Indeed there isn't a control experiment available for any global phenomenon, so you're right that we cannot state absolute proof in that sense.
What we can do is study cause and effect within the one framework we have. This gathered evidence can be reviewed by others who have made serious study of the same type of stuff.
Whilst we cannot talk in terms of absolute certainty that you refer to, we can - as someone with a scientific background, you will surely know this - deal in likelihoods and probabilities.
Einstein - the guy you say was right about everything - told us 'as far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality'.
So, by your definition, any science reliant on mathematics is not a science at all, and all belief in that science is akin to beleif in the tooth fairy. I wonder which would make you feel safest; living in a house designed and built by people who've studied and trained as strucural engineers or one done by that tooth-fairy believer?
As Jim says, there are vast swathes of evidence for anthropogenic climate change that are very difficult to scientifically refute. There is nothing of the sort for belief in god or papal infallibility.
It is simply crooked thinking to say that because somthing cannot be given as a complete 100% certainty it belongs in the same box as things that can never have any degree of certainty.
Other crooked thinking: 'What is accepted scientific fact today will be laughed at in 10 or a hundred years'. You imply that because some things we believe are true will turn out to be false, no thing we believe to be true can be trusted as such.
I'd point out that whilst some are laughed at, many scientific facts of 10 or a hundred years ago still hold true. Others that were mere theories have been conclusively proven. Newton's theory on gravity cannot be compared with other earths in a controlled experiment and was believed to be true a hundred years ago.
Of course, we don't know which are which today; that is no basis for discounting them all.
Further crooked thinking: 'I remember the scientists telling us an ice age was coming in the early seventies. I'm still waiting.' The implication here is that because some scientists once made wrong predictions about climate, therefore all future predictions about climate are wrong.
Aside of the logical flaw, in this case it's a lot more scientists. And almost all climatoligists are not predicting climate change. They are saying it is already here. The area for prediction is the degree of increase and the resulting impacts. When almost all sides - including those with a vested interest to deny it - say there is climate change and we see no other credible reason for the cause other than assorted human activities (not just CO2 emissions), it looks highly likely to me.
Further crooked thinking: in response to the posing of George Monbiot's four questions, you responded with 'George Monbiot, for all his good points is not someone I would rely on for any scientific debate.'
The implication here is that because the questioner is discredited, nothing they say is worth listening to. By that logic, if Hitler said water is wet that would make it dry.
The slur on Monbiot is unfounded - he's something of a stickler for hard scientific evdence, and gladly says things that many of his comradres decry including a recent call for increasing use of certain fossil fuels - but that's not the real point here. You used that slur to sidestep answering the questions.
You'd be hard pushed to find someone to seriously disagree with the four points of basic physics made in the questions.
1. Does the atmosphere contain carbon dioxide?
2. Does atmospheric carbon dioxide influence global temperatures?
3. Will that influence be enhanced by the addition of more carbon dioxide?
4. Have human activities led to a net emission of carbon dioxide?
Tell me which of these you can answer anything but 'yes' to. If these are the points you think are a 'red herring' can you explain why? They are the essence of understanding the likelihood of anthropogenic global warming.
'I am not arguing for or against the theory'; actually you are. You make repeated implications that because the theory can never be absolutely proven in a controlled experiment, it cannot be taken as anything more credible than 70s claims of ice ages or belief in the 'existance of god, santa claus, tooth fairy etc'.
'propogators of the CO2 glabal warming theory are convinced of it without overwhelming proof', indeed but they do have overhwhelming *evidence*, which is what sets them apart from those who theorise on the tooth fairy and friends.
Now, given this extremely high likelihood and the catastrophic results it threatens, how late would you like to leave it before reducing any of the things that appear to cause climate change?