Scientists including very notable ones, are saying that the Earth is entering its 6th extinction event. There’s been 5?

https://www.youtube.com/watch?v=_7Vt4TEjcLY

Of the other 5 events they were,

https://www.youtube.com/watch?v=YLnlMmTW7S8

What can humans do to prevent or mitigate the worse?

NASA says climate change is disrupting the food chain in our biosphere and can change the life pyramid,