According to an analysis by Scafetta and West published in the March edition of Physics Today (subscription required), the Sun ‘could account for as much as 69% of the increase in Earth’s average temperature.’
Article title: “Is climate sensitive to solar variability?” By Nicola Scafetta of Duke University Physics Department and Bruce J. West of the US Army Research Office, Research Triangle Park, North Carolina
Excerpt: “Thus the average global temperature record presents secular patterns of 22- and 11-year cycles and a short time-scale fluctuation signature (with apparent inverse power-law statistics), both of which appear to be induced by solar dynamics. The same patterns are poorly reproduced by present-day GCMs and are dismissively interpreted as internal variability (noise) of climate. The nonequilibrium thermodynamic models we used suggest that the Sun is influencing climate significantly more than the IPCC report claims. If climate is as sensitive to solar changes as the above phenomenological findings suggest, the current anthropogenic contribution to global warming is significantly overestimated. We estimate that the Sun could account for as much as 69% of the increase in Earth’s average temperature, depending on the TSI reconstruction used. Furthermore, if the Sun does cool off, as some solar forecasts predict will happen over the next few decades, that cooling could stabilize Earth’s climate and avoid the catastrophic consequences predicted in the IPCC report.”
This article is based on Scafetta and West’s previously published peer reviewed papers.
Yes, I know Real Climate are exceedingly rude about this work and RC are entitled to their politically motivated views, just as Scafetta and West are entitled to their’s.
Update: Full article now available here.
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Paul: When they say reconstruction are they talking about PMOD versus ACRIM? Or are they refering to Lean et al (2000) versus the other long term reconstructions?
As a note: Present PMOD values of TSI are lower than the the Maunder Minimum values of the Lean et al reconstruction. Either PMOD is wrong, or they–the powers that be–need to reconsider the Lean et al “TSI Plus Background” Data or another long term reconstruction.
You can view the whole article here:
http://www.fel.duke.edu/~scafetta/pdf/opinion0308.pdf
But TSI has been getting lower since around 1960 (that is the maximum for each solar cycle has been lower), how do they account for that?
“But TSI has been getting lower since around 1960 (that is the maximum for each solar cycle has been lower), how do they account for that?”
Not necessarily. This TSI reconstruction from the University of Colorado shows otherwise. It’s not just maximum sunspot count that matters.
http://lasp.colorado.edu/images/science/solar_infl/Surface-Temp-w-paleo.jpg
In addition, it’s not necessarily just about the Sun when dealing with temperature changes. Despite the denial of the obvious by alarmists, the reality is that once volcanic impacts in the 1980’s and first half of the 1990’s are factored in, there has been little or no warming since the late 1970’s. This corresponds to a major shift in the PDO at that time. Given that we are now due for the PDO to shift back the other way (and it may already be occurring), we may have an opportunity of the next few years to really see what has driven the temperature change over the last 35 years. Yes Luke, I’m kneeling and squeezing my hands as I write this!!
Just for the record, can anyone advise if the IPCC attributes any of the 1990s warming to any other influences but anthropogenic emissions?
Is there any portion that is attributed to landuse change?
I’ll fly a few kites.
Mark – actually hope you are right.
Again we have a very interesting report (peer reviewed paper I’m not sure) that reports a highly technical statistical solar reconstruction. I have no idea whether it stacks up. Is anyone here up to the stats? Full bottle on the Hurst phenomenon perchance?
Despite the usual political posturing by Paul – RC was NOT rude about Scafetta and West – Rasmus presented a highly technical critique. Was science not politics. I guess that’s now rude is it?
But anyway – you don’t have a cooling – you do have a statis – you have had a La Nina. If you want to use a few months a sign it’s all over – well good luck to you. But have a look at previous dips which have risen again.
So maybe you do have some solar and/or PDO influences. Doesn’t mean greenhouse goes away. What happens when the trend changes? And the PDO has not been predictable (except in hindsight). So as usual – it’s not just one thing or another – it’s the cumulative impact of various forcings. And maybe that combination integrates out to a statis (for now!).
Of course a good denialist might chip in that the CO2 sensitivity is low. Well maybe. But also maybe not.
And if you had been paying attention and checked up on me you would have retorted with the latest from Davos (threshold test for blog gimps and you failed guys). So here’s the free kick. (and for Wilkesy – actually I just thought I’d throw this in at random !`~? – Not!)
Geophysical Research Abstracts, Vol. 9, 09766, 2007
SRef-ID: 1607-7962/gra/EGU2007-A-09766
© European Geosciences Union 2007
Solar brightening – a consequence of strong aerosol
decline – and the rapid temperature rise in Europe
R. Philipona (1), C. Ruckstuhl (2), S. Nyeki (3), M. Weller (4), C. Mätzler (3) and L.
Vuilleumier (5)
(1) Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, Davos Dorf, Switzerland, (2) Institute for Atmospheric and Climate Science, Swiss Federal Institute of Technology (ETH), Zürich, Switzerland, (3) University of Berne, Berne, Switzerland, (4) Meteorologisches Observatorium Lindenberg, Deutscher Wetterdienst, Lindenberg, Germany, (5) Station Aerologique, MeteoSwiss, Payerne, Switzerland (rolf.philipona@meteoswiss.ch The rapid temperature increase of 1.2 °C over mainland Europe since the 1980s is considerably larger than expected from anthropogenic greenhouse warming. Solar radiative forcing, recently termed solar brightening, and water vapour feedback, apparently added to the temperature rise. Aerosol optical depth (AOD) measurements at six remote locations from the North Sea up to 3580m a.s.l. in the central Alps show aerosols decreasing by about 60 percent from 1986 to 2000, followed by reduced decline and a present stabilization of AOD. Concurrent, solar radiation measured under cloud-free skies and averaged over 30 Swiss radiation stations below 1000m a.s.l., shows significant increase of 1.3 ±0.7 Wm−2dec−1 between 1981 and 2005, but reduces to 0.6 ±1.0 Wm−2dec−1 from 1995 to 2005. The strong AOD decline and consequent solar brightening most likely steepened the temperature rise at the end of the century, whereas, the observed aerosol stabilization, which ends solar brightening, suggests reduced temperature rise as already observed since the turn of the century.
The anthropogenic change are mainly due to European industry cleanups not Pinatubo whose effect was over by 1994. AOD work only related to Europe but may be more widespread. (Note the article is not implying that the Sun itself really brightened – moreover an aerosol “undimming”).
Science 6 May 2005:
Vol. 308. no. 5723, pp. 847 – 850
From Dimming to Brightening: Decadal Changes in Solar Radiation at Earth’s Surface
Martin Wild,1* Hans Gilgen,1 Andreas Roesch,1 Atsumu Ohmura,1 Charles N. Long,2 Ellsworth G. Dutton,3 Bruce Forgan,4 Ain Kallis,5 Viivi Russak,6 Anatoly Tsvetkov7
Variations in solar radiation incident at Earth’s surface profoundly affect the human and terrestrial environment. A decline in solar radiation at land surfaces has become apparent in many observational records up to 1990, a phenomenon known as global dimming. Newly available surface observations from 1990 to the present, primarily from the Northern Hemisphere, show that the dimming did not persist into the 1990s. Instead, a widespread brightening has been observed since the late 1980s. This reversal is reconcilable with changes in cloudiness and atmospheric transmission and may substantially affect surface climate, the hydrological cycle, glaciers, and ecosystems.
3 more relevant articles in the same issue for those interested. http://www.sciencemag.org/content/vol308/issue5723/index.dtl
Thanks Luke
Ian,
Look at Figure 2 on page 136. Not specific to the 1990’s though.
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_Ch02.pdf
Luke,
There is not much point ignoring you in the future, if I don’t tell you, that I’m going to ignore you.
Otherwise you may just gleefully think, that you driven me off, or maybe, gone the way the parrot did.
So “matey” as far as I’m concerned you do not exist!
Thanks for that link, Mark. As usual it is complete bollocks because so much of the total warming took place prior to 1940, before most of the CO2, CH4, N2O, Halocarbons and Ozone emissions took place.
Now that would make a really interesting graphic. A line graph showing the claimed movements in temperature since 1750 with the estimated times, volumes, and estimate forcings of these claimed forcing agents. In this way the total “unexplained” warming can be identified in both time and extent. And this will provide a closer approximation to the real extent of the negative uncertainty in the GHG forcing calculations.
Notice how all of the positive forcing agents have very small uncertainty levels.
More to the point, did you notice how the portrayal of total uncertainty in the graph does not reconcile with the sum of the uncertain parts? It might be appropriate to provide a net radiative forcing figure that combines the parts above. But it is wrong to do the same net figure for uncertainty because one uncertainty does not cancel out an opposite uncertainty.
The notion of a “net uncertainty” is a complete absurdity. What the graphic should be showing is the total of the negative and positive uncertainties.
So Fig 2 on P136 of AR4WG1 should show
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_Ch02.pdf
Net radiative forcing of +1.6W/m2 with a total negative uncertainty of -2.6W/m2 and a total positive uncertainty of +1.6W/m2. So even by the IPCC’s gonzo maths, the range of climate forcing outcomes is somewhere between -1.0W/m2 and +3.2W/m2.
It is clear that this use of a “net uncertainty” range is intended to convey a level of credibility to the calculations that they simply do not deserve.
More importantly, if the climate muddles have been calibrated to a set of assumptions based on “net uncertainty” then any output from those models will seriously misrepresent the character and scale of the certainty involved.
How sensitive is the climate to solar variation? Answer: Not much (recently).
Not Much Warming Under the Sun
By Phil Berardelli
ScienceNOW Daily News
12 March 2008
Don’t blame the sun for recent global warming. A new analysis, based on historical data rather than computer simulations, shows that our star’s role in climate change has been vastly overtaken by other factors, particularly the human-induced buildup of greenhouse gases.
We get our warmth from the sun, sure, but our climate results from a complex and precarious balance of additional factors, including ocean currents, winds, the amount of snow and ice cover, and even Earth’s orbit and rotational wobble. It’s well-known that our climate has been warming over the past century–a situation most researchers blame on human-induced buildup of carbon dioxide, methane, and other greenhouse gases. Studies have shown that the sun was a driving factor in climate change in preindustrial times, but some researchers have wondered whether changes in the sun’s intensity are continuing to play a major role, possibly by hitting the planet with more heat than normal.
To help nail down the effect of solar radiation, geophysicist Mike Lockwood of the University of Southampton, U.K., examined data available since 1955 on the monthly average output of the sun, including sunspots, magnetic activity, and cosmic-ray variations. Then he compared those data, month by month, with average global temperature records, as well as El Niño- and La Niña-induced weather cycles and the atmospheric effects of major volcanic eruptions. The result, Lockwood and colleagues report in two papers published online this week in the Proceedings of the Royal Society A, is that for the past half-century, the sun has exerted only a small influence on climate–about 3% compared with the warming influence of greenhouse gases and natural climate cycles (see illustration).
Lockwood says a key advantage of his approach is that he relied on hard data rather than computer models. “One problem that crops up [in the climate discussion] is that scientists use complex models that nonspecialists don’t understand and therefore don’t trust,” he explains.
Lockwood’s research represents “a solid look at whether global temperature increases are being driven by changes in the brightness of the sun,” says geophysicist Dáithí Stone of the University of Oxford in the U.K. The work suggests that “there is basically no way that this can be the case,” he says.
http://sciencenow.sciencemag.org/cgi/content/full/2008/312/3
Who would have thought?
I think I’ve got climate change worked out – driven by internal variablity involving known cycles such as the Pacific Decadal Oscillation, the North Atlantic Oscillation, the El Nino/Southern Oscillation, and the North Pacific Oscillation. Chuck in the odd volcano. The external drivers are solar/cosmic factors. I can’t see a significant role for the logarithmic enhanced greenhouse.
Yes Paul. Add some structural warming shifts from irrigated agriculture and vegetation thickening, which are once-off changes rather than part of a trend, and we end up with much ado about nothing.
“Net radiative forcing of +1.6W/m2 with a total negative uncertainty of -2.6W/m2 and a total positive uncertainty of +1.6W/m2. So even by the IPCC’s gonzo maths, the range of climate forcing outcomes is somewhere between -1.0W/m2 and +3.2W/m2.”
I noticed the same thing when I added up all the incremental uncertainties. However, it is possible that some of the uncertainties might be ‘coupled’ which would mean the whole isn’t necessarily the sum of the parts. Regardless, as I’ve said before, “you could drive a Mac truck” through the uncertainty interval which completely contradicts the IPCC edicts of “highly likely” and others who claim the science is settled. What’s even more damning is the claim of certainty on the GHG impacts when they are based on models which make assumptions around the relative impact of other factors including solar and aerosols. Yet the IPCC identifies in its own report that its level of scientific understanding on these factors is very low.
No doubt alarmist climate claims are NOT about the science!
I agree, Mark. But the burden is on them to demonstrate the amount of coupling. This claimed level of certainty for the emissions is even more extraordinary given that the only correlation they have to work with is for temperate Northern Hemisphere. The 50% of the globe between 30N and 30S shows no such certainty, nor does the temperate Southern Hemisphere. So there goes at least 75% of global area. Some certainty.
It also makes clear that they didn’t just pluck their 90% certainty level out of their backsides. They have gone out of their way to manufacture a plausible rationale to justify it.
I just can’t believe they would seriously try on something like a net uncertainty. But their use of the old mercators projection to map temperature change (when GISS’ own software enables them to convert any map to equal area projection) demonstrates the extent they have gone to mislead the public.
This is good work by Mark and Motty. And where are the usual defenders of the climate faith when climate dogma is found to be more than just a little bit fallible? Not a word from them.