(click on above for original/source)
That is a picture of an area close to Pittsburgh at high noon in 1948. The pollution from all the nearby industrial sources has blocked the sunlight (and solar warming).
This new study suggests that at least some of the modern warming may be a result of the EPA's (and other national governments) clean air regulations.
If true, it would be ironic that government bureaucrats are the ones most responsible for the global warming hysteria being blamed on colorless CO2.
The science is most definitely not settled; and, never forget the ever present law of unintended consequences from good intentions.