Some readers might recall a story from a couple of years of ago relating polar ozone depletion to cosmic rays and the subsequent failure of predictions made using that theory. The idea came from from a Qian-B. Lu (U. Waterloo), and initially seemed interesting (at least to those of us who were not specialists). Perhaps cosmic ray induced chemistry was playing some part in releasing chlorine from CFCs as well as the more accepted idea of heterogeneous chemistry on polar stratospheric particles? Lu’s predictions for increased polar ozone loss in 2008/2009 as a function of the low solar activity (and therefore higher CR flux) did not come to pass. Worse (for this idea), new analyses demonstrated that the hypothesized CR-induced CFC loss wasn’t detectable at all.
Undaunted, Lu continued to publish his ideas, though without really dealing with the criticisms, and indeed extending his scope to the issue of climate change as well as ozone depletion. He made a new claim that since CFC concentrations correlate better with temperature change, and that implies that CO2 can’t have an impact on climate. Very odd logic indeed. Unsurprisingly, his newest contributions have ended up in less and less mainstream publications. His last paper (Lu, 2010) was in the “Journal” of Cosmology – a recent online production that has been associated with a number of ‘fringe’ ideas (to be polite).
The paper before that Lu (2010, Phys. Rep.) has now come in for a real spanking from Grooß and Müller (2011) in “Do cosmic-ray-driven electron-induced reactions impact stratospheric ozone depletion and global climate change?”. From the abstract:
… Here we show that these arguments based on the CRE mechanism are inconclusive. First, correlations of satellite data of CFC-12, N2O and CH4 from ACE-FTS show no evidence of significant loss of CFC-12 as predicted by the CRE mechanism. Second, conclusions drawn about a possible CRE impact on the atmosphere, based on correlations of different observed atmospheric parameters, do not have a physical basis. Finally, predictions … based on these correlations are not reliable for either the ozone hole or global surface temperatures.
In my opinion the term ‘inconclusive’ is very polite indeed. The paper shows very clearly that there is no loss of CFCs through interactions with cosmic rays since if there was you’d see a change in the ratio of CFCs to CH4 or N2O (relatively long-lived gases) in the stratosphere. And you don’t. This was exactly the same (and completely valid) point made by the same authors in their rebuttal of Lu’s earlier paper (Müller and Grooß, 2009). However, since Lu obviously took no notice of that earlier criticism, it is impressive that Grooß and Müller took the trouble to rebut his claims even more thoroughly.
As we discussed recently, the role of providing rebuttals to bad papers in the literature is mostly thankless, but it is necessary. Hopefully for Müller and Grooß this is the last time they’ll need to.