Humans have destroyed a tenth of Earth’s remaining wilderness in the last 25 years and there may be none left within a century if trends continue, according to an authoritative new study.
Researchers found a vast area the size of two Alaskas – 3.3m square kilometres – had been tarnished by human activities between 1993 and today, which experts said was a “shockingly bad” and “profoundly large number”.
The Amazon accounted for nearly a third of the “catastrophic” loss, showing huge tracts of pristine rainforest are still being disrupted despite the Brazilian government slowing deforestation rates in recent years. A further 14% disappeared in central Africa, home to thousands of species including forest elephants and chimpanzees.
The loss of the world’s last untouched refuges would not just be disastrous for endangered species but for climate change efforts, the authors said, because some of the forests store enormous amounts of carbon.
“Without any policies to protect these areas, they are falling victim to widespread development. We probably have one to two decades to turn this around,” said lead author Dr James Watson, of the University of Queensland and Wildlife Conservation Society.
The analysis defined wilderness as places that are “ecologically largely intact” and “mostly free of human disturbance”, though some have indigenous people living within them. The team counted areas as no longer wilderness if they scored on eight measures of humanity’s footprint, including roads, lights at night and agriculture.
The largest chunk of wilderness in the Amazon basin shrank from 1.8m sq km to 1.3m sq km, while the Ucayali moist forests in the west of the Amazon, home to more than 600 bird species and primates including emperor tamarins, was badly affected. The trajectory of loss in the world’s biggest rainforest was “particularly concerning”, the authors warned, given it happened despite deforestation rates slowing.
In Africa, none of the lowland forest in the western Congo basin is now considered globally significant wilderness, the study found. WWF believes the area is possibly home to more gorillas and chimpanzees than other area in the world.
The study said that wilderness was being loss faster than pristine places were being designated as protected areas, at 3.3m sq km versus 2.5m sq km.
Professor William Laurance of James Cook University said: “Environmental policies are failing the world’s vanishing wildernesses. Despite being strongholds for imperilled biodiversity, regulating local climates, and sustaining many indigenous communities, wilderness areas are vanishing before our eye.”
The study said the reason was that such areas are “assumed to be relatively free from threatening processes and therefore are not a priority for conservation efforts”.
The ramifications of remaining wilderness being corrupted were wide-ranging and irreversible for both people and wildlife, Watson said.
“There are four reasons why we need to protect these places. One is biodiversity, the second is carbon, the third is the poorest of the poor are living in them, and the fourth is this is a reference point for nature, of pre-human environments,” he told the Guardian.
The Earth’s remaining wilderness areas are strongholds for many of the land-based mammals on the red list of endangered species, which was updated this week to reveal that four of the world’s six great apes are now critically endangered.
Losing forests in these areas could also affect leaders’ efforts to rein in greenhouse gas emissions to tackle climate change, the study said, because of the amount of carbon stored in trees and peat.
Rewilding plans by conservationists, similar to efforts to reintroduce wolves, lynx and other species to the UK, could also be harmed by the loss of wilderness, because the world risked losing a true picture of what certain ecosystems looked like.
“Without concerted preservation of existing wilderness areas, there will be a diminished capacity for large-scale ecological restoration,” the authors wrote.