Atheist - “Why do some people disbelieve the current scientific consensus regarding e.g. evolution or man-made global warming?”
With all due respect, conflating the consensus on evolution with man-made [anthropogenic] global warming (hereafter AGW) is disingenuous.
First of all – what do you mean that there is a consensus on AGW? The statement posed is far too simplistic since the matter is much more nuanced that that. For instance, if you're referring to the Cook et al study which concluded that 97% of scientists agree that AGW is happening and is primarily the fault of mankind's activities, then that study has been thoroughly discredited and shown to be entirely fraudulent. In fact, when the study was done again – but this time with proper checks and balances – it showed that less than 3% agreed with the premise that AGW was happening and was primarily the fault of mankind's activities.
An example of why the question is a nuanced one is as follows. Take the following two statements:
1. It likely that AGW accounts for at least half (ie. the majority) of the observed warming.
2. AGW poses an imminent danger to mankind.
I read somewhere (I shall try to dig out the reference) that around 70% of scientists (ie. not necessarily climate scientists, just scientists in general) agree with statement [1]. But less than 10% agree with statement [2]. Therefore, when we read headlines like, “There is consensus amongst scientists about AGW”, that in and of itself is meaningless. Just because people agree that something is happening, it does not follow that the something in question is dangerous and/or is a thing that should be mitigated against at colossal economic expense. The mainstream media has quite successfully managed to conflate statement [1] with statement [2], resulting in the public thinking that an overwhelming majority of scientists think that AGW is happening and is a dangerous threat to mankind when this is simply not the case.
As an aside, I have noticed in the last few years that every January, the BBC fly a small news team out to Antarctica to film melting glaciers and sea ice breaking up. They show the footage with a doom-laden narration that suggests (but does not explicitly say) that this is AGW in action. What they never say is that January in Antarctica is high summer since they're in the Southern Hemisphere. They lie by deliberate omission. It's an excellent way to mislead an audience that they hope are too stupid to notice. Funny how they never report on the ice forming in Antarctica in June...
But I digress.
Second, there is the problem with the basic principles of scientific enquiry that are routinely ignored when it comes to AGW. Richard Feynman puts it best:
https://bit.ly/3bmlG5z
In climate science, observed measurements are routinely ignored and/or marginalised in favour of computer models. In climate science, the mantra seems to be, “If the model doesn't agree with the observations, alter the observations”. Alterations of empirical data gathered from climate stations is now routine. In order for the present to appear to be warmer than the past, historical data is manipulated downwards, making the past appear cooler and the present warmer. Original data is then destroyed.
But that's another matter for another day.