The climate science is indisputable...the known physics requires that each tonne of new CO2 emissions will have a smaller impact than the previous tonne...there is no escaping the actual logarithmic relationship between atmospheric CO2 and global warming.....
The known climate science of global warming is not a mystery. It is well documented climate physics that just about every scientist agrees with. And for the layperson, it's not terribly difficult to confirm.
To do so, one needs the following:
1. A global temperature dataset
2. CO2 emission tonnes from 1850 to 1964 and tonnes from 1964 to 2014
3. A spreadsheet to make the necessary calculations and then plot the outcome.
These items were used to produce the adjacent chart. Five different time periods were chosen, then the warming (degree C) per CO2 tonne was calculated for each time period.
The resulting datapoints were then plotted and connected with a fitted trend (6th order).
Clearly, this actual climate science empirical evidence substantiates the known climate physics.
With this confirmation, one could assume that all warming since 1850 was due to human CO2 emissions, but then the logical conclusion is cast in concrete science - CO2's impact is shrinking towards zero, as observed, and likely will have even a smaller global warming impact in the future.
Note: The chart's fitted trend provides a sense of direction in the past but it has unreliable predictive qualities (if any). Why 1950-2013? Because the IPCC claims human CO2 is principal cause of warming since 1950. Why 1988-2013? Because in 1988, NASA's James Hansen testified that CO2 warming was accelerating and dangerous (it's been neither). Why 1997-2013? Because, it's been approximately 17 years with the 'paused' global warming. The 1850-2014 period assumes 17.5 gigatonnes of CO2 for first 7 months of 2014. Used 12-month HadCRUT averages to calculate deg/tonne.