There is no likely in a scientific law. If enough CO2 is added to the Earth's atmosphere, it has to cause warming and the amount of warming can be determined rather accurately. The measurements of the IPCC tend to be conservative and beyond a tipping point, people lack the technology to stop it. There will be too much obvious positive feedback to stop it. It should be obvious, a resultant forces pushing something towards a tipping point lacks the capacity to prevent something tipping at some point. The vector of force only changes things in one direction.
There is no scientific law in the concept known as a greenhouse gas,
The concept is that CO2 absorbs 15 um photons, because that is the only window H2O left.
What is not known is how much effect that actually causes.
Lab experiments have failed to detect much change in power levels as CO2 levels increase,
although not much testing has been done in a century.
CO2 can under the right conditions (ground state) absorb a 15 um photon, but unless if collides with another
atom or molecule, CO2 takes a very long quantum time to get rid of that energy, and the entire time that molecule cannot
absorb any additional 15 um photons. This means a fixed quantity of CO2 would quickly become saturated,
and would be much less efficient in absorbing photons.
The prediction of the amount of warming CO2 can cause is not measured but strictly calculated,
no actual measurements back up the calculations. The accuracy is limited to the accuracy of the assumptions used in the calculations.
Also there does not appear to be any warming tipping points, but there likely is a cooling tipping point.
Were there a warming tipping point, it would have tipped during one of the 4 other inter glacial s, in the last 500,000 years.
Let review this positive feedback a bit, How long do you think the period is between the warming perturbation and say 60 % of ECS?
Hansen says 37.5 years! How much positive feedback would it take to make the 2XCO2 perturbation of 1.1C reach an ECS of 3 C?
that one is easy, 3/1.1=2.727 times the input.
The climate system is incapable of distinguishing the source of warming, all warming looks like an input to the feedbacks.
Hadcrut4 shows we have .288 C of warming before 1950, and total warming of .9 C.
Table 2 of NOAA's greehouse gas index, shows a 2108 CO2eq, of 496 ppm
this would place the 1950 CO2eq level at 306 ppm
NOAA/ESRL Global Monitoring Division - THE NOAA ANNUAL GREENHOUSE GAS INDEX (AGGI)
So (5.35 X ln(496/306)X.3)=.77C,
.78 C + the pre 1950 .288 C is 1.068 C.
There is no positive number we can multiply times the .288 C to get the total to be .9 C!
So ether the feedback is negative, or the forcing number is too high, or both.