Ok, let's look at point 3, specifically:
"This is because, by chemical analysis, we can tell that the majority of this carbon dioxide has come from the burning of fossil fuels."

Can RL provide some details about this. Such as how often has this chemical analysis been done.
It seems to me that this kind of analysis if accurate enough could tell us many things which would be interesting and inform on many things other than merely "majority of this carbon dioxide has come from the burning of fossil fuels" and doing this at least yearly if not weekly/daily could be expected, therefore if this was the case I would expect lots of validation and literature regarding this.

Perhaps if RL doesn't have time to answer he would suggest a few keywords, that could be useful.

Another aspect is don't see a close relation to significant increase of human emission over the decades compared to the more or less steady increase in Global CO2. In other words if Human emission were more or constant instead exponentially increasing, this would seem to fit the Global CO2 increase.

A slightly different way to say the above is that people relying upon the idea that Human CO2 was significant affecting temperature and knowing that there was exponential growth in CO2 emission were predicting an acceleration of global temperature within a short period of time. And 10 years after such predictions, we have not seen this. Instead we have been offer some reasons why this hasn't happened, which essentially can boiled down reason for why this increase has been hidden.

Lastly, can anyone give a number to the increase of global temperature to say 50 or 100 ppm increase in CO2.
We have had about 100 ppm increase in CO2 in last 100 years, and obviously in more recent times we have had increase of 50 ppm of CO2. It seems to me that if CO2 was mostly responsible for an increase in global temperature, that with 50 ppm increase in the future, one could assign a round number as far as temperature increase.