Local modifiers for scorched earth have their own entry in the static modifiers file so that's where you'd have to go to change this for your own game if you wanted to.
If you meant these modifiers to be global for the nation (in which case -75% tax seems very harsh imho) that might be possible too. There is however no way to apply a global population growth modifier as far as I know.
If you meant these modifiers to be global for the nation (in which case -75% tax seems very harsh imho) that might be possible too. There is however no way to apply a global population growth modifier as far as I know.