I think that Ray has some important points to make about the nature of the scientific method.
It is absolutely correct that no means exist to reproduce the state of the atmosphere and its effect on our weather in the way that is required to do controlled experiments.
All we have are observational data.
Collection of direct weather data (particularly in terms of predicting long-term changes to weather and climate) is only a very recent phenomenon.
It is true that a lot of interesting work has ben done to try and look back much further to correlate indirect data from soil and ice samples, mud from the ocean floor etc to known weather phenomena of recorded history (a few thousand years at best) with some interesting results.
However, all the data so far is circumstantial.
The issue of CO2 and its effect on our climate is a case in point.
There is a definite correlation between the increase in atmospheric CO2 levels and and a change noted in our global climate over about the last century.
However correlation does not equal causation.
A lot more work needs to be done to prove that one observation might actually be the cause of another.
CO2 in the bigger scheme of things is actually a very weak greenhouse gas.
A lot of gases, methane is an example, are much stronger greenhouse gases.
Interestingly enough, in Australia, it has been proposed that we should get rid of all the cattle on continent and that we should farm kangaroos instead for meat.
The argument is that billions of farting cows are contributing to global warming because of the amount of methane these cows are collectively excreting.
However this bovine contribution to global warming is well and truly put in the shade by volcanic activity.
A single significant volcanic eruption extrudes more greenhouse gases into the atmosphere (not just methane and CO2) than 10 years of man-made greenhouse gas emissions.
Each year we see multiple large volcanic eruptions!
Now, in fact, I am not necessarily against limiting the use of fossil fuels and trying to limit the production of man-made greenhouse gases. The reason is that all the activities related to the whole process are damaging the global environment in very significant ways irrespective of the effect that may occur to the climate.
The point is that in multiple diverse ways humankind is collectively destroying our environment much faster than any change in climate might.
There is no doubt that the global climate has changed (even since I have been alive!)
However, as far as causation goes, as far as I am concerned the cause is not certain.
When I was in school and university classical scientific thought at the time was that things like climate and geology, if they do change at all, only do so very slowly and incrementally.
Current data is challenging that belief profoundly.
Again, the data is also circumstantial, but rather compelling, that climate and geology are actually pretty static - until they change!
So, change, when it occurs, may be pretty dynamic and dramatic rather than slow, incremental, and imperceptible.
Whether CO2 or any other so-called greenhouse gas is responsible for what we call climate change is still debatable.
Our climate has been warming and cooling since our planet has had an atmosphere capable of creating a climate and weather that is roughly equivalent to what we experience.
The truth is that we do not understand all the inputs that either maintain or change our climate.
There are lots of tantalising, and interesting, theories that explain more short-lived climate phenomena rather well but when applied to longer-term climate determination become much less certain (to the point of chance).
Even applying those factors that are known to play a role combined into the best weather and climate models running on the most powerful computer systems operational today still struggle to determine whether a particular location will get rain tomorrow, never mind next week!
The reason is simply that those models are still way too simplistic to model reality and the granularity of the data applied is still way too coarse not mention incomplete.
I have no doubt that rapid advances will be made. Computing power will allow more complex models, fundamental research will uncover more and more of the essential, but still unknown, drivers of our climate and weather, and the granularity of the data available will improve progressively.
In summary, I would say that there are many agendas across the world that are being pushed by what I call scientism. It is an unwarranted, religious-type, belief in the infallibility of science always to be correct and always to do the "right" thing.
Having been around the types who do the science all my adult working life I can only say that the degree of intrigue and politics that goes on makes traditional politics seem boring. Dispassionate, objective types they are not!
This is not all bad. Passion is as important in science as in any other endeavour. However, the same human foibles so evident in other disciplines, professions, and job descriptions are just as prevalent in scientific circles as any other. So mistakes are made, agendas are pushed that reek of palace politics (or worse) rather than rational thought. The "right" answer may be more a function of what is politically acceptable than the actual evidence. All of us can think of scientists who have been publicly humiliated and disgraced by their colleagues, not because they were wrong - but because they were right - it was just not accepted because it challenged the politics and dogma of the day (howsoever defined). This problem is not limited to the Middle Ages and the Inquisition, believe me, it is very prevalent today in the 20th and 21st centuries.
The scientism of today feeds into this appalling phenomenon because the relatively uniformed public feed into the debate on a political level rather than at the level where it needs to be - the actual data and the process by which it was obtained since this is the only way to actually gauge the significance of any conclusions being drawn. How many "climate dissenters" in the scientific community are allowed a voice right now? Does the actual data they are basing their conclusions on even get a look in? The labels "climate dissenter" or "climate change denier" are very much political ones designed to humiliate and destroy credibility. So, instead of the debate being a scientific one it becomes a matter of popular politics.
So, my suggestion is that while the issue of climate change deserves our attention we all need to be much more discerning in who and what we believe. At the level of what the general public has access to there are very few unbiased sources of information out there.
To use an analogy familiar to us photographers: the level of noise is not a good indicator of the strength of the signal!
Merry Christmas!
Tony Jay