The story of humanity’s interaction with the northern white rhino is one of the conservation movement’s grimmest tales of recent years. “In the 60s there were 2,500 northern whites left in central Africa,” said Paul De Ornellas of the Zoological Society of London. “Poaching brought that down to 30 by the end of the 20th century, and now to the last two.”

Last week the species’ last male, Sudan, had to be put down because of ill health, leaving only two ageing females on the planet as representatives of a creature that once roamed in its tens of thousands across Africa. It is a sad history which, most of the world assumes, is nearing its end.

But human ingenuity could yet save a species that has been brought to the brink of extinction. The plan, which involves in vitro fertilisation (IVF), stem cell science and gene editing, could also pave the way to rescue other animals at risk, such as the Sumatran and Javan rhinos.

“Humanity has brought the northern white rhino to the edge of extinction because it has slaughtered the animal for its horn,” said project scientist Jan Stejskal, a conservation researcher based at Dvůr Králové Zoo in the Czech Republic. “We have a duty to try to save it, no matter how hard that is going to be.”

But saving the northern white – a project that will involve scientists based in Germany, Italy, Kenya and the US – is controversial. Some conservationists argue that the resources used to save the species would be better spent on reducing the ecological threats to other creatures before they reach a critically endangered status. Other wildlife experts argue that such a complex approach to species preservation could lull conservationists into an unjustified sense of security.

The IVF plan involves creating embryos and implanting them in surrogate mothers from a closely related sub-species, the southern white rhino, which is not endangered.

“We have stores of frozen samples of semen taken from several northern white males that used to live in zoos in Europe,” said Stejskal. “What we want to do is thaw some of these samples and use them to fertilise eggs taken from the species’ last females. We could start that process later this year.”

The issue is urgent, he stressed. Najin and Fatu, the last two female members of the species, are old and the quality of their eggs is poor.

But a need for speed poses other problems. While it may be possible to create viable rhino embryos, implanting them in surrogate mothers poses difficulties. “Essentially, we have not yet learned how to implant rhino embryos into surrogate mothers in a successful manner and we need to perfect that technique to make sure we make best use of the embryos we create.” As a result, scientists may be forced to freeze any embryos they create and keep them until they have perfected their IVF implantation technology.

Think of what's spent on the Premier League. It would take a fraction of that to save a creature we hunted for its horn Jan Stejskal, conservation researcher

In addition, researchers are also considering creating embryos using sperm from northern white rhinos and eggs from southern white rhinos. “The resulting offspring will be hybrids but we may then be able to use standard crossbreeding techniques, like those employed in farming, to create a population that in the end would contain only northern white rhino genes,” said Professor Cesare Galli of Bologna University, another leading project scientist.

In the end, only highly advanced technologies may save the rhino, added Galli, in particular stem cell science. This involves researchers removing cells from frozen rhino tissue, which would be “reprogrammed” into stem cells that would then become sperm and eggs. So the species would be resurrected by taking skin cells from dead animals in order to create fully viable embryos. However, such procedures have yet to be developed and their use with rhinos lies years ahead.

Other rhino species have fared better than the northern white. “In Kenya, the black rhino population fell from 20,000 to 350 between the 70s and 90s but numbers have slowly improved thanks to anti-poaching efforts and now stand at 700,” said De Ornellas.

Even more striking is the story of the southern white. “By the end of the 19th century it was thought to be extinct thanks to hunting. Then 30 animals were discovered in South Africa. They were carefully bred and protected so that there are now 20,000 – making it the world’s most common rhino sub-species.”

Some conservationists suggest the story of the southern white’s remarkable recovery shows how wildlife funds need to be channelled into protection and not on expensive science. But this is rejected by Stejskal. “Think of the money that goes into the Premier League. It would only take a fraction of that to save a creature that we have deliberately hunted just for its horn. We have a duty to try to bring it back from the brink.”

He was backed by De Ornellas. “The saving of the southern white shows what can be done to rescue endangered animals,” he said. “However, the work that is now being done to preserve northern white rhinos should not be seen as being mutually exclusive to the conservation work that helped the southern. We need both approaches.”