Over 12,000 years ago, woolly mammoths roamed a vast Arctic tundra. At around 10 feet tall, they dominated the landscape. Their tusks could grow to four metres long.

And, soon, they could be walking the Earth again.

A team of scientists and entrepreneurs have started a new company to resurrect the woolly mammoth.  

The company, named Colossal, aims to place the beasts back in Siberia. It has received $15m in funding. 

The process of "reviving" a mammoth is down to gene editing. Colossal's team will edit elephant DNA, adding genes for mammoth traits like wiry hair and thick fat for withstanding cold. 

Within a few years, they could be producing embryos of these creatures. Before long, entire populations could be introduced.

Not all scientists are convinced. Bringing back creatures that lived in a vastly different environment - and keeping them alive - will be a huge challenge. 

If the team is successful, they will face questions. Is it right to produce an animal we know so little about? Who gets to decide where they live? How will they affect existing ecosystems? 

There are many supporters. George Church is one. A biologist at Harvard Medical School, he has been working with a small team on reviving mammoths for eight years. He has described the new company's success as a "major milestone", saying: "It's going to make all the difference in the world."

For him, this experiment goes far beyond scientific curiosity. It could help the environment, too. 

Woolly mammoths lived during the last ice age before they were wiped out by rising temperatures, evolving food supplies and human hunting 10,000 years ago. 

Now, the land where they once grazed is warming again. Church says mammoths could be the solution.

The modern tundra is covered in moss. When woolly mammoths were around, it was grassland. Research suggests mammoths helped control the moss.

Russian ecologists have already imported bison to control the moss. Dr Church believes revived woolly mammoths would do this more efficiently. 

The success or failure of the project could have further implications. It might mean reviving other species.

Perhaps the most famous extinct animal of all is the dodo, hunted into extinction in the 1660s.

One thing is certain: we won't have a real-life Jurassic Park anytime soon. DNA goes extinct after one million years, at which time the dinosaurs were long dead. 

Even so, the possibilities, according to Ben Shapiro from the University of California, are both "exhilarating and terrifying".

Yes: This is not just a scientific experiment. The mammoths could help stop the climate crisis. With the natural world struggling all around us, this is just what could be needed to boost it back to life.

No: It is wrong for humans to manipulate nature to this extent. And there are far simpler ways of fighting the climate crisis. Spending $15m on a problem that can be fixed more simply is an utter waste.

Or... This technology is potentially useful, but it can be put to better use. The genetic techniques could benefit animals like the white rhino by reintroducing diversity to tiny populations. With more than 20,000 living species currently threatened with extinction, we should be focussing our efforts on saving them.