And we know who was there.

This is our extinction event.

And these existed for tens of millions of years.

And they've tried over and over and over again.

Well, there are five major mass extinctions over the last 500 million years, called the Big Five.

We're going to save lives, but there's going to be a cost to it.

Carl Sagan's nuclear winter thing.

Here's sort of the end of that 10 years of work.

They range from 450 million years ago to the last, the K T, number four, but the biggest of all was the P, or the Permian extinction, sometimes called the mother of all mass extinctions.

Dinosaurs became extinct a very long time ago.

Dinosaurs died out a very long time ago.

And today, we are in a situation where we estimate that we've transgressed three boundaries, the rate of biodiversity loss, which is the sixth extinction period in the history of humanity one of them being the extinctions of the dinosaurs nitrogen and climate change.

So that's sort of the theme big, different and gone.

But we haven't witnessed a big asteroid impact, so this is a type of neo catastrophism, and it took about 20 years for the scientific establishment to finally come to grips yes, we were hit and yes, the effects of that hit caused a major mass extinction.

Don't you mean extinct ?

Extinction.

That's happened before.

I'll get them bugs!

In the '30s.

Many other ecosystems on Earth are in real, real danger.

And just as everybody got excited about it, bang!

We stand on the precipice of a dramatic moment of choice.

Extinct!

The ocean's dying.

Well, the earlier point is we interfered in a big way by making these animals go extinct, and many of them were keystone species, and we changed the whole ecosystem they were in by letting them go.

And what Penelope says here is even more true.

Mrs. Ardakani.

Kiwis are, and so are these hawks trapped near Antarctica.

Who made equal pay for equal work the law of the land.

And I'm not talking about losing diversity in the same way that you lose your car keys.

There's an upside to the story.

There's an ibex in Spain called the bucardo.

It appears to be a fungally related ailment.

Extinction looms.

Well, dinosaurs were big, different and gone.

You're looking at a great example here.

literally crumbling.

These are two creatures that were created in order to save endangered species.

I thought that deadly disease was extinct. Yes, it was wiped from the galaxy generations ago, but I have given it life once again.

Extinction is part of evolution.

Extinction is a part of evolution.

Elephants are in danger of dying out.

Well that's what happens in normal hybridization anyway.

And that, to a large extent, is what we want to do now.

Sick.