The death of the dinosaurs was just one of five global events that saw millions of species wiped out. How do these events happen? And how can we stop it happening again?

For the last 10,000 years, Earth has been in the midst of yet another extinction event that is rapidly removing animals from our planet. 

Scientists define a mass extinction as around three-quarters of all species dying out over a short geological time, which is anything less than 2.8 million years, according to The Conversation. Right now, humans find themselves at the beginning of the latest mass extinction, which is moving much faster than any of the others. Since 1970, the populations of vertebrate species have declined by an average of 68%, and currently more than 35,000 species are considered to be threatened with extinction, according to the International Union for Conservation of Nature (IUCN). During the 20th century alone, as many as 543 land vertebrates became extinct, according to a research article in the journal PNAS. 

Are humans to blame? 

Ever since the beginning of the pollutant-pumping industrial revolution in 1760, humans have been the main contributor to Earth's current environmental crisis. From greenhouse gas emissions and ozone depletion to deforestation, plastic pile-up and the illegal animal trade, humans have actively stripped the world of some species and threatened many more.

There are those who argue that climate change and the extinction of animal species are a natural part of life, and in some ways that’s true. After all, the first five mass extinctions occurred without the presence of humans. However, the difference is the speed at which these mass extinctions happen.