Conservationists have issued a demand for urgent international action after a major report uncovered an unprecedented crisis in nature that threatens to devastate the world economy and imperil humanity itself.

Only a global pact on the scale of the Paris Agreement on climate change will save the natural world from irreversible collapse, the World Wide Fund for Nature said after publishing a report showing a cataclysmic decline in global wildlife populations.

Global vertebrate populations have fallen by 60 per cent since 1970 as human activity destroys their natural habitats in grasslands, forests, waterways and oceans, the organisation said.

Until the turn of the 20th century, humanity’s consumption…