Myth: Climate change has no specific meaning, beyond mindless obedience of “guidelines”

FALSE
Climate change (aka CAGW) was defined (wild guessed) in the 1979 Charney Report as a CO2 Equilibrium Climate Sensitivity (ECS) of +3.0 degrees C. +/- 1.5 degrees C.  or +1.5 to +4.5 degrees C.  

The IPCC adopted that definition in 1988 and kept using it until a few years ago when they arbitrarily changed it to +2.5 to +4.0 degrees C.  

Observations for the past 72 years suggests a WORST CASE ECS would be about +1.5 degrees C. with the actual ECS likely to be lower.

ECS is the guessed effect on the global average temperature caused by a 100% increase of the atmospheric CO2 level plus a water vapor positive 

feedback over the next 200 to 400 years (the IPCC gives the impression that ECS is for the next 50 to 100 years). 

In fact the IPCC has another wild guess about CO2 called the Transient Climate Sensitivity (TCS) for the next 70 years.  It is about half the widely publicized ECS, and buried in the detailed science backup to the IPCC Summary for Policymakers.  

The IPCC also uses an unrealistic high CO2 growth rate scenario called RCP 8.5 that suggests coal will be the primary fuel for generating electricity in the future. 

If one uses the climate models to estimate TCS, with the reasonable RCP 4.5 CO2 growth rate scenario, the prediction for the rate of global warming in the next 70 years is about the same as the actual global warming from 1975 to 2022, which was harmless.

You'll never hear about TCS with RCP 4.5 because that would not scare people.  The primary mission of the UN's IPCC is to scare people about CO2.

The atmospheric CO2 level did increase by about +50% since 1850, and the average temperature increased by about +1.1 degrees C. 

It's unknown how much of the temperature increase had natural causes or manmade causes.  The CO2 increase was 100% manmade. 

The +0.4 degree C. global warming from 1850 to 1940 had to be natural because the CO2 level increased very little, plus some portion of the +0.7 degrees global warming after 1940 is very likely to be natural too.

So "climate change' (aka CAGW) is very clearly defined.
The problem is the definition of CAGW does not match climate observations. Meaning the definition is baloney!

End of my tedious climate science lecture.
You can wake up now.

Ye Editor