A sudden change in the Atlantic Gulf Stream, which new research has linked to the mass extinction of dinosaurs, may happen again, many scientists fear.

The shift could be abrupt, and climate experts advise that we must continue to monitor the present warning signs, such as influxes of fresh water into the North Atlantic, and slowdowns of the Atlantic Gulf Stream.

A popular theory concerning the extinction of dinosaurs is that a sudden, external event, such as an asteroid hit or volcano eruption, led to the dino demise. But new research, published in Nature Geoscience and the journal Geology, argues climate was more to blame. The research determined that the greenhouse climate of the Cretaceous period experienced a sudden drop in global temperatures.