"We know more about the science of global warming, the massive extinction of species, the lack of clean water, desertification, all those issues," she said.

The Great Spring brought woes of its own, storms, floods, massive extinctions and migrations to overthrow whole ecologies.

And they must have known that even if there were massive extinctions, they'd given the biosphere enough general resilience to recover.

Earth's had crashed again and again in massive extinctions.

Analysis of Lake Kivu's geological history indicates sporadic massive biological extinction on millennial timescales.

"These things are going to hammer our planet every 100 million years or so and produce a massive extinction until a species evolves that can do something about it."

The massive extinctions that ended the Paleozoic era caused extreme hardship for the surviving species.

Another massive extinction; another rally; another and another, though I think each is more weak and starveling: until the end.

Granted, massive extinction occurred and only a few original designs survived.

The massive extinctions that ended the Permian period and Paleozoic era caused extreme hardships for the surviving species.