Rumor is that James Hansen was so upset by CERN’s CLOUD experiment results that he and a gaggle of rabid environmentalists stormed the White House and demanded that cosmic rays be outlawed. Or something: it is always difficult to say what is on the collective mind of a mob.
Anyway, Hansen was shuttled off to the cooler and hasn’t been heard from since. And as of this morning, there is still no word from the White House on how cosmic rays could be blamed on George Bush.
Why the fuss? Jasper Kirkby and a swarm of co-authors from CERN have just seen their “Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation” published in Nature.
What Kirkby and his colleagues did was to build a tinfoil-wrapped container in which they simulated an artificial, high-altitude atmosphere in the lab. They let this replica atmosphere be bombarded by cosmic rays and noticed that cloud nuclei were created in the process. Why bother?
This: “Despite extensive research, fundamental questions remain about the nucleation rate of sulphuric acid particles and the mechanisms responsible, including the roles of galactic cosmic rays and other chemical species such as ammonia.”
The official synopsis (read it!):
We find that atmospherically relevant ammonia mixing ratios of 100 parts per trillion by volume, or less, increase the nucleation rate of sulphuric acid particles more than 100–1,000-fold. Time-resolved molecular measurements reveal that nucleation proceeds by a base-stabilization mechanism involving the stepwise accretion of ammonia molecules. Ions increase the nucleation rate by an additional factor of between two and more than ten at ground-level galactic-cosmic-ray intensities, provided that the nucleation rate lies below the limiting ion-pair production rate. We find that ion-induced binary nucleation of H2SO4–H2O can occur in the mid-troposphere but is negligible in the boundary layer. However, even with the large enhancements in rate due to ammonia and ions, atmospheric concentrations of ammonia and sulphuric acid are insufficient to account for observed boundary-layer nucleation.
Translation: cosmic rays cause clouds. Clouds, depending upon where and when they float, both cool and heat the climate. Ipso facto, cosmic rays affect the climate.
What is a cosmic ray? A ray whose origin is cosmic. I.e., a ray born in space, a region which includes the sun and beyond, and whose existences owe nothing to mankind. That is a long-winded way to say that our climate is, at least in part, regulated by forces completely outside political control.
So it curious that in its editorial accompanying Kirkby et al.‘s paper, Nature said, “Scientists on both sides of the debate welcome the findings, although they draw differing conclusions.” Do they? Welcome it, I mean.
There is already a “flap” over the comments of CERN’s director-general Rolf-Dieter Heuer:
I have asked the colleagues to present the results clearly, but not to interpret them. 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.
It is clear that cosmic radiation is, as Heuer says, one of many parameters. But it is far from clear just how important this parameter is. Is it the predominate driver of climate? A bit player? To say requires interpretation, which Heuer supposedly forbade.
But don’t let’s be too hard on Heuer. Another view of his advice is that his comments were fatherly, purely protective. I can tell you from personal experience how one’s career can be sunk into the toilet when one dares go against “the” consensus. Best to publish the results with no commentary and save yourself a ton of grief.
Too, these experiments were in the lab, not in situ. To say how cosmic rays influence the real climate will require observations on the actual atmosphere: expensive and time-consuming observations. The last word is not yet.
Still, old hands in climate science will recall the IPCC’s first report (AR1) eschewed entirely the sun’s role in the climate. The sun was just a bright yellow orb, supplying a constant, fixed, unvarying amount of radiation to Earth. Any changes in the climate caused by non-humans were due to orbital variations, and even these were barely worth mentioning.
Each subsequent report allowed a little more respect to the sun, but extra-human causes always played a minority role. It will be fascinating to see how “the” consensus incorporates CLOUD into AR5.
Best guess is that it will garner a footnote, possibly a sentence or two. The excuses for largely ignoring it will be two: as noted the experiments were in the lab and not the real atmosphere, and climatologists will not have had sufficient time to incorporate better cloud physics into their models. It’s a lot of work, you know.
So, while we’re waiting for more experiments and improved models, it’s better to be safe than sorry and claim that models that exist are more than good enough. That “tipping points” are just around the corner. That it’s “worse than we thought.” That “the science is settled.”
Anybody care to bet against me?