The absence of any major volcanic eruptions post-2000 raises some serious questions regarding the results of this study. One simply cannot look only at one ‘part” or factor (e.g. particles) at a time in atmospheric chemistry and physics and expect the results to represent the “whole.”
Gödel’s incompleteness theorems suggest that no matter how much climate mathematical modeling one does of the parts, it cannot reproduce the “whole.” The “whole” is always much more than what the sum of the “parts” suggest. And in this case the global climate is much, much more than what any mathematical modeling of any part of it (e.g. volcanic particles) suggest, and always will be. Observational science gives us an indication of the physical state of the “whole.” Mathematical modeling cannot do this. And this is why observational science should be preferred and supplemented with modeling rather than the other way around (where modeling is primarily considered).
Lastly, I am always bewildered when I see a paper (or in this case a letter) loaded with coauthors (or signatories), in this case 16. It leaves me with the impression of scientific bullying – the paper with the most coauthors must be the correct one (or perhaps just the politically correct one). But the number of coauthors is irrelevant to the validity of the analysis and likely says more about “group think” dynamics than anything to do with the science itself.
D.A Ridley, S. Solomon, J. E. Barnes, V.D. Burlakov, T. Deshler, S.I. Dolgii, T. Nagai, R.R. Neely III, A.V. Nevzorov, C. Ritter, T. Sakai, B.D. Santer, M. Sato, A. Schmidt, O. Uchino and J. P. Vernier. Total volcanic stratospheric aerosol optical depths and implications for global climate change. Geophysical Research Letters. DOI: 10.1002/2014GL061541
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