Coyote Blog

Today in Forbes, I have an article bringing the layman up to speed on Henrik Svensmark and this theory of cosmic ray cloud seeding.  Since his theory helped explain some 20th century warming via natural effects rather than anthropogenic ones, he and fellow researchers have face an uphill climb even getting funding to test his hypothesis.  But today, CERN in Geneva has released study results confirming most of Svensmark's hypothesis, though crucially, it is impossible to infer from this work how much of 20th century temperature changes can be traced to the effect (this is the same problem global warming alarmists face -- CO2 greenhouse warming can be demonstrated in a lab, but its hard to figure out its actual effect in a complex climate system).

From the article:

Much of the debate revolves around the  role of the sun, and though holding opposing positions, both skeptics and alarmists have had good points in the debate.  Skeptics have argued that it is absurd to downplay the role of the sun, as it is the energy source driving the entire climate system.  Michael Mann notwithstanding, there is good evidence that unusually cold periods have been recorded in times of reduced solar activity, and that the warming of the second half of the 20th century has coincided with a series of unusually strong solar cycles.

Global warming advocates have responded, in turn, that while the sun has indeed been more active in the last half of the century, the actual percentage change in solar irradiance is tiny, and hardly seems large enough to explain measured increases in temperatures and ocean heat content.

And thus the debate stood, until a Danish scientist named Henrik Svensmark suggested something outrageous -- that cosmic rays might seed cloud formation.  The implications, if true, had potentially enormous implications for the debate about natural causes of warming.

When the sun is very active, it can be thought of as pushing away cosmic rays from the Earth, reducing their incidence.  When the sun is less active, we see more cosmic rays.  This is fairly well understood.  But if Svensmark was correct, it would mean that periods of high solar output should coincide with reduced cloud formation (due to reduced cosmic race incidence), which in turn would have a warming effect on the Earth, since less sunlight would be reflected back into space before hitting the Earth.

Here was a theory, then, that would increase the theoretical impact on climate of an active sun, and better explain why solar irradiance changes might be underestimating the effect of solar output changes on climate and temperatures.

I go on to discuss the recent CERN CLOUD study and what it has apparently found.

There may be something interesting coming out in the climate front over the next few weeks from CERN.

Years ago, a researcher named Henrik Svensmark developed a hypothesis that cosmic rays can seed cloud formation, and thus when there are more cosmic rays, there may be more clouds.  This is interesting because it may act as a sort of solar amplification.

Changes in the sun's output through varying solar cycles are measurable, but seem to some scientists to be too small to drive substantial temperature changes on Earth.  But a more active sun tends to blow cosmic rays away from the Earth, thus reducing their incidence.  Therefore, if a more active sun reduced cooling clouds, and a less active sun increased cooling clouds, this might explain a larger effect for the sun.

I have avoided discussing Svensmark much, since the evidence seemed thin, though several labs recently have confirmed his hypothesis, at least in the laboratory.  But Svensmark is definitely a topic among some climate skeptics.  The reason is that higher solar activity levels  in the second half of the twentieth century coincided with much of the 20th century warming that is blamed on manmade CO2.  Svensmark's theory, if true, might force scientists to apportion more of the historic warming to natural causes, thus reducing the estimated sensitivity of the climate to man-made CO2.

But apparently the CERN lab has been undertaking a substantial study to confirm or deny Svensmark's hypothesis.  The results have not been released, but skeptics are beginning to anticipate that CERN's work has confirmed the hypothesis of cosmic ray cloud seeding.  Why?  Because of the dog that did not bark, or rather was told not to bark.

Via Watts Up With That:

CERN Director General Rolf-Dieter Heuer told Welt Online that the scientists should refrain from drawing conclusions from the latest experiment.

“I have asked the colleagues to present the results clearly, but not to interpret them,” reports veteran science editor Nigel Calder on his blog. Why?

Because, Heuer says, “That would go immediately into the highly political arena of the climate change debate. One has to make clear that cosmic radiation is only one of many parameters.”

Skeptics are suggesting that had CERN disproved Svensmark, and thus protected the hypothesis that CO2 is driving most current warming, they would not have hesitated to draw exactly this conclusion in public.  Only a finding considered more consistent with the skeptical position would cause them to go silent, trying to avoid the taint from the politically correct intelligentsia that would come from even partially confirming a skeptic talking point.

I have to agree that Heuer's comments seem to telegraph the result.  I have read a ton of global warming related studies.  And every single one I have read that has ever published negative results vis a vis the hypothesis of catastrophic manmade global warming has felt obligated to put in a sentence at the end that says something like "but of course this does not in any way disprove the hypothesis of anthropogenic global warming and we fully support that hypothesis despite these results."  The absolute fear of becoming an outcast for coming up with the "wrong" result is palpable in reading these papers, sort of like the very careful language a report in Soviet Russia might have used to even mildly criticize some aspect of the state.  Of course, no such disclaimer can be found with narrow positive results - these are always immediately extrapolated  (in fact over-extrapolated in press releases) to be the final nail in the coffin proving once and for all that man is changing the climate in dire ways.