You can't equate observation with models, however the IPCC does a great job on inference.

If CO2 is increasing, which we know it is, how do we attempt to measure the effect of that CO2 on climate, if we don't attempt to correlate it.

If climate is not sensitive to CO2 then the models are are a WOFTAM.

If the models don't attempt to model Climate Sensitivity then they are still a WOFTAM.

* WOFTAM - Waste Of Flaming and Time Money

'"Climate sensitivity" is not an input to any model I know of. '

If it is Not an Input the it must be an Output.

But -
'Spread in model climate sensitivity is a major factor contributing to the range in projections of future climate changes (see Chapter 10) along with uncertainties in future emission scenarios and rates of oceanic heat uptake. Consequently, differences in climate sensitivity between models have received close scrutiny in all four IPCC reports.'

source : .ipcc.ch/publications_and_data/ar4/wg1/en/ch8s8-6.html

That is merely an extract.

Edit: Models aren't measurement they are supposition based on assumptions.

You were talking about the models and Climate Sensitivity weren't you? I could have sworn you were. But each time you lose an argument you just move on to another.

I give up. Climate sensitivity is about as basic as you can get.

Radiative forcing does nothing on its own. In conjunction with Climate sensitivity we may get a viable output; depending on your figure for Climate sensitivity.

It has about much effect as 100mm of rain. We need more for context. 100mm in 1 hour, 1 day, 1 week? Is the ground already saturated? Is it all runoff?

Edit: as well as other Climate parameters- humidity, temperature, wind velocity, wind direction, cloud cover.

'As in previous IPCC assessments, AR5 uses the radiative forcing
1
(RF) concept, but it also introduces effective radiative forcing
2 (ERF). The RF concept has been used for many years and in previous IPCC assessments for evaluating and comparing the strength of the various mechanisms affecting Earth’s radiation balance and thus causing climate change. Whereas in the RF concept all surface and tropospheric conditions are kept fixed, the ERF calculations presented here allow all physical variables to respond to perturbations except for those concerning the ocean and sea ice. The inclusion of these adjustments makes ERF a better indicator of the eventual temperature response. ERF and RF values are significantly different for anthropogenic aerosols due to their influence on clouds and on snow cover. These changes to clouds are rapid adjustments and occur on a time scale much faster than responses of the ocean (even the upper layer) to forcing. RF and ERF are estimated over the industrial era from 1750 to 2011 if other periods are not explicitly stated.
[8.1; Box 8.1; Figure 8.1] '

climatechange2013.org/images/uploads/WGIAR5_WGI-12Doc2b_FinalDraft_Chapter08.pdf


However it is clear from this and other references that Radiative Forcing is NOT a measurement but a calculation or even an estimate.

If this is not so please point me in the right direction where I can find Measurement by observation

from the link you provided-

"The simulated emission of these other gases is represented by curve B in Figure 2. "

So we simulate one figure subtract it from another figure and we get reality?

Gravitational force is a calculation, based on observation and measurement.

if the age for the Ice core data for CO2 is wrong, as has been postulated, where does that leave pre-industrial CO2 levels as a basis for calculating Climate Change?

How much does lee charge for tutoring?