*I am sending this on behalf of Tom Wigley, who for some reason was unable to post. I will take this opportunity to say that I do think Eugene Gordon's comments shows a misconception of what science is about. When we use Newton's or Einstein's laws of motions to explain planetary orbits, we are constructing a model. Experiments and observations are aimed at allowing us to construct models. Science is largely about constructing mathematical models of the world that have predictive capability.*
Dear all. This is in response to Gene Gordon's skepticism. This is a bit peripheral to the geoengineering issue -- but his statements about the scientific method cannot go unchallenged. Here are some "experiments" (model tests) that have been performed ... Use best independent estimates of the historical forcings on the climate system. Run a model with these forcings. Compare the model response to the observed changes. Result: statistically significant agreement for surface temperature, tropospheric temperature, stratospheric temperature, height of the tropopause, atmospheric moisture content, etc. These agreements are not only for global-mean values of these variables, but also for the patterns of change -- a much tougher test. (All of this is in the peer-reviewed literature.) To go further, one can do the same "experiments" with other forcing possibilities -- such as solar forcing alone, or simply no forcing at all. The results here show no agreement -- i.e. the differences between the model expectations and the observations are statistically significant at very low p values (i.e., highly significant differences). I could phrase these statements in more formal statistical language, but the points do not change. A crucial aspect in these studies (referred to as "Detection and Attribution" studies) is the use of patterns of change. Just to give one example. anthropogenic forcing should cause the surface/troposphere to warm and the stratosphere to cool. Which is just what we observe. In contrast, positive solar forcing should cause both regions to warm, which is not what is observed. This is just one of the results that eliminates solar forcing as a major contributor to observed climate change. D&A work is a very stringent test of the science -- which the models pass. There are still uncertainties in the projections. But we can quantify these probabilistically, so that helps in the decision-making process. Tom. On Tue, Feb 28, 2012 at 9:56 AM, Eugene Gordon <[email protected]>wrote: > Thank you; models may help to explain the issues but not the science. Only > when you do an experiment for which you have predicted the results and the > predictions hold true and you do it enough times so that you have no doubt > achieved truth do you have a credible science. Until then it is interesting > but you cannot predict with any certainty and if you cannot predict then > what do you have? > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Alan Robock > Sent: Tuesday, February 28, 2012 12:32 PM > To: geoengineering > Subject: [geo] Climate sensitivity > > These two one-page articles are an excellent explanation of the issues: > > > http://www.pages-igbp.org/download/docs/PAGES%20news%202012-1(10-11)_Climate > %20sensitivity.pdf<http://www.pages-igbp.org/download/docs/PAGES%20news%202012-1%2810-11%29_Climate%0A%20sensitivity.pdf> > > Alan > > [On sabbatical for current academic year. The best way to contact me is by > email, [email protected], or at 732-881-1610 (cell).] > > Alan Robock, Professor II (Distinguished Professor) Editor, Reviews of > Geophysics Director, Meteorology Undergraduate Program Associate > Director, > Center for Environmental Prediction > Department of Environmental Sciences Phone: +1-732-932-9800 x6222 > Rutgers University Fax: +1-732-932-8644 > 14 College Farm Road E-mail: [email protected] > New Brunswick, NJ 08901-8551 USA http://envsci.rutgers.edu/~robock > > > > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/geoengineering?hl=en. > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/geoengineering?hl=en. > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
