Some of us have been sitting on the high perches of academe for many decades. It gives some perspective when new disciplines ride into town like some old fashioned preacher holding a bible, proclaiming hell fire and damnation, and totting a six-gun. Like many of the so-called social sciences, health science, computer science and numerous others, climate science did just that. Until very recently it could only, at best, be classed as an immature science.
Like many of the other 'cross over' disciplines that came into existence in the 1960's and 70's, it attracted the weaker and newer universities and a large number of academics who discovered an opportunity for a university career who would not have been short listed for appointment in any mainstream discipline. Students, enthralled by any discipline that didn't entail too much cerebral activity signed up as undergraduates and then, aided and abetted by supervisors who understood barely more than their students, registered for doctoral degrees. The result: doctoral dissertations based upon pillaged methods and techniques from established disciplines unsullied by any proper understanding of how they should be used. Who needs to know the subtleties of computation, modelling or data analysis when the examiners and referees are your supervisors' pals on the conference circuit?
In the feverish search for funding and recognition, the new disciplines, up against the old, had to make bold claims. A new discipline needs a new theory, something that sets it apart from the rest. In addition, some entrepreneurial academics were able through the conference circuit and by persuading other academics to join editorial boards started journals which rocketed in popularity as the hermetically sealed incumbents of the discipline talked to one another and gave one another credibility. They, through their self referential publishing in their own closet journals, were able to give those bold claims the gold standard support of being published in refereed journals. It still didn't alter the fact that they were embarrassingly deficient methodologically and empirically. One of the properties of bullshit is that it doesn't matter how much refereed deodorant you spray on it, it still smells of what it is - bullshit.
And so it was with climate science. But climate science hit pay-dirt, its boldest claim that humanity was about to destroy life as we know it became a very useful political rallying point as the dismal ideologies of the left smothered and subverted the nascent green movement in the decades around the turn of the century. It was also an easy idea to feed to the 24/7 media circus. That claim became larded with a moral imperative to do something to save our grandchildren. The problem is that the fledgling science became choked by opportunism and in such a climate any criticism was viewed as heresy. And there were heretics - academics, scientists, engineers and indeed scholars from many diverse disciplines who smelt a very fetid rat. They soon realised that the underpinning science was pretty straightforward; you don't need to be able to solve the Schrodinger Wave Equation to figure out how the greenhouse effect works. But, as soon as they questioned the clothing on the Emperor they were damned: 'not published in the pal reviewed literature', an 'oil company schill', 'not a climate scientist', 'not one of us', 'votes republican or conservative', 'not one of the 97%'..... The abuse rained in and only the old and wise with little to lose apart from the invitations to their alma mater's rubber chicken events for academic emerati were prepared to put their hands up and cry 'foul'.
However, the hard question began to be put and the data was not playing ball. The myth of consensus is gradually breaking down and there is a chance that at long last climate science can move on. Unfortunately, like bad case law, it is hard to get beyond the precedents set by earlier publications in the literature. Here is where the Internet and the sceptical community have done climate science an invaluable service. When criticism doesn't come from within, its falls upon the Steve McIntyres, Anthony Watts, and yes, even the Matt Ridleys of this world to put the boot in.
So, isn't it a given that human emissions of CO2 are raising global temperatures, destabilising our weather systems, elevating sea levels and turning the oceans into skin shredding, boil creating acid? Are we really like rabbits staring into the headlights of armageddon? Well no. What the science tells is that CO2 added to the atmosphere increases its thermal capacity, this causes the atmosphere to expand and in doing so the top of the atmosphere (which radiates heat away) gets a bit cooler. Because of that the atmosphere at ground level gets warmer. There is no real doubt that over the 20th Century the planet warmed and the best estimate puts that at about 0.8C. Part of that occurred in the early decades and cannot be attributed to human influences. So, the addition of another 120ppm of CO2 (from 280ppm to 400ppm) elevated temperatures by perhaps 0.5C. If we doubled the CO2 concentration to 560ppm that would imply an additional temperature increase of 0.7C from now. That's not much - but what happens if we keep on increasing CO2? Will temperatures rise exponentially and we will all be toast? Not quite, the addition of CO2 to the atmosphere has a logarithmic effect - the more you add, the less the impact. The uncontroversial bit is that adding CO2 to the atmosphere will have diminishing but positive warming effect.
The problem with the theory is that the climate is not well behaved. For the first 40 years of the last century there was a sharp rise in temperatures that is normally explained as a 'bounce' from the little ice age of 300 years ago. Over the following 30 years temperatures fell but with a significant reversal and rising temperatures for the next 30 years. Since the late nineties temperatures (both land, ocean and crucially satellite) have been (statistically) insignificantly different from zero. This variability over the instrumental period has not been in lockstep with the smooth increase in atmospheric CO2. So, the inescapable conclusion: CO2 is not insignificant but there are other powerful forces at play. The natural rhythms of the oceans, solar influences, volcanic activity, aerosols, orbital mechanics, albedo effects of changing patterns of polar ice and glaciation all play a part. The problem is that climate science with its myopic focus on CO2 and the impact of homo sap. has only just begun to get to grips with these more pedestrian issues. You don't get huge grants for investigating geo-thermal effects in the deep oceans. You do get huge grants if you can show that we are all about to fry ourselves.