MELBOURNE, Australia — Scientists are warning that if human beings continue to mine the world’s wildernesses for resources and convert them into cities and farms at the pace of the previous century, the planet’s few remaining wild places could disappear in decades.

Today, more than 77 percent of land on earth, excluding Antarctica, has been modified by human industry, according to a study published Wednesday in the journal Nature, up from just 15 percent a century ago.

The study, led by researchers from the University of Queensland in Australia and the Wildlife Conservation Society in New York, paints the first global picture of the threat to the world’s remaining wildernesses — and the image is bleak.

“We’re on a threshold where whole systems could collapse and the consequences of that would be catastrophic,” said James R. Allan, one of the study’s authors.