Earth is on the brink of a "mass extinction event" which could be equivalent in scale to the one that killed off the dinosaurs 65 million years ago, a landmark study by an international group of scientists has concluded.

Researchers warned that deforestation, climate change, and overfishing have driven extinction rates to 1,000 times their normal level, Reuters reports.

Duke University biologist and conversation expert Stuart Pimm says that "time is running out" to avert the threat of mass extinction.

If the crisis is to be avoided, humans need to make large scale changes immediately, Pimm says.

"When you look at the range of unsustainable things we are doing to the planet – changing the atmosphere, global warming, massively depleting fisheries, driving species to extinction – we realise we have a decade or two," Pimm warned. "If we keep on doing what we are doing by the end of the century our planet will really be a pretty horrendous place."

The study compared historical extinction rates with contemporary data collected from around the world.

"We can compare [modern data] to what we know from fossil data and what we know from DNA data… DNA differences between species give us some idea of the time scale over which different species are born and die. When we make those two comparisons we find that species are going extinct a thousand times faster than they should be."

According to Pimm, the last time the planet faced such a significant extinction event was 65 million years ago, when, he says, a third to a half of all animal species on Earth died. "If we continue on our present course, that's how much we will lose," Pimm said.

The report notes that with the right intervention, the crisis could yet be averted. Conservation, education and "targeted preservation efforts" could slow down extinction rates, the report concludes.