Premise: Many science fiction works have been set in the 21st century (years 2001 to 2100). With humanity now in the 21st century, many of the predictions of these works have so far been proven obsolete. This page lists only "predictions" regarding the 21st century, as opposed to contemporary accounts of the actual 21st century, which would be too numerous to list.
Hypothesis: many science fiction works have been set in the 20th century.