitute an enhanced forcing, and the evidence supports a significant enhanced forcing near 3 oC ish at equilibrium for a doubling of atmospheric CO2.

…..because in the past century the oscillations DID NOT ZERO OUT.

I don’t think the evidence supports that interpretation (not even with capital letters!). That’s not only something that “hasn’t been proven”, but also something for which the evidence indicates specifically is unlikely to be the case (see papers/abstracts in [foinavon (14:21:24)]).

Of course I might be wrong. However a skeptic would like to see some evidence for that assertion (i.e. that ocean currents don’t average out to near zero in their effects on measured surface temperature). And not just a picture of some individual ocean oscillation record, but an analysis that considers the nett effect of ocean oscillations en masse. In my understanding, where this is done, there isn’t very much of a nett ocean current contribution to medium term surface temperature variations (e.g. see abstracts in [foinavon (14:21:24)]).

Third: the factors assumed to be responsible for the cooling in the middle of the last century have NOT been present during the current decade of net cooling temperatures in which no warming has occurred since 1998.

I think you’re confusing the issue by selecting a highly anomalous start year Syl! 1998 was lifted around 0.2 oC above the long term trend by the strongest El Nino of the 20th century. Since global warming is not occurring right now at a rate greater than 0.2 oC per decade, the fact that recent years (2005,2007) were close to 1998 without the benefit of a strong El Nino, indicates that we have warmed quite a bit comparing the decade 2000-now, with 1990-1999. The fact that we haven’t warmed in the past few years is nothing particulalry remarkable. 2008 had a coincidence of “cooling” contributions (La Nina, negative PDO indices, sun right at the bottom of the solar cycle). There will always be periods of temperature statis/cooling on a rising temperature trend where natural variations that can easily combine to give a temporary interannual rise drop of 0.1-0.2 oC provide noise on a temperature trend that may be rising by no more than 0.02 oC per year. We only have to look at the historical record to realize that..

It will take two more decades or so to possibly accomplish a zeroing (if we’re speaking only of the PDO)….

That’s the problem Syl. The PDO is only one ocean current. One can’t base the entire ocean contribution to short/medium term surface temperature by selecting a single ocean oscillation.

The climate models have calculated a climate sensitivity too high and the attribution of factors contributing to warming/cooling is in error.

I don’t think that’s an interpretation that is supported by the evidence. One certainly can’t base such an interpretation on a few years of surface temperature measurements.

The Spatiotemporal Structure of Twentieth-Century Climate Variations in Observations and Reanalyses. Part II: Pacific Pan-Decadal Variability

Chen et al

The spatiotemporal structure of Pacific pan-decadal variability (PDV) is isolated in global long-term surface temperature (ST) datasets and reanalysis atmospheric parameter fields from which El Niño–Southern Oscillation (ENSO) effects have been removed. Empirical orthogonal function (EOF) and combined EOF analysis of the resulting time series identify PDV as one of two primary modes of long-term variability, the other being a global warming (GW) trend, which is addressed in a companion paper (Part I).In this study, it is shown that one of several PDV interdecadal regime shifts occurred during the 1990s.

This significant change in the Pacific basin is comparable but antiphase to the well-known 1976 climate regime shift and is consistent with the observed changes in biosystems and ocean circulation. A comprehensive picture of PDV as manifested in the troposphere and at the surface is described. In general, the PDV spatial patterns in different parameter fields share some similarities with the patterns associated with ENSO, but important differences exist. First, the PDV circulation pattern is shifted westward by about 20° and is less zonally extended than that for ENSO. The westward shift of the PDV wave train produces a different North American teleconnection pattern that is more west–east oriented. The lack of a strong PDV surface temperature (ST) signal in the west equatorial Pacific and the relatively strong ST signal in the subtropical regions are consistent with an atmospheric overturning circulation response that differs from the one associated with ENSO. The analysis also suggests that PDV is a combination of decadal and/or interdecadal oscillations interacting through teleconnections.

Bottom line

“Our results therefore appear to be consistent with the conclusion of Chen et al.
(2002) that the observed top-of-atmosphere tropical radiative flux trend over this time is probably due to natural variability rather than external forcing”

egt Pontryagin and Andronov 1937

“Poincare bifurcation theory was elaborated by the Russian mathematicians Pontryagin and Andronov already in the 20’s and in the 30’s (due to the need to apply these bifurcations to radiophysics). Andronov published (with all the proofs) the theory of the birth of a periodic motion of a dynamical system under the generic loss of stability of an equilibrium position, in the case when two eigenvalues of the linearised system cross the imaginary axis, moving from the stable to the unstable complex half-plane.

Andronov’s theorem claims that (depending on the sign of some higher term of the Taylor series) exactly two generic cases may occur: Either the stability of the equilibrium position is inherited by the new-born limit cycle (whose radius grows like the square root of the difference between the new value of the parameter and the value at the stability loss), or else the radius of the attraction domain, diminishing like the square root of the difference between the growing parameter value and the future value, at which the stability will be destroyed, disappears at the stability loss moment.

The first case is called the mild stability loss, the new-born periodic motion-attractor describes a small oscillation near the old stationary regime. The second case is called the hard stability loss, the behaviour of the system after this stability loss being very far from the equilibrium, loosing its stability. The proofs of these results of Andronov on the phase portraits bifurcations were based on the Pontryagin’s extension of Poincare’s results in the holomorphic case to that of the smooth systems of differential equations.”

http://www.scholarpedia.org/article/Structural_stability

foinavon,

You keep pointing to the Dessler water vapour study when the actual data does not support the global warming case. It was spun that way but the data does not support it.

The relative humidity results are exactly opposite to that predicted by the climate models.

Not sure where you’re getting that interpretation from Bill (and your NASA links don’t work btw).

In Figure 3 of Dessler et al (2008), the absolute humidity (q) rises with increasing temperature as expected. The upper troposphere (low pressure) has a somewhat higher specific humidity and thus a somewhat higher relative humidity (RH) than expected. However averaged over the whole troposphere, the areas of lower and higher RH pretty much average, and so the global average tropsopheric RH stays pretty constant as the temperature varies.

So this study was a “snapshot” encompassing data covering 5 years. However it seems pretty consistent with what we already know (that atmospheric water vapour concentration rises as the tropospheric temperature rises much as basic atmospheric physics, and models (!) predict).The study also indicates that globally averaged, and within the temperature range covered by tropospheric temperature variations between 2003-2008, the tropospheric relative humidity tends to stay fairly constant. That’s also observed in models…

By the way, foinavon. What caused the warming of the first half of the 20′th century?
TSI didn’t vary enough (IPCC still uses outdated figures to do the trick). GHG levels too low. According to you, not enough evidence to attribute it to oceanic or atmospheric oscillations including albedo changes. Taminos vulcanic lull suggestion just makes the current flat temperatures even more inexplicable.

GHG levels weren’t really too low I think. If one inspects, say, the Hadcrut temperature record:

http://www.cru.uea.ac.uk/cru/data/temperature/

The temperature anomaly was around -0.3 in the mid-19th century up towards the end of the 19th century when there was quite a flurry of significant volcanic eruptions that temporarily drove the anomaly towards -0.5 oC. The anomaly reached zero in that odd bump around 1940, and settled around -0.1

It’s pretty likely that there was a bit of recovery from the temperature reduction from the volcanic activity at the end of the 19th century. The CO2 levels were 286 ppm in the mid 19th century and reached around 309 ppm by 1940. Within the mid-value of climate sensitivity (3 oC of warming per doubling of CO2), we expect around 0.35 oC of warming at equilibrium from that rise in CO2.

So we had around 0.3 oC of warming in the early 20th century, nearly all of which could be accounted for by the raised CO2 levels. Of course things aren’t so simple and a full analysis can only be achieved by modeling with the best estimates of the parameterizations and known amplitudes of the various contributions.

This has already been done of course. But if we wanted to make “back of the envelope” estimates we could get the 0.3 oC of early-mid 20th century warming from 0.3 oC of greenhouse forcing (somewhat delayed by the effects of volcanic activity), 0.05 oC of solar warming, and -0.1 oC of aerosolic “cooling” and 0.05 oC of ocean oscillations, if we were determined to include a bit of the latter..something like that seems in accordance with what we know.

The point is that GHG levels weren’t really too low…

Pamela Gray (08:34:43)

The question of entropically-unlikely coordination of ocean currents to give globally persistent warming or cooling of much significance can really only be addressed by analysis rather than supposition.

You cited one paper (a review by Rahmstorf). However Rahmstorf’s review, to the extent that it addressed ocean oscillations, described the major anti-phase oscillations between currents in the N and S hemisphere (these seem likely to be the cause of the Heinrich and D/O events that Rahmstorf describes).

And the anti-phase nature of ocean current oscillations seems to be prevalent where this has been analyzed. In fact the possibility that ocean currents per se might give significant global-scale changes in surface temperature have been addressed in the science.

e.g. recent evidence suggests that the major Pacific (PDO) and Atlantic ocean (AMO) oscillations with long periods are part of the same cycle with long (anti-phase) lead/lag times:

d’Orgeville M and Peltier WR (2007) On the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation: Might they be related? Geophys. Res. Lett. L23705

Abstract: The nature of the Pacific Decadal Oscillation ( PDO) is investigated based upon analyses of sea surface temperature observations over the last century. The PDO is suggested to be comprised of a 20 year quasi-periodic oscillation and a lower frequency component with a characteristic timescale of 60 years. The 20 year quasi-periodic oscillation is clearly identified as a phase locked signal at the eastern boundary of the Pacific basin, which could be interpreted as the signature of an ocean basin mode. We demonstrate that the 60 year component of the PDO is strongly time-lag correlated with the Atlantic Multidecadal Oscillation (AMO). On this timescale the AMO is shown to lead the PDO by approximately 13 years or to lag the PDO by 17 years. This relation suggests that the AMO and the 60 year component of the PDO are signatures of the same oscillation cycle.

and more detailed analysis of the thermodynamics of ocean heat transfer indicates that ocean oscillations per se are unlikely to be significant contributors to large changes in the Earth’s temperature as measured at the surface:

Hoerling M et al. (2008) What is causing the variability in global mean land temperature? Geophys. Res. Lett. 35, L23712

Abstract: Diagnosis of climate models reveals that most of the observed variability of global mean land temperature during 1880-2007 is caused by variations in global sea surface temperatures (SSTs). Further, most of the variability in global SSTs have themselves resulted from external radiative forcing due to greenhouse gas, aerosol, solar and volcanic variations, especially on multidecadal time scales. Our results indicate that natural variations internal to the Earth’s climate system have had a relatively small impact on the low frequency variations in global mean land temperature. It is therefore extremely unlikely that the recent trajectory of terrestrial warming can be overwhelmed (and become colder than normal) as a consequence of natural variability.