"The future has so much potential, we're closer to Star Trek every day" - Me, about 20 years ago
I was imagining more
Extreme weather events cause mass migration
Violent conflicts erupt due to displaced people, famine and water ... the conflicts are just one step short of a war (it's violent enough for many people to be killed but doesn't grow into a general war .... like Palestine on a continental scale)
Society breaks down in incremental steps over about 50 years