Current levels of protection “do not even come close to required levels”, they said, urging world leaders to come to a new arrangement by which at least 30 per cent of the planet’s surface is formally protected by 2030.
Chief scientist of the National Geographic Society Jonathan Baillie and Chinese Academy of Sciences biologist Ya-Ping Zhang made their views clear in an editorial published in the journal Science.
They said the new target was the absolute minimum that ought to be conserved, and ideally this figure should rise to 50 per cent by the middle of the century.
“This will be extremely challenging, but it is possible,” they said.
“Anything less will likely result in a major extinction crisis and jeopardise the health and wellbeing of future generations.”
Most current scientific estimates have the amount of space needed to safeguard the world’s animals and plants at between 25 and 75 per cent of land and oceans.
There is an enormous amount of uncertainty due in no small part to incomplete knowledge about the number of species on the planet and the roles they play in ecosystems.
Nevertheless, the scientists dismissed current protection of 3.6 per cent of the oceans and 14.7 per cent of land as way off the necessary targets.
Researchers have warned of a “biological annihilation” as many of the world’s creatures are wiped out due to human impacts like pollution and climate change.
A recent study by BirdLife International revealed that several birds species, including the spix’s macaw, have gone extinct in the wild in recent years.
In the UK experts have warned that many of the nation’s best known species, including garden birds and hedgehogs, are facing alarming declines.
Of the areas that are currently designated as special protected zones, many are so-called paper parks that are not properly managed or are subject to intense human pressure.
A study published in Mayrevealed that a third of the land in the world’s wildlife sanctuaries and national parks – a total area of 2.3 million square miles – faces destruction due to human activities such as road building and urbanisation.
In 2010 at the Nagoya Conference of the Convention on Biological Diversity, the world’s governments agreed to aim for 10 per cent of coastal and marine areas and 17 per cent of land protected within a decade.
When leaders meet again in 2020 in Beijing, the scientists say that “given the evidence to date and the implications of an underestimate” they must make their next target far more ambitious.