Climate change, global warming and other environmental disasters are pushing our planet towards another major ‘mass extinction’ event, believes scientists. And all this is mostly being caused by human activities.

These species include several types of mammals such as cheetahs, lions and giraffes, says a report published on Monday in the peer-reviewed US journal, Proceedings of the National Academy of Sciences (PNAS). “This is the case of a biological annihilation occurring globally,” said Stanford professor Rodolfo Dirzo, co-author of the study. “Several species of mammals that were relatively safe one or two decades ago are now endangered,” he added.

These species have already lost one-third of their habitat and nearly 40% of them, including rhinos, orangutans, gorillas and many big cats — are surviving on 20 percent or less of the land they once roamed.

Over the past few million years, there have been five more die outs wiping off species from the planet for good. What happened during the past five major extinction events?

1) Ordovician extinction

When: about 445 million years ago

Species lost: 60-70 percent

Likely cause: Short but intense ice age

2) Devonian extinction

When: about 375-360 million years ago

Species lost: up to 75 percent

Likely cause: oxygen depletion in the ocean;

3) Permian extinction

When: about 252 million years ago

Species lost: 95 percent

Possible causes: asteroid impact, volcanic activity;

4) Triassic extinction

When: about 200 million years ago

Species lost: 70-80 percent

Likely causes: multiple, still debated;

5) Cretaceous extinction

When: about 66 million years ago

Species lost: 75 percent

Likely cause: asteroid strike.

All these were natural catastrophes, and there was no way to prevent or reverses them. But now, ever since humans started walking on the planet, they started to take control and bend everything to suit their needs. But in the process they’ve overlooked Mother Nature so much that now the climate has become imbalanced and inappropriate for other species and even humans to survive.

According to Gerardo Ceballos, lead author of the study, and a professor at National Autonomous University of Mexico, “The massive loss of populations and species reflects our lack of empathy to all the wild species that have been our companions since our origins.”

Scientists claim that even the creatures that did survive the previous mass extinctions, such as turtles, crocodiles and frogs, and sea creatures like sharks, starfish and sea urchins are now on the verge of extinction with the rise of one species- the Homo sapiens.