I'd like to keep this as science based as possible. I'm not even sure if this sort of question fits this exchange. Is there a possible world wide affect that when triggered (by human/cosmological initiative) would make most if not all humans go nocturnal?
The effect on other creatures, plants and species preferred to be as minimal as possible. A few hundred species and some crops going extinct wouldn't matter. But if mass extinction can't be helped, well, we can explore how humans can adapt to that too.The technological level before this sudden change would be as of present.
If there could be some cultural/sociological/political change that can bring about the transfer from a diurnal to a nocturnal life, the incentives for such a change can be explored too. This would give the advantage of staying away from damaging existing global ecosystems and substance cycles.
I'm hoping that proposed changes would have humans and the new global ecosystem survive for eons rather than being on a timer till doom (like the case of our sun going missing), and something permanent, something we cannot fix within at least a century.