Egads. EGADS. Epic fail.
You fail to understand the paragraph you keep citing. Their claim is not that CO2 is specifically and maximally responsible for 1.2C, and the remaining 3C comes from "clouds." It's that the simplest possible models suggest an increase of 1.2C. However interactions between infrared radiation (commonly known as heat) and clouds produce unpredictable results and various feedback effects. Meaning all of that range is due to CO2 and feedback effects.
Meanwhile: When they reviewed Svensmark's theories in the 3rd and 5th Reports, they found the effects of cosmic rays to be negligible.
Oh, and CR is not a feedback. It's a type of forcing. And one that has a near-zero effect on climate.
Thus, it is NOT acceptable to claim that any reading of the IPCC documents support the claim that Svensmark's theory explains up to 3C of warming. First and foremost, they explicitly ruled that out. Second, Svensmark's theory has nothing to do with the interactions of clouds and heat.
To put it another way: Your interpretation requires a stupendous amount of cherry-picking.
Are you not looking at the graph? There's a component, labeled in plain English, as CHANGES IN SOLAR IRRADIANCE. That's what Svensmark claims is happening. It's near zero.
Read the graph, it pretty much tells you what you need to know about this debate over CRs:
• Solar irradiance (and CRs) have almost no effect on climate change.
• When we break it down by emissions type, CO2 is the single largest component in radiative forcing
• Huge amounts of radiative forcing are now due to human activity.
You're welcome.
Lots of words, without a lot of understanding!
The 1.2 C is the warming from forcing for 2XCO2, and almost everyone agrees the number is between 1 and 1.2 C,
(Technically the 1.2 C is from when they thought the energy imbalance from 2XCO2 would be 4 Wm-2,
the current number is 3.71 Wm-2, and I have seen numbers as low as 3.44 Wm-2)
The 3 C is the uncertainty applied to the amplified feedbacks (3 C is the difference between 1.5 and 4.5C)
I think you need to get your story lined up.
Clouds can both slow down cooling, and prevent energy input,
It does not get as hot on a cloudy day, but cloudy nights do not get as cold as clear nights.
The models do not handle clouds well, hence the uncertainty.
Svensmark's theory involves one of the mechanisms in the formation of clouds,
and it's not related to solar irradiance, and saying so only points out your poor understanding of the theory.
The way I understand it, during periods of high numbers of sun spots, solar winds stop more
cosmic rays from entering the Earths atmosphere, and fewer clouds are formed.
fewer sunspots, less solar winds, more clouds.
While I an not sure that Svensmark is on the right track, it is a viable theory.
Part of the traction of AGW, was that no other theory could explain the temperature changes,
I disagree, several other theories explain the temperature changes, and they are all valid until disprove.
We currently do not have enough data to disprove anything.
The simplest theory is that most of the observed warming is Anthropogenic, in as much as people with
vested interest control the data sets. Selecting stations that show the warming to support their theory.
(That type of warming is Anthropogenic also.)
I think there was actual warming in the 20th century, but much of it could simply be natural of simple CO2 forcing.
We also passed legislation that cleared the skies around the world, clearer skies, more energy in!
I have not found good data on how much solar energy was reaching the ground in say 1970 vs 2017.
There are also clear cycles in the climate, some long, like the ice ages, some short like the El Ninos,
how the many cycles interfere, could cause a host of unknown results.
