How will the future judge us? Lead-tinged ice cores in Greenland bear witness of the iron age 3,000 years ago. Higher layers contain radioactive isotopes from nuclear tests in 1945. But based upon the geologic record, many scientists suggest the world-wide layer of human-manufactured plastic marks the arrival of the Anthropocene -- a new extinction event.

Industrialization has caused habitat loss and generated carbon dioxide that is pushing us into another era of cataclysmic climate change. Instead of entering a fresh period of glaciation, our planet is now destined for a hot-house climate that we have not experienced for 50 million years.

The slate will soon be wiped clean again, a fresh transition to an unfamiliar world. Missing will be ocean reefs, dissolved in acidic seas, and many marine animals now hunted to extinction or starved by oceans stripped of their resources. Gone will be many forests, birds, large animals and predators like lions, tigers, polar or grizzly bears. We too will change.

What connection will we feel for humans -- if they remain -- adapted to an ice-free hot-house world rigidly domesticated and ecologically simplified? Future humans will be physically different, perhaps living packed together in urban hives and stripped of human initiative. The future might be a nightmarish scenario from science fiction, like H. G. Wells's 1895 classic novel: The Time Machine.

But it might be an amazing place, where population and climate instability are controlled and humans bring back the wondrous creatures of the past. Future rich ecosystems may protect a world in equilibrium, where predators prey and a changing environment evolve in a dance that has been the central theme of life on Earth for billions of years.

What lantern that will show us the way? Only a few species will thread the needle of the next bioholocaust. Has science led us to become survivors -- or helpless victims?

There is no dangerous knowledge. There is only dangerous ignorance.