Humans are driving the loss of entire branches of the “Tree of Life,” according to a new study published on Monday which warns of the threat of a sixth mass extinction.

“The extinction crisis is as bad as the climate change crisis. It is not recognized,” said Gerardo Ceballos, professor at the National Autonomous University of Mexico, and co-author of the study published in Proceedings of the National Academy of Sciences (PNAS).

“What is at stake is the future of mankind,” he told AFP.

The study is unique because instead of merely examining the loss of a species, it examines the extinction of entire genera.

In the classification of living beings, the genus lies between the rank of species and that of family. For example, dogs are a species belonging to the genus canis — itself in the canid family.

“It is a really significant contribution, I think the first time anyone has attempted to assess modern extinction rates […]