It’s not difficult to see how we are going to get to a position where the sun will scorch people’s flesh.
Firstly apart from are own Carbon Dioxide emissions over the last 100 years, you then have billions of tons of Methane going up into the atmosphere, Methane being about 21 times better at trapping heat. Although most of this is burnt off you still have massive amounts of Carbon Dioxide going into the atmosphere as a result of all the burning vegetation caused by the burning hail in Event 1 the Burning Hail.
There is also the Carbon Dioxide that is given off as a result of all the fires of Event 6 the Burning Sulphur.
Revelation Chapter 16 V 8 says:
The fourth angel poured out his bowl on the sun, and the sun was given power to scorch people with fire. They were seared by the intense heat and they cursed the name of God, who had control over these plagues, but they refused to repent and glorify him. (NIV)