In particular, PMOD severely alters the data from the Nimbus7/ERB TSI record during the ACRIM gap from 1989 to 1991. Nimbus7/ERB satellite TSI data during such a short period show a clear upward trend while the PMOD during the same period is almost constant. So the Nimbus7/ERB satellite TSI data has been altered. The alteration of the Nimbus7/ERB data during the ACRIM gap is responsible of the different shape between the ACRIM and PMOD TSI composites. ACRIM composite suggests that TSI underwent a 22-year like cycle: the average TSI value during solar cycle 21-22 (1980-1991) was lower than the average TSI value during solar cycle 22-23 (1991-2002), which seems is larger than the predicted average TSI value during solar cycle 23-24 (2002-2003). PMOD instead shows a very slight negative average trend during the overall three cycles.

Thus, it is evident that with ACRIM the sun would have contributed to the global warming during the last decades. But, what if PMOD is right? Does the adoption of PMOD imply that the sun did not contribute to the warming of the last decades as Lockwood and Frolich claim in their paper? The answer to this question is:

No, it doesn't.

But there is the need of some comment about the mathematical/physical mistakes made by Lockwood and Frolich. I see two of them.

a) The mathematical way they calculate the running means does not have the physical meaning they infer in the test.

In fact, Lockwood and Frolich would like to compare the trend in the solar data with the global temperature trend. To do this they calculate the average during a given period, for example 11-years between 1991 and 2001, and set such a value in the center of such period, that is, in 1996 (their figure 2). Then they move the period to cover the entire available interval from 1978 to 2006. Finally, they compare these moving averages with the temperature trend and deduce their conclusions.

It is evident that this mathematical methodology is physically erroneous. In fact, it assumes that the climate is partially conditioned by the "future" behavior of the sun! Note that by using the above example, the moving average value set in 1996 depends on the TSI values for 5 years in the past and the TSI values for 5 years in the future! And these values are compared with the temperature record.

The problem is that I am not aware of any climate model, or of any physical phenomenon, according to which the present state of a thermodynamic system is a function of the "future" values of the forcings!

“I am not aware of any climate model, or of any physical phenomenon, according to which the present state of a thermodynamic system is a function of the "future" values of the forcings!”

The present state of a thermodynamic system, such as the climate, is evidently a function of the present and past values of the forcings, not of the future ones. Thus, it is evident that Lockwood and Frolich are "anticipating" what eventually might be happening in the future.

b) Thus, what is the right way to do the calculations? The answer is simple, by using a climate model that uses the temporal evolution of the forcings as they are without doing multi-year moving averages that would improperly mix past and future!

The problem is that the actual climate models might be severely incomplete about the sun-climate coupling mechanisms. However, some general properties are well known. In particular, it is well known that because of the thermal inertia of the ocean, the climate response to an increase of the forcing is smoothed and delayed.

Lockwood and Frolich are indeed vaguely aware of this general climate property, (see the first paragraph in their section 3). However, without doing any calculation they conclude that such effect can be neglected!!!

Indeed, the thermal inertia of the climate has a relaxation time response of the order of 10 years; this means that the thermal equilibrium might require approximately 50-100 years. So, Lockwood and Frolich cannot conclude anything by looking at just the last 20 years of solar data. They must look at a larger temporal picture, that is, at what happened at least during the last 50-100 years. And what it is observed during the last century is a net increase of solar activity, and this happens whether we use PMOD or ACRIM since 1978. This net increase of solar activity is indeed lasting since the Little Ice Age of the 17th century. Thus, the sun has surely given a positive contribution to the climate change during the last 50-100 years. 

Indeed, this larger picture effect is evident if we look at the figure 4d in Lockwood and Frolich, even if these authors seem not to realize it. The Be10 record, which is one of the solar records, is monotonically decreasing during the entire 20th century. This means that the solar activity has been likely increasing during the entire century and that, therefore, the sun has contributed to the global warming up to the recent years. Because of the thermal inertia of the ocean the solar induced warming would last even if during the last few years the sun has cooled a little bit as PMOD would suggest.

What can be said is that if the recent predicted cooling of the sun for the solar cycle 23-24 (2002-2013), (which is recovered by both ACRIM and PMOD) will last, it will affect the future climate, not the past one!”

OH YES, ONE MORE THING, THE EARTH STOPPED WARMING

As David Whitehouse noted in a response[1] to the Lockwood/Frolich paper, that the temperatures of the world have leveled off the during last decade after peaking in 1997/98. “Statistically the world's temperature is flat. The world certainly warmed between 1975 and 1998, but in the past 10 years it has not been increasing at the rate it did.”

Indeed, temperatures have declined and then leveled off in the past 8 years. This year despite the predictions by Jones (Hadley Center) as early as January that the year would end up warmest on record, looks to be cooler than 2006, with the record cold Southern Hemisphere winter and a cooling Pacific, and continuing that trend.

***************

Addendum:

The truth is, we can't ignore the sun

By David Whitehouse

Last Updated: 12:01am BST 15/07/2007

According to the headlines last week, the sun is not to blame for recent global warming: mankind and fossil fuels are. So Al Gore is correct when he said, "the scientific data is in. There is no more debate."

Of that the evangelical BBC had no doubt. There was an air of triumphalism in its coverage of the report by the Royal Society.

It was perhaps a reaction to the BBC Trust's recent criticism of the Corporation's bias when reporting climate change: but sadly, it only proved the point made by the Trust.

The BBC was enthusiastically one-sided, sloppy and confused on its website, using concepts such as the sun's power, output and magnetic field incorrectly and interchangeably, as well as not including any criticism of the research.

But there is a deeper and more worrying issue. Last week's research is a simple piece of science and fundamentally flawed. Nobody looked beyond the hype; if they had, they would have reached a different conclusion.

The report argues that while the sun had a significant effect on climate during most of the 20th century, its influence is currently dwarfed by human effects. It says that all known solar influences since about 1990 are downward and because global temperature has increased since then, the sun is not responsible.

No. The research could prove the contrary. Using the global temperature data endorsed by the Inter-national Panel on Climate Change, one can reach a completely different conclusion.

Recently the United States' National Oceanographic and Atmospheric Administration said that 2006 was statistically indistinguishable from previous years.

Looking at annual global temperatures, it is apparent that the last decade shows no warming trend and recent successive annual global temperatures are well within each year's measurement errors. Statistically the world's temperature is flat.

“No scientist could honestly look at global temperatures over the past decade and see a rising curve.”

The world certainly warmed between 1975 and 1998, but in the past 10 years it has not been increasing at the rate it did. No scientist could honestly look at global temperatures over the past decade and see a rising curve.

It is undisputed that the sun of the later part of the 20th century was behaving differently from that of the beginning. Its sunspot cycle is stronger and shorter and, technically speaking, its magnetic field leakage is weaker and its cosmic ray shielding effect stronger.

So we see that when the sun's activity was rising, the world warmed. When it peaked in activity in the late 1980s, within a few years global warming stalled. A coincidence, certainly: a connection, possibly.

My own view on the theory that greenhouse gases are driving climate change is that it is a good working hypothesis - but, because I have studied the sun, I am not completely convinced.

The sun is by far the single most powerful driving force on our climate, and the fact is we do not understand how it affects us as much as some think we do.

So look on the BBC and Al Gore with scepticism. A scientist's first allegiance should not be to computer models or political spin but to the data: that shows the science is not settled.

[Dr David Whitehouse is an astronomer, former BBC science correspondent, and the author of The Sun: A Biography (John Wiley & Sons)]

References:

Boberg, F. H. Lundstedt, H., Hoeksema, J.T., Scherrer, P.H., and Liu, W., Solar mean magnetic field variability: A wavelet approach to Wilcox Solar Observatory and SOHO/Michelson Doppler Imager observations, Journal of Geophysical Research, vol. 107, no. A10, 2002.

Fröhlich, C., and J. Lean, The sun’s total irradiance: Cycles, trends, and related climate change uncertainties since 1976, Geophys. Res. Lett., 25, 4377–4380, 1998.

Lean, J., J. Beer, and R.Bradley, (1995). Reconstruction of solar irradiance since 1610. Implications for climate change. Geophys. Res. Lett., 22, 3195-31982057

Lean, J. (2000), Evolution of the Sun’s spectral irradiance since the Maunder Minimum, Geophys. Res. Lett., 27, 2425– 2428.

Lockwood, M., Frolich, C., Recent oppositely directed trends in solar climate forcings and the global mean surface air temperature, Proc. R. Soc. A doi:10.1098/rspa.2007.1880, Published online

Lockwood, M. Stamper,R., 1999, Long-term drift of the coronal source magnetic flux and the total solar irradiance,  Geophysical Res. Ltrs. GL900485 Vol. 26 , No. 16 , p. 2461

Lockwood, M., Stamper, R. & Wild, M. N. 1999 A doubling of the sun’s coronal magnetic field during the last 100 years. Nature 399, 437–439. (doi:10.1038/20867)

Marsh, N.D. and Svensmark, H.  (2000).  Low cloud properties influenced by cosmic rays. Physical Review Letters 85. 5004-5007.

Marsh, N., and H. Svensmark, (2003) Galactic Cosmic ray and El Niño-Southern Oscillation trends in ISCCP-D2 low-cloud properties, J. Geophys.  Res., 108(D6), AAC 6-1, doi.10.1029/2001JD001264.

Marsh, N., and H. Svensmark, (2003) Solar influence on earth's climate, Space Sci. Rev., 107, 317-325.

Moberg, A., et al. (2005), Highly variable Northern Hemisphere temperatures

reconstructed from low- and high-resolution proxy data, Nature,

433, 613–617.

Scafetta, N., and B. J. West (2005), Estimated solar contribution to the global surface warming using the ACRIM TSI satellite composite, Geophys. Res. Lett., 32, L18713, doi:10.1029/2005GL023849.

Scafetta, N., and B. J. West (2006), Phenomenological solar contribution to the 1900– 2000 global surface warming, Geophys. Res. Lett., 33, L05708, doi:10.1029/2005GL025539.

Scafetta, N. and West, B. J. 2006, Phenomenological solar signature in 400 years of reconstructed Northern Hemisphere temperature record, GRL, received 7 June 2006; revised 25 July 2006; accepted 2 August 2006; published 15 September 2006.

Willson, R (1997). Total solar irradiance trend during solar cycles 21 and 22. Science, 277, 1963-1965

Willson, R (1997) Total solar irradiance trend during solar cycles 21 and 22: Science 277, pp 1963-1965

Willson, Richard C. and Mordvinov, Alexander V., 2003. Secular total solar irradiance trend during solar cycles 21–23. GRL Vol. 30, No 5, 1199,

*****************

Bios:

Joseph S. D'Aleo, CCM, AMS Fellow

Joseph D’Aleo has over 35 years experience in professional meteorology. He was the first Director of Meteorology and co-founder of the cable TV Weather Channel. Mr. D’Aleo was Chief Meteorologist at Weather Services International Corporation and Senior Editor for WSI’s popular Intellicast.com web site. He is a former college professor of Meteorology at Lyndon State College. He is the author of a Resource Guide on El Nino and La Nina. Mr. D’Aleo has frequently written about and made presentations on how research into ENSO and other atmospheric and oceanic phenomena has made skillful seasonal forecasts possible as well as the roles cycles in the sun and oceans have played in climate change. He is currently Executive Director of the International Climate and Environmental Change Assessment Project.

Richard C. Willson, Principal Investigator, ACRIM Experiments

Richard C. Willson holds a doctoral degree in Atmospheric Sciences from the University of California-Los Angeles, and B.S. and M.S. degrees in Physics from the University of Colorado. He is a Senior Research Scientist in the employ of Columbia University’s Center for Climate Systems Research. His work in this field, which began at the University of Colorado and continued at the Jet Propulsion Laboratory and Columbia University, has been in the area of development of state-of-the-art solar irradiance measurement techniques for both total and spectral irradiance. He developed prism, grating, and interference spectroscopy instrumentation for spectral observations in both laboratory and flight environments. He developed the Active Cavity Radiometer instrumentation for total irradiance observations and has conducted flight experiments on balloons, sounding rockets, the Space Shuttle, and satellite platforms. He has served as the Principal Investigator for the Solar Maximum Mission ACRIM I, Space Shuttle Spacelab I and Atmospheric Laboratory for Applications and Science (ATLAS) ACRIM’s, Upper Atmosphere Research Satellite (UARS) ACRIM II and EOS/ACRIM III experiments.

Nicola Scafetta, PhD,  Duke University