This is interesting. This recent paper published in the journal Astronomy & Astrophysics here has done a reconstruction of TSI using Beryllium 10 isotope records combined with sunspot records. The paper suggests that the Total Solar Irradiance (TSI) has increased since the end of the Little Ice Age (around 1850) by up to 6 x more than cited by the IPCC.
Here is how they did it:
For the reconstruction to the past this amplitude is scaled with proxies for solar activity. Two proxies are available for the reconstruction: Group sunspot number, which is available from the present to 1610 AD, and the solar modulation potential extending back to circa 7300 BC. The latter is a measure of the heliospheric shielding from cosmic rays derived from the analysis of cosmogenic isotope abundances in tree rings or ice
cores, and is available with a time resolution of 2-3 solar cycles (Steinhilber et al. 2008). Although sunspot number dropped to zero for a long time during the Maunder minimum, the solar cycle was uninterrupted (Beer et al. 1998; Usoskin et al. 2001) and the modulation potential did not fall to zero. Hence, a reconstruction based solely on sunspot number may underestimate the solar activity during theMaunderminimum. Therefore in our reconstruction we used the solar modulation potential to calculate the long-term variations and sunspot number to superpose them with the 11-year cycle variations (see the Online Section 6.2).
The modulation potential used in the calculations is based on the composite of data determined from the cosmogenic isotope records of 10Be and neutronmonitor. 10Be data are available up to about 1970 (McCracken et al. 2004) and neutron monitor data, which are used to calculate the current solar modulation potential, are available since the 1950s.
A. I. Shapiro, W. Schmutz1, E. Rozanov, M. Schoell, M. Haberreiter1, A. V. Shapiro and S. Nyeki
1 Physikalisch-Meteorologishes Observatorium Davos, World Radiation Center, 7260 Davos Dorf, Switzerland
2 Institute for Atmospheric and Climate science ETH, Zurich, Switzerland
3 Institute for Astronomy ETH, Zurich, Switzerland
Abstract
Context. The variable Sun is the most likely candidate for the natural forcing of past climate changes on time scales of 50 to 1000 years. Evidence for this understanding is that the terrestrial climate correlates positively with the solar activity. During the past 10 000 years, the Sun has experienced the substantial variations in activity and there have been numerous attempts to reconstruct solar irradiance. While there is general agreement on how solar forcing varied during the last several hundred years – all reconstructions are proportional to the solar activity – there is scientific controversy on the magnitude of solar forcing. Aims. We present a reconstruction of the total and spectral solar irradiance covering 130 nm–10 μm from 1610 to the present with an annual resolution and for the Holocene with a 22-year resolution. Methods. We assume that the minimum state of the quiet Sun in time corresponds to the observed quietest area on the present Sun. Then we use available long-term proxies of the solar activity, which are 10Be isotope concentrations in ice cores and 22-year smoothed neutron monitor data, to interpolate between the present quiet Sun and the minimum state of the quiet Sun. This determines the long-term trend in the solar variability, which is then superposed with the 11-year activity cycle calculated from the sunspot number. The time-dependent solar spectral irradiance from about 7000 BC to the present is then derived using a state-of-the-art radiation code.
Conclusions
We present a new technique to reconstruct total and spectral solar irradiance over the Holocene. We obtained a large historical solar forcing between the Maunder minimum and the present, as well as a significant increase in solar irradiance in the first half of the twentieth-century. Our value of the historical solar forcing is remarkably larger than other estimations published in the recent literature.
We note that our conclusions can not be tested on the basis of the last 30 years of solar observations because, according to the proxy data, the Sun was in a maximumplato state in its longterm evolution.All recently published reconstructions agree well during the satellite observational period and diverge only in the past. This implies that observational data do not allow to select and favor one of the proposed reconstructions. Therefore, until new evidence become available we are in a situation that different approaches and hypothesis yield different solar forcing values. Our result allows the climate community to evaluate the full range of present uncertainty in solar forcing.
The full dataset of the solar spectral irradiance back to 7000
BC is available upon request.
Here is the paper, available online in entirety here (PDF) h/t to The Hockey Schtick
“But I still think that the temperatures during ~40s were comparable to the ~80s/90s.”
They were until Steve McIntyre pointed out to Hansen al all that 1934 was the hottest year on record in the US. The Team then sent a huge air-conditioner back through time and cooled of the US temperature records, thus proving the climate models correct and Steve McIntyre wrong.
vukcevic – appears we’ve had a misunderstanding. I agree with your call for cautious interpretation of 10Be – i.e. maybe it just doesn’t represent what many think — but nonetheless it might represent something else — perhaps something even more interesting… Cheers!
–
Stephen Wilde – diplomatic response – well done. I’ll elaborate soon at a preliminary level, but of course the discussion will carry on for months or years. Thanks for your interesting notes. We should be asking around to figure out what existing datasets might represent the variable loopiness you describe. If no such summaries exist, they could be devised. Fractal dimension would be one candidate; perimeter/area ratios another; etc. I have some related ideas to pursue on semi-annual LOD’… Thanks again.
vukcevic, Stephen Wilde, & others,
Please see section 3:
Maraun, D.; & Kurths, J. (2005). Epochs of phase coherence between El Nino-Southern Oscillation and Indian monsoon. Geophysical Research Letters 32, L15709. doi10.1029-2005GL023225.
http://www.cru.uea.ac.uk/~douglas/papers/maraun05a.pdf
(I don’t mean to draw attention to the title, etc. – just section 3, which makes a terribly important point concisely.)
Paul Vaughan says: May 11, 2011 at 9:11 pm
………..
Yes, you got the idea. It will be online by the of the month.
Thanks Paul, you said:
“Maraun, D.; & Kurths, J. (2005). Epochs of phase coherence between El Nino-Southern Oscillation and Indian monsoon. Geophysical Research Letters 32, L15709. doi10.1029-2005GL023225.
http://www.cru.uea.ac.uk/~douglas/papers/maraun05a.pdf
(I don’t mean to draw attention to the title, etc. – just section 3, which makes a terribly important point concisely.)”
The idea seems to be that over time two variable oscillations that are in constant interaction with one another will move towards synchronicity which works against lag effects.
Did I get that right ?
As regards solar and oceanic oscillations I have previously proposed that they are currently more or less on average for most of the time in phase (which in practice means that if the sun puts energy into the system faster for a warming effect via less clouds then the oceans pump it out to space faster for a cooling effect via stronger El Ninos). An antiphase effect as it were.
I have also suggested that over time the phasing could shift so that sun and oceans then supplement each other’s effects rather than offsetting as they do now.
Is there any evidence that the phasing between solar and oceanic oscillations CANNOT change out in the real world as opposed to theoretically as in that paper ?
I see that the finding is limnited to El Nino and the Indian Monsoon. I can envisage them locking together due to their proximity and thus similar responses to a forcing from the global oceans and/or the solar input to the oceans but I can’t see that that suggests that the oscillations of sun and oceans also lock together in similar phases.
Mind you my proposals would still work if the solar and oceanic oscillations WERE locked together but still varied somewhat around the point of balance. They don’t have to go fully in or out of phase to achieve the observed climate variability.
New paper by physicist Denis Rancourt on some of these matters, titled: “Radiation physics constraints on global warming”
http://climateguy.blogspot.com/2011/05/radiation-physics-constraints-on-global_12.html
A few excerpts:
The abstract begins:
“I describe the basic physics of planetary radiation balance and surface temperature, in the simplest and most robust terms possible that capture the essential ingredients of planetary greenhouse warming.” […]
And the abstract ends:
[…] “Earth’s radiative balance determining its surface temperature is shown to be two orders of magnitude more sensitive to solar irradiance and to planetary albedo and emissivity than to the atmospheric greenhouse effect from CO2. All the model predictions robustly follow from the starting assumptions without any need for elaborate global circulation models. A recent critique of the dominant climate change science narrative is evaluated in the light of our model.”
Paper begins:
“Let us start by building the simplest possible model of planetary radiation balance, realistic enough to capture the essential global average features.”
“We take the planet to be a perfect sphere with a smooth and homogeneous surface and to have a thin (compared to the planet radius) and homogeneous atmosphere. The planet is uniformly irradiated by a distant sun.”
[…]
And paper ends:
[…]
The above sensitivity results corroborate these statements in my recent critique [20]:
“There are three main problems with this amplification hypothesis [positive water vapour feedback]. First, there is no empirical support or experimental verification for it. Global average atmospheric water vapour concentration is impossible to measure because water constantly changes phase (vapour, liquid, ice) and is distributed inhomogeneously (vapour, rain, snow, clouds, fog, surface condensation/sublimation/vaporisation, etc.).
Second, there are innumerable hypothetical mechanisms whereby any feedback between CO2 and water vapour could be negative rather than positive and no practical way to evaluate most of these possible mechanisms. For example, just to name one, an increase in CO2 could change the plant ecology in such a way as to reduce evaporation from plants. One could sit and invent hundreds of such plausible scenarios (all equally irrelevant with respect to global climate).
Thirdly, it is likely that there are other negative (or positive?) also negligible climate feedbacks with CO2 that do not depend on coupling with water vapour. CO2 can be a growth limiting plant nutrient such that its impact on albedo might produce greater climate leverage than any greenhouse effect gas coupling could ever achieve?
In summary, as I showed in 2007 [2]: “There is of course much more wrong with state-of-the-art global circulation models (climate models) than the assumption and implementation of CO2-H2O feedback. Although these models are among the most elaborate predictive models of complex non-linear phenomena, they are nonetheless sweeping oversimplifications of the global climate system and its mechanistic intricacies.”
Overall, therefore, there is no established reason to believe that CO2 could be a climate driver and many reasons to conclude that, although CO2 may often follow or correlate with climate indicators [2], climate drivers are related to solar irradiance and albedo and have nothing to do with CO2.”
Stephen Wilde,
My intention was to draw attention to the methodology presented in section 3, which can be applied to any variables (not just AIR & SOI). There’s no “theory”; this is a framework for observing.
There are too many misconceptions about oceanic oscillations in online climate discussions. The inescapable bottom line is that oceans don’t produce their own heat. They just receive insolation.
“Lag” is a maladaptive (but stubbornly persistent) way of framing conceptions about phase relations. “Variable lag” acknowledges more about the nature of the phenomena, but it’s still based on a fundamental misinterpretation of spatially-stationary temporally-global cross-correlation. Complex summaries (as in complex numbers) are needed.
Excessive (& in many cases exclusive) focus on the mean has left many blinded to the variance. Spatially-asymmetric (north-south) temporally-nonstationary (due to solar cycle acceleration) decadal variations of semi-annual amplitude are a source of multidecadal variations.
Interfering very seriously with many researchers’ perceptions are interannual variations. Global waves with local manifestations (“spatiotemporal chaos”) are synchronized with the interannual (not to be confused with decadal) component of solar activity.
More on this in the days & months ahead.
Best Regards.
@Joe Kirklin Lalonde,vukcevic,Stephen Wilde
It seems to me that they used different 10Be data sources to go back to the Maunder minimum, and only Greenland to go back further. From the article,
“Three different datasets of the 10Be data were used: measurements at DYE 3,
Greenland, and the South Pole provided by McCracken et al.
(2004) for the reconstruction back to the Maunder minimum,
and measurements from the Greenland Ice core Project provided
by Vonmoos et al. (2006) for the reconstruction back to 7300
BC.” and “Prior to 1952 the composites are based on
10Be data (cyan based on DYE 3, and red on South Pole records,
bothwith 22-year resolution).”
A TV can insult your intelligence, but nothing rubs it in like a computer