MIAMI: Areas of the world that are untouched by humans are disappearing, with some 10 percent of the planet’s wilderness gone since the 1990s, researchers said.

The study in the journal Current Biology raises concern about these vital areas that form the foundation for ecosystems, particularly in the places that have lost the most, the Amazon and Central Africa.

“We can’t restore or offset our wilderness. Once it is gone, it is gone,” lead study author James Watson told AFP.

“It is exactly the same as a species extinction,” said Watson, a researcher at the University of Queensland in Australia. For the study, researchers defined “wilderness” as “biologically and ecologically intact landscapes free of any significant human disturbance.”

They made a map of such areas at present, and compared it to a map made using the same methods in the early 1990s.

The result showed that about 20 percent of the world’s land area is currently wilderness, or about 11.6 million square miles (30.1 million square kilometers).

Most of that wilderness is in Australia, North America, North Asia and North Africa.

Comparing the old map to the new one showed that an estimated 1.3 million square miles — almost 10 percent of the wilderness area — has been lost in the past two decades.

The amount lost is equal to twice the land mass of Alaska, or about half the entire Amazon.

The study did not delve into reasons why, but Watson said it comes down to increased development by the planet’s growing human population. The worst affected areas were in South America, which has experienced a 30 percent decline in wilderness, and Africa, which has experienced a 14 percent loss.