World is facing ‘mass extinction’ event, experts warn – and we are to blame

Earth is facing a ‘mass extinction’ event, the sixth in our planet’s history – and human beings are solely to blame, an expert has said.

The current rate at which species are going extinct is 100 to 1,000 times greater than a few centuries ago, based on data from a new World Wildlife Fund report.

Based on that data, Earth has entered a mass extinction event, and the blame is squarely at our feet, says Louise McRae from the Zoological Society of London.

McRae told Australia’s ABC radio, ‘We can put the cause down to humans in some form or another.

‘We looked at what was threatening these populations and the biggest cause was loss or fragmentation of their habitat, that’s the primary cause and the driving force of that is conversion of land for agriculture.’

Research this year suggested that we’re exterminating species so fast that it will take our planet five million years to evolve back to our current level of biodiversity after the next 50 years, according to Aarhus University researchers.

It could take up to seven million years to evolve back to the level of biodiversity found before modern humans evolved, the researchers warn.

The researchers simulated different rates of evolution and extinction to come up with different scenarios – warning that some species can take entire branches of the evolutionary tree with them when they become extinct.

Matt Davis from Aarhus University says, ‘It is much easier to save biodiversity now than to re-evolve it later.’

The researchers drew lessons from previous extinctions, such as the extinction of Pleistocene ‘megafauna’ after the last ice age.

Davis says, ‘Large mammals, or megafauna, such as giant sloths and sabre-toothed tigers, which became extinct about 10,000 years ago, were highly evolutionarily distinct.

‘Since they had few close relatives, their extinctions meant that entire branches of Earth’s evolutionary tree were chopped off.

‘There are hundreds of species of shrew, so they can weather a few extinctions. There were only four species of sabre-toothed tiger; they all went extinct.’