My question here is to which extend Ozone is blocking UV. I still dont know whether methane is absorbing
in the 170nm-750nm region, I have written an email with this question to people at the Spectral Atlas at MPG in Mainz
but if it does then the question of Ozone may become relevant. It is also that this example shows me that the
"folklore" that the high energy radiation (and there is a methane absorption in this spectral range!) is blocked before the troposphere needs eventually also be taken with a grain of salt.

That is for the case that UV absorption (and near infrared) largely alters the radiative forcing of methane I would eventually rather strongly disagree with whats written here:

>Although long-term mitigation of methane and hydrofluorocarbons are integral parts of 2 °C scenarios, early action on these species mainly influences near-term temperatures and brings small benefits for limiting maximum warming relative to comparable reductions taking place later.

and similar content in the other links you cited.