Neanderthals were pretty smart, and if we actively killed them off, then probably we did so in the same way that humans kill each other.

Well in the scientific there is virtually no debate over certain things. For example, that we are changing the world. Humans are changing the world very radically, very dramatically. Climate change, which I assume is one of the points you're alluding to, is at the heart of this.

We can't say that when x happens we get a mass extinction. To the extent we understand mass extinction, one has been caused by glaciation event, one has been caused by a massive climate change, and one has been caused by an asteroid. These events turn out to have no precedent.

In a poll commissioned by Time and CNN, two-thirds of American parents said they think that their children are spoiled.

Of the many species that have existed on earth - estimates run as high as fifty billion - more than ninety-nine per cent have disappeared. In the light of this, it is sometimes joked that all of life today amounts to little more than a rounding error.

People tend to focus on the here and now. The problem is that, once global warming is something that most people can feel in the course of their daily lives, it will be too late to prevent much larger, potentially catastrophic changes.

You've got to do everything, everything's got to be pointing in the same direction and you've got to really turn this whole economic engine from one that's based on fossil fuels to one that isn't.