Few swaths of Earth's oceans should be considered wilderness, according to a new global map.Credit: Brian J. Skerry/NGC/Getty

Only 13% of Earth’s oceans can now be classed as wilderness, according to a 26 July study in Current Biology.1

Researchers used global data on 15 human stressors of oceans, including fishing, pollution and commercial shipping. Areas were defined as wilderness if they showed little impact from these stressors (scoring in the bottom 10% of a measure of each), as well as a low aggregate score that combined these human activities and climate stresses such as ocean acidification.

Source: K. R. Jones et al. Curr. Biol. https://doi.org/csh5 (2018)

Most wilderness areas are in the open ocean and around the poles, far from human populations. Coastal ecosystems — which include centres of biodiversity such as coral reefs — make up just 10% of the wilderness area. Of all marine wilderness, just 5% is covered by marine protected areas (See 'Wild Oceans').

“High seas at the moment are a Wild West,” says author Kendall Jones, a conservation biologist at the University of Queensland in Brisbane, Australia. “It really highlights that those last few areas that are not impacted — how important they are.”

The United Nations is debating a high-seas conservation treaty, which should be signed by 2020.