OK....... I’ll tell the tale of my first hand observations.
I visited the Exit Glacier National park in Alaska. At about two miles out from the visitor center and former location of the glacier toe, there was a sign indicating the toe location in 1896. As you went along there were other signs lidicating the location of the receding glacier toe.
The US Government has been aware of warming and Exit Glacier melting for 125 years or so
Similarly. We went back packing in Glacier National Park in Montana. During hike prep we read of the various glaciers and of trails present where there were glaciers in the past. There has been considerable measured glacier degradation in the park. It is known and you can go see it
Bottomline....... there has been warming that has resulted in the degradation of known and closely watched glaciers.
The argument is not that there has been warming but has the cause been human related. The answer suggested by the very visible Exit Glacier degradation is no. There were no SUV’s or automobiles or electric power plants emitting green house gasses at the turn of the 2oth centaury. Humans are not the cause of the warming
BTW......... I recommend visiting the fantastic National Parks where the visual evidence is there to be seen by all. As Americans we are blessed with many sych wonderful natural places
Also Athabasca Glacier near Jasper, Alberta.