CLIMATE modelers seem puzzled that small fluctuations in total solar irradiance (TSI) appear to have large influence on the climate. 

They feel it necessary to take recourse to complicated mechanisms. 

For example, Gerald Meehl of the US-National Center for Atmospheric Research (NCAR) and his team have been able to calculate how the extremely small variations in TSI bring about a comparatively significant change in the system “Atmosphere-Ocean”.  [1]

They try to explain how ‘sunspot frequency’ has an unexpectedly strong influence on cloud formation and precipitation. 

One suggested mechanism is a solar-UV enhancement of stratospheric ozone, leading to circulation changes in the troposphere, a possibility explored earlier by British researcher Joanna Haigh.  Another complicated mechanism suggested is increased heating and evaporation from cloud-free regions of the ocean, with the additional moisture transported into the equatorial zone, followed by some kind of positive feedback.

But the answer may really be very simple. 

The tiny (~0.1%) variation of total solar irradiance (TSI) during the solar cycle is only part of the story.  The much stronger variability is that of solar activity (solar wind and magnetic fields), which explains the observed modulation of Galactic Cosmic Radiation (GCR); in turn, the GCR affect cloudiness in the lower troposphere (the ‘Svensmark mechanism’). 

And what makes me so sure about the Galactic Cosmic Ray hypothesis?  It is the observational evidence from isotopic data in stalagmites. [2]

But the GCR explanation is not congenial to AGW alarmists.  The latest (2007) IPCC report ignores the cosmic-ray effects and by focusing only on TSI, disingenuously considers solar influences on climate to be insignificant when compared to the forcing by greenhouse gases.

In this sense then, the paper by Meehl et al does constitute some kind of conceptual breakthrough –even if it is not correct in all its conclusions. 

Professor Reinhard Huettl, Chairman of the Scientific Executive Board of the GFZ agrees: “The study is important for comprehending the natural climatic variability, which – on different time scales – is significantly influenced by the sun. In order to better understand the anthropogenically induced climate change and to make more reliable future climate scenarios, it is very important to understand the underlying natural climatic variability.”

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Notes and Links

1.  Meehl, G.A., J.M. Arblaster, K. Matthes, F. Sassi, and H. van Loon (2009), Amplifying the Pacific climate system response to a small 11 year solar cycle forcing, Science, 325, 1114-1118.
 [Harry van Loon, a pioneer in studies of solar influences on climate.]

2.  NIPCC summary report  “Nature – Not Human Activity – Rules the Climate”   http://www.sepp.org/publications/NIPCC_final.pdf

This is an edited version of SEPP Science Editorial #27-2009 (8/29/09) by Fred Singer.  http://www.sepp.org/

Fred Singer lives in Arlington, Virginia, and holds a B.E.E. in Electrical engineering from Ohio State University and an A.M. and PhD in Physics from Princeton University

Photograph of Fred Singer taken in New York by Jennifer Marohasy in March 2008

But in an AP news story, two of its authors (one is ‘hockey-stick’ inventor Michael Mann from the Real Climate blog) argue that this refutes the skeptics and is “consistent with” greenhouse warming.  Of course, as Roger Pielke, Jr, points out, not long ago we learned from Real Climate that a cooling Antarctica was ‘consistent with’ greenhouse warming and thus the skeptics were wrong: “So a warming Antarctica and a cooling Antarctica are both ‘consistent with’ model projections of global warming. Our foray into the tortured logic of ‘consistent with’ in climate science raises the perennial question, what observations of the climate system would be inconsistent with the model predictions?”

The results are based on very few isolated data from weather stations, plus data from research satellites.  And here is the rub: these are not data from microwave sounding units (MSU), such as are regularly published by Christy and Spencer, but data from infrared sensors that are supposed to measure the temperature of the surface (rather than of the overlaying atmosphere, as weather stations do).

But the IR emission depends not only on temperature of the surface, but also on surface emissivity — and is further modified by absorption of clouds and haze.

These are all difficult points.  Emissivity of snow depends on its porosity and size of snow crystals.  Blowing snow likely has a different emissivity than snow that has been tamped down; so surface winds could have a strong influence.  The emissivity of ice is again different and will depend on whether there is a thin melt layer of water on top of the ice, temporarily produced by solar radiation.  Finally, we have temperature inversions that can trap haze which is essentially undetectable by optical methods from satellites.

The proof of the pudding, of course, is the MSU data, which show a continuous cooling trend, are little affected by surface conditions and are unaffected by haze and clouds.  They are therefore more reliable.

Bottom line:  As it looks to me right now, the Antarctic Continent is cooling not warming.

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1. Eric J. Steig, David P. Schneider, Scott D. Rutherford, Michael E. Mann, Josefino C. Comiso & Drew T. Shindell. Warming of the Antarctic ice-sheet surface since the 1957 International Geophysical Year. Nature 457:459-463, 22 Jan. 2009; doi:10.1038/nature07669

Picture of Dr Singer taken in New York 2008 by Jennifer Marohasy.

This article is from SEPP Science Editorial #4-09 (1/24/09) republished here with permission.  
http://www.sepp.org/

“Most of the observed increase in globally-averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations.” 

How should one interpret this ex cathedra declaration to the faithful?

IPCC helpfully defines ‘very likely’ as ‘90-99% certain’, but they don’t tell us how they reached such well-defined certainty. 

What remarkable unanimity! 

Just how many and whom did they poll?

IPCC doesn’t define the word ‘most.’  We may assume it means anything between 51 and 99%.  Quite a spread. 

But a footnote  informs us that solar forcing is less than 10% of anthropogenic [0.12/ 1.6 W/m2]; so ‘most’ must be closer to 99% than to 51%.

OK; let’s check out the data since 1958.  But we don’t want to rely on contaminated surface data – which IPCC likely used – although they omitted to say so. 

Atmospheric data were readily available to the IPCC in the CCSP-SAP-1.1 report (Fig 3a, p.54; convening lead author John Lanzante, NOAA), with independent analyses by Hadley Centre and NOAA that agree well.  And further, according to GH models, atmospheric trends should be larger than surface temperature trends.

1958 – 2005:  Total warming of +0.5 C  (But how much of that is anthropogenic?)
1958 – 1976:  Cooling
1976 – 1977:  Sudden jump of +0.5 C  (Cannot be due to GHG.)
1977 – 1997:  No detectable trend
1998 – 1999:  El Nino spike
2000 – 2001:  No detectable trend
2001 – 2003:  Sudden jump of +0.3 C  (Cannot be due to GHG.)
2003 – present: No trend, maybe even slight cooling

In conclusion: The IPCC’s ‘most’ is not sustained by observations; the human contribution is very likely only 10% or even less.

By Fred Singer, who lives in Arlington, Virginia, and holds a B.E.E. in Electrical engineering from Ohio State University and an A.M. and PhD in Physics from Princeton University

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*IPCC Synthesis Report, Summary for Policy Makers, November 2007

Photograph of Fred Singer taken in New York by Jennifer Marohasy in March 2008.

This note is from SEPP Science Editorial #17 (December 27, 08), ‘Keeping the IPCC honest’ http://www.sepp.org/