The <a href="https://en.wikipedia.org/wiki/Pax_Romana">Pax Romana</a> was a period of relative peace, which lasted for approximately 206 years from 27 BC to AD 180. The peace was not absolute, though, and the historian Walter Goffart wrote, "The volume of the Cambridge Ancient History for the years A.D. 70–192 is called 'The Imperial Peace', but peace is not what one finds in its pages".

Similarly, there have been wars in the post-ww2 era, despite the era being relatively peaceful. The post-WW2 peace has also lasted for only about 72 years as of the writing of this question, making it only about 35% as long as the Pax Romana. In order to last as long as the Pax Romana, our peace would have to endure until 2151.

There are many things threatening peace, from seemingly perpetual unrest in the middle-east to an increasingly tense situation on the Korean peninsula. Yet, a major global conflict in the near future seems unlikely.

When predicting whether a major global conflict will occur within a longer timeframe, effects such as climate change and rising inequality (potentially due to AI?) might play a bigger role and the probability of conflict becomes more uncertain.