butterfly effect
noun [ S ] uk/ˈbʌt.ə.flaɪ ɪˌfekt/ /ˈbʌt̬.ɚ.flaɪ ɪˌfekt/
the butterfly effect 蝴蝶效应，连锁反应
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. "混沌理论基于“蝴蝶效应”的概念，即由于系统根基不稳，即使起始条件的微小不平衡也会导致结果的巨大变化。
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。