a situation in which an action or change that does not seem important has a very large effect, especially in other places or around the world

Chaos theory relies on the idea of the "butterfly effect", that even slight imbalances in starting conditions lead to huge final variations in outcome because of the fundamental instability of the system.

And so we had the butterfly effect that was US households defaulting on their loans quickly causing chaos around the world. 于是我们看到了蝴蝶效应，就是美国家庭拖欠的贷款迅速在全球范围内造成了混乱。