I talked about this before. Back in the 1970s; there were two competing stories of human induced climate change -- global cooling driven by atmospheric stuff called aerosols and global warming driven by CO2.
The aerosols are not the stuff they used to put in spray cans that were destroying the Ozone layer.
These are particulates in the air made of pollutants from burning high sulfur coal, leaded gas, etc. Also dust and ash from volcanoes and droughts and so on ...
Besides global cooling, atmospheric aerosols caused acid rain, smog, burning rivers, and fish kill from water pollution and more.
Laws like Nixon's Clean Air and Water Acts cleaned up much of that mess.
This is not a return to the mean. It just means that aerosol driven cooling is no longer offsetting carbon dioxide driven global warming.
Climate scientists are discussing spraying the atmosphere to create aerosols as a sort of desperation measure to counter global warming.