Dear Judith,
I believe that the issue is a little bit more complicated than what you summarized.
First, it is not reasonable to request that so-called “climate scientists” be granted the special privilege of not being challenged by other scientists in different fields. This is highly inappropriate, in science in particular. Everybody has the right to challenge the claims of everybody else in science.
What makes a person a so-called “scientific expert” in a specific field against other people is not the tag-name than he/she has on his/her business card such as “Dr. Tim Brown, climate scientist.” But it is his/her capacity of showing that he/she does perform better in its profession than those who may challenge his/her understanding of a specific phenomenon.
History of science is filled of examples of people challenging the “consensus” in a specific discipline coming from another discipline. For example, the field of microeconomics between the 19th and 20th century was greatly developed by Vilfredo Pareto who strongly challenged the economists of his time. One may think that Vilfredo Pareto too was an economist by profession, but he was not. His personal formation was physics (!) and engineering (!). He simply succeeded in showing that his understanding of economical phenomena was superior to that of the professional economists of his time. In the same way, for example, the 11-year solar cycle was discovered by Samuel Heinrich Schwabe. One may think that Schwabe was a professional astronomer or astrophysics by formation. He was not. He was, by formation, a pharmacist (!) who simply succeeded in showing that his understanding of solar data was far superior to that of the professional astronomers. And innumerable examples like these exist in history.
If a scientist or a category of scientists are challenged by somebody else in their specific field of expertise, what they need to do is very simple. They need to show that they understand the phenomenon under discussion better that their opponent by using valid scientific arguments, or if they do not have valid arguments, they need to welcome their opponent’s ideas and acknowledge them and praise him/her.
What is happening in the specific topic of climate change and global warming is that a group of scientists, calling themselves “climate scientists”, has proposed an explanation based on a theory focusing on the anthropogenic GHG emissions. The problem is that, by just looking at internet, these scientists have failed to convince a lot of people with different expertise that their theory is solid and accurate. The challenge is mostly based on the analysis of the same data used by everybody, for example global surface temperatures, which the AGW critics claim to contain evident patterns which are not reproduced by the AGW theory.
For example, in my last publication in this field
N. Scafetta, “Testing an astronomically based decadal-scale empirical harmonic climate model versus the IPCC (2007) general circulation climate models” Journal of Atmospheric and Solar-Terrestrial Physics, in press. DOI: 10.1016/j.jastp.2011.12.005.
http://www.fel.duke.edu/~scafetta/pdf/Scafetta_models_comparison_ATP.pdf
I have shown that the global surface temperature appears to be characterized by a set of harmonics (~9.1, ~10-11, ~20, ~60 years period, at least). Although the physical causes of these harmonics are not fully understood (I have argued that these are astronomically induced harmonics), I could prove that none of the General Circulation Models (GCMs) used by the IPCC is able to reconstruct these oscillations, which make most of the observed climate variability.
I could also prove that GCM are currently overestimating the volcano signature by a significant factor, and I could show that the use of natural harmonics can be used to bind the net anthropogenic effect on climate to a magnitude that is about three times smaller than what the GCMs have assumed. Finally, I have shown that this harmonic model plus the corrected anthropogenic effect (which were all calibrated on the period antecedent 2000) is quite able to reproduce the global temperature standstill since 2000 and some other dynamical pattern observed in the temperature. On the contrary, all GCMs of the IPCC have predicted a steady warming during the same period.
So, at this point, the scientists who have promoted the AGW theory using a set of GCMs can do one of the two things: 1) contradict my calculations by proving that their models reproduce the oscillations observed in the temperature, or 2) acknowledge that these natural oscillations exist and that their physics is not yet implemented in their models, and that this missing physics needs to be developed yet (that is the science in not settled yet).
In the latter case, it cannot be claimed any more that CO2 does what the AGW advocates have thought because such a conclusion is based on climate models whose outputs have not passed the observational test. In fact, their GCM models have failed to properly reconstruct the observed dynamics and structure of the temperature data from 1850 to 2012, which these models were supposed to reconstruct, and since 2000, forecast.
Some of the figures I have produced are in my web site
http://www.fel.duke.edu/~scafetta/
Evidently, the fact that I am a physicist by formation is irrelevant; it does not make my results better or worse. In the same way, if other people develop arguments that questions ideas held by other people, the validity of their arguments is in the arguments themselves, not on the kind of doctorate one holds. So, criticizing the meditated opinion of a set of people by simply claiming that most of them are physicists working in fields different from climate science, is not valid.
These physicists very likely have sufficiently studied the relevant literature and concluded that the AGW theory is not as robust as the majority of climate scientists have claimed. The advanced reason is very simple: there exists a significant mismatch between the data and the predictions of the theory, everywhere.
There is nothing wrong for experienced physicists to express such a professional opinion; that is what physicists do all times.
I personally believe that climate scientists should try to search a constructive dialogue with people with a different scientific background. After all, climate science is a multidisciplinary science that truly requires people from multiple disciplines.
Departments of Earth Science should simply favor more multidisciplinary dialogue. For example, the sad costume typical only to the departments of Earth Science of the so-called “dis-invitation” of speakers that challenge the AGW needs to end once and for all. It simply isolates these departments from the rest of the world and gives to everybody only a clear message of scientific dogma and intellectual obtuseness. After all the students need to be educated in critical thinking, not in dogmatic indoctrination.
Indeed, instead of fighting against physicists (and everybody else) who simply express valid concerns, the departments of Earth Science should try to open their doors to them because these departments may also greatly benefit from the expertise and novel methodologies that physicists and mathematicians are able to develop.
Indeed, Departments of Earth Science should seriously consider hiring some physicists interested in climate phenomena.