If there is no great threat to a nation, unscrupulous leaders can still create fear among the people, and then use that fear to gain power. But the fear must be great, because it has to be powerful enough to convince most of the people to give up most of their rights to a dictatorship: hence the advent of doomsday scenarios.
If a political movement succeeds in convincing the citizens that there is some terrible fate ready to happen to them, like “global warming” or “climatic instability”, and illustrate these fears with notions of catastrophic floods, storms, and droughts, then the voters might be scared enough to turn over their civil liberties to politicians who promise to save them from these terrible threats.
Beware the politician who creates fear!