Much of the point of individual action is really to communicate with other people and with political leaders and to demonstrate to them that we are willing to live lives which are less dependent on fossil fuels and we'll show you that now by changing our individual life to some extent but we want you to take action, political leaders, so that we aren't living in a society in which we're dependent on poisoning the future in order to maintain present lifestyles.

Our traditional systems of decision-making are just not up to preventing changes in fundamental earth systems that are driven by a constant barrage of individually negligible emissions of an invisible, odorless gas, by billions of people all over the world.

When it comes to climate change it's all the usual barriers: greed, mendacity, ignorance, short-sightedness and so on, manifest in the extreme power of corporations, the weakness of government, and the indifference of citizens.

Climate scientists think of nothing but climate and then express their concerns in terms of constructs such as global mean surface temperature. But we live in a world in which all sorts of change is happening all the time, and the only way to understand what climate change will bring is to tell stories about how it manifests in people's lives.

I think that by the middle of this century people will still be eating meat (though less), and their meat will mostly be produced in factories through synthetic processes, cell cultures, and so on.

I think the challenge of climate change in particular is the challenge for us to create and produce new norms for a new kind of world. And that's why I think as important as the issue of climate change is, it's even more important than it seems because if we can't evolve very quickly, new norms to deal with issues like climate change, we're not going to be able to survive in the kind of world we've created. So I think, really, the whole nature of democracy, of governance, of global community and of solving the kinds of problems of the 21st Century are really at stake.

Some philosophers have begun writing sympathetically about predator elimination as a way of reducing animal suffering. From an environmental perspective this is somewhere between naïve and potentially disastrous.