2048

From Memory Alpha, the free Star Trek reference

[edit] Events

• Miles O'Brien and Kira Nerys briefly appear in San Francisco while attempting to locate the timeframe that Benjamin Sisko, Jadzia Dax and Julian Bashir materialized in. The version of 2048 they encountered was one of an alternate timeline, as O'Brien noted that it was "not the mid-21st century that [he] had read about in school." He added that "Earth history had its rough patches, but never that rough." (DS9: "Past Tense, Part II")

It is hard to believe that O'Brien would consider the nuclear holocaust and 600 million casualties of World War III, which was still ongoing at this point in the proper timeline, was merely a "rough patch." However, this can be simply explained by O'Brien pointing out that time was even 'rougher' then the World War III rough patch.

2047

21st century 2040s

2049