The sixth great extinction in the history of the planet Earth may be underway, and humans could be the underlying cause, based on a new report. 

Stuart Pimm of Duke University in Durham, North Carolina believes human activity may be driving species extinct 1000 times faster than the normal "background rate." This is ten times faster than most biologists had previously estimated. Without human activities, the study calculated about one out of every million species goes extinct each year. People are now responsible for driving that number up to between 100 and 1,000 per million, as per Pimm and his team.

"We start by asking how many species are known and how many remain undescribed. We then consider by how much human actions inflate extinction rates... [Areas] also suffer different levels of damage and have unequal levels of protection. How extinction rates will change depends on how and where threats expand and whether greater protection counters them," researchers wrote in the article announcing their research. 

The first great extinction occurred around 434 million years ago, at the end of the Ordovician era, when 60 percent of all plant and animal species went extinct. About 360 million years ago, climates that once favored reefs turned sour, plunging the world into the second great extinction. 

Paleontologists believe that between 80 and 95 percent of all species in the oceans disappeared in the third of these events. This one took place 251 million years in the past. Reefs nearly disappeared from the face of the earth, not to be seen for 10 million more years. Around 80 percent of all land vertebrate and half of all marine invertebrate species were lost at the end of the Triassic era, 205 million years ago. 

The fifth mass extinction is the most famous. For ten million years, many dinosaur species had died off, before the Earth was struck by a giant asteroid or comet, which wiped out nearly all large lifeforms on the land. Continents flooded up to 40 percent of some continents. 

This new research for Pimm updates an earlier investigation he helped produce in 1995. In that study, published in the journal science, the researcher now admits he overestimated the background extinction rate and underestimated the speed at which species are disappearing. 

Investigators believe more extensive data collection and additional conservation regions can help protect life on the planet. 

Research into vanishing species and how humans may be causing the sixth great extinction was profiled in the journal Science.