They reached the figure using an advanced mathematical model which they believe is the most accurate ever.
Previous estimates ranged from three million to 100million.
The Canadian researchers hope their ‘telephone book’ for the planet will help find undiscovered species and quantify how many are being lost.
Zoologists and botanists have been cataloguing species for 250 years, but so far only 1.2million have been logged. Each year 6,000 are discovered, but even at that rate, it would take another 1,200 years to find them all.
The authors reached their total using a model based on known species groups. Each was divided into categories, then re-divided again and again into theoretical sub-categories. Read More