Expert: Philip Stahl - 1/1/2012

Question
A few months ago there were some reports in the media that a group at CERN doing cloud chamber experiments on cosmic rays had shown they could play a major role in climate change. I seem to recall that the evidence was so strong that it had even been suggested there was no need any longer to appeal to man-made climate change.

What is your take on these experiments and do you agree with the assessment that cosmic rays can better explain climate change than say a greenhouse effect?

Answer
Hello,

I believe you are referring to the 'CLOUD' experiments conducted by a team at CERN headed by Jasper Kirkby, in which they purportedly "re-created the atmosphere" in their lab, and injected into it cosmic rays created by CERN's own particle accelerators. The experiments tracked the growth of 'seeds' from single molecules into clusters in the presence of UV radiation. Applying an E-field removed any ions present so the rate of seed growth was supposed to be equivalent to that in nature with **no cosmic rays** around. The E-field was then switched off, allowing actual cosmic rays to permeate the chamber for a while. Finally, artificial rays from CERN's accelerators were added to the mix.

On comparing rates of seed formation during the different phases of the experiment, the researchers were able to put a figure on cosmic rays contribution to the process. The results, reported in Nature, suggested naturally occurring rays enhanced molecular seed formation rates by a factor of ten. This implied that the rays' varying intensity could be affecting the climate. Of course, all manner of global warming denier outlets and cranks jumped on this as 'disproving man-made greenhouse warming' predicated on accumulations of CO2. Of course, they extrapolated the results beyond what they actually meant.

For example, Kirkby and his colleagues were nevertheless cautious on the finding, given they also reported that the presence of certain atmospheric pollutants, such as H2So4 (which can incept "acid rain"- which appears when water molecules in the atmosphere react with sulphur dioxide or SO2) might play a counter-seeding role. In that case, seed formation would be repressed by up to 1/1000 of that needed to account for real cloud seeding in nature. Worse, it's already known that clouds are very poorly parameterized in climate models as a whole. This has led to an ongoing debate over the past 8 years on whether in fact the sign of albedo change is positive or negative. (See e.g. ‘Can Earth’s Albedo and Surface Temperature Increase Together’ in EOS, Vol. 87, No. 4, Jan. 24, 2006, p. 37).

What we DO know, and as the authors of the EOS paper first pointed out, is that relatively high albedo (hence net cooling) low clouds have *decreased* during the most recent years, while high clouds "have increased to a larger extent leading to both an increase in cloud amount AND an increased trapping of infrared radiation.” Thus, any experiment dependent exclusively on cloud "seeding" which doesn't take into account their actual altitudes is almost useless!

A far more germane (and longer term) basis for cosmic ray research entails the C14:C12 isotope ratio, such as detected in tree rings, and first noted by the late solar physicist John Eddy. Interestingly, this isotope ratio can also be used as a proxy for solar activity, for example, going back thousands of years to times when there weren't telescopes or where solar spot records are sparse.

In general, C14 is produced in the upper atmosphere via the impact –interaction with high energy cosmic rays, say from galactic sources. Solar activity in turn modulates the intensity of these cosmic rays via the action of the heliosphere which deflects a fraction of the intense cosmic ray flux and other harmful interstellar radiation. At times the Sun is more active, so also will the heliosphere be stronger, shielding the Earth from more intense cosmic rays the effect of which is to reduce the C14 produced in the Earth’s upper atmosphere. Conversely, when the Sun is less active – as it’s been from 2000- 2008 then the heliospheric shield was weaker and more intense cosmic rays penetrated to our upper atmosphere yielding more C14 produced.

It follows from this that if a record could be obtained of the ratio of say C14 to C12 then one would have a proxy indicator of cosmic ray activity as it influences our atmosphere and climate, for any time (With the C14 to C12 ratio extracted from tree rings or other plant tissue). Thus cosmic ray intensity will then be seen to be modulated by the C14:C12 ratio, and the lower this ratio the lower the putative intensity.

Fortuitously, a 2000-year record of C14:C12 deviations has been compiled by P.E. Damon ('The Solar Output and Its Variation', and appears in Eddy's monograph 'The New Solar Physics', The University of Colorado Press, Boulder, 1977, p. 17. To conform with solar activity the plot is such that *increasing radiocarbon (C14)* is downward along the vertical axis and indicated with (+). The deviations in parts per thousand are shown relative to an arbitrary 19th century reference level.

As John Eddy observes concerning this output and the data (ibid.):

“The gradual fall from left to right (increasing C14/C12 ratio) is…probably not a solar effect but the result of the known, slow decrease in the strength of the Earth’s magnetic moment exposing the Earth to ever-increased cosmic ray fluxes and increased radiocarbon production. The sharp upward spike at the modern end of the curve, representing a marked drop in relative radiocarbon, is generally attributed to anthropogenic causes—the mark of increased population and the Industrial Age. The burning of low radiocarbon fossil fuels- coal and oil- and the systematic burning off of the world’s forests for agriculture can be expected to dilute the natural C14/C12 ratio in the troposphere to produce an effect like the one shown.."

In other words, the evidence already inheres in this extended record that by the advent of the Industrial Age the natural C14/C12 ratio in the troposphere had begun to decline, disclosing the greater effects of anthropogenic causes- including the burning of low radiocarbon fossil fuels- coal and oil- and the systematic burning off of the world’s forests - and the mitigation of cosmic ray intensities in relation.

These results comport with modern findings that the last ten years have been the warmest ever, even as CO2 concentrations approach 550 ppm.  This is according to data from the World Meteorological Office. For reference: parts of Greenland had an average temperature 5.4 F above normal in 2010. Meanwhile, Russian officials have ascribed 11,000 “excess deaths” due to heat, arising from their prolonged heat wave in the same year. This year has also been fearsome withmore than 7,500 heat records broken in the U.S. alone. From cosmic rays? Don't think so! By the way, excellent documented footage on the current rapid melting of glaciers world wide can be found at this link:

http://video.pbs.org/video/1108763899


It ought to get even the most blinkered global warming denier's attention!

The job for Kirkby's CERN team (and others seeking to confirm or extend it)? Account for Prof. Gale Christianson's documentation, in his book ‘Greenhouse’ (Penguin, 1999, p. 203)that "never have there been Ice ages when the CO2 concentration was less than 200 ppm."  In effect, the cosmic ray workers need to show the evidence that their cosmic ray influence rivaled or exceeded the effects of CO2. In addition, one would like to see Kirkby's CERN team attempt to quantify C14/C12 ratios into the future using their findings. I.e. in 500 years, or one thousand, what would they expect this ratio to look like, hence quantifying the role of cosmic ray intensity.

In a Sept. 14, 2011 letter to The Wall Street Journal, climate scientist Raymond L. Orbach of the University of Texas, Austin, correctly noted:

"Numerous measurements show that global atmospheric temperatures have been increasing and continue to rise.....There has been no significant change in cosmic ray intensity over the same period in which we have seen the increase in global temperatures.

The issue for climate change is not whether cosmic rays influence clouds, the issue is whether cosmic ray intensities have changed during the years when global atmospheric temperatures have changed. They have not."

Hope this helps clarify these issues!