Humans have wrecked global biodiversity. Can we undo it?

Earlier this year, Harvard biologist George Church outlined his plan to produce elephant embryos that contain woolly mammoth genes. The news, big and even called fake, reignited a debate about whether and how gene editing can be used to bring back extinct species or at least some of their traits.

The context: The world's biodiversity, the sheer number of species and the diversity of traits, is under threat. For example, on our current trajectory of fishing, mining, damming and manufacturing, more than half of the planet's marine species may face extinction by 2100. At the same time, there is ongoing debate over how we should choose which species to try to save.

The questions: Where does the science and technology on de-extinction stand? Can and should this be done, and what do we stand to gain and lose? Here's what five researchers had to say:

• Joseph Bennett, biologist, Carleton University: Keep animals from going extinct in the first place
• Molly Hardesty-Moore, ecologist, University of California, Santa Barbara: Don't forget an extinct creature's ecology
• Ben J. Novak, biologist, The Great Passenger Pigeon Comeback: De-extinction is like any other conservation program
• Alejandro Camacho, legal scholar, University of California, Irvine: Wildlife laws aren't ready for the return of extinct species
• John Hawks, paleoanthropologist, University of Wisconsin-Madison: Bringing back Neanderthals