Another large context by which the Shift Age will be framed relates to how we view, and live with, the effects of the 20th Century.
A Time Lapse Photographic Sequence of Change
It could easily be argued that more change and alteration occurred in the 20th Century than occurred in the prior 150,000 years that modern humanity has lived. The 20th Century, more than any other 100-year period in history, altered the landscape of the planet.
Imagine a theoretical time-lapse photographic sequence where at the beginning of each century since 1000 there was a panoramic photograph taken of the region where you live. Now flip through those images in order. There may or may not have been noticeable change through the first nine photographs through 1800, depending on where you live. But no matter the place, by the tenth photograph, in 1900, there was probably some noticeable change from the prior one.