The world risks losing new medical treatments for osteoporosis, cancer and other human ailments if it does not act quickly to conserve the planet's biodiversity, a senior United Nations environmental official said Wednesday.

Earth's organisms offer a variety of naturally made chemical compounds with which scientists could develop new medicines, but are under threat of extinction, said Achim Steiner, executive director of the U.N. Environment Program.

"We must do something about what is happening to biodiversity," Steiner told reporters. "We must help society understand how much we already depend on diversity of life to run our economies, our lives, but more importantly, what are we losing in terms of future potential."

Steiner was announcing the conclusions of a new medical book, Sustaining Life, on the sidelines of a UNEP-organized conference in Singapore. The book is the work of more than 100 experts, its key authors based at Harvard Medical School's Center for Health and the Global Environment, and it underscores what may be lost to human health when species go extinct, Steiner said.

"Because of science and technology … we are in a much better position to unlock this ingenuity of nature found in so many species," he said. "Yet, in many cases, we will find that we have already lost it before we were able to use it."

One example is the southern gastric brooding frog, or Rheobactrachus, which raises its young in the female's stomach. It was discovered in the Australian rainforests in the 1980s.

In other animals, the young would have been digested by enzymes and acids in the stomach. But preliminary studies show the baby frogs produced a substance or a range of substances that inhibited acid and enzyme secretions and prevent the mother from emptying her stomach into her intestines while the young were developing.

Research on this species of frog could have led to new insights into preventing and treating human peptic ulcers, but such studies could not be continued because the two species of Rheobactrachus had become extinct, according to the book.

Steiner said the book looks at seven groups of threatened organisms for potential or known medical value: amphibians, bears, cone snails, sharks, non-human primates, horseshoe crabs and gymnosperms, a type of plant life.

Last year, more than 16,000 species were labelled as threatened with extinction on the Swiss-based International Union for Conservation of Nature's Red List of Threatened Species.