If we are to save humanity and the planet from the worst mass extinction of all time, worse even than that at the end of the Permian, we must stop at two degrees.

At 1.24 am on 26 April 1986 Chernobyl’s Unit 4 reactor exploded after staff disabled safety systems and performed an ill-advised experiment to check – ironically enough – the reactor’s safety.

We humans, one species of animal amongst millions, have now become the de facto guardians of the planet's climate stability.

You'd be forgiven for thinking that climate change means we'll have to sacrifice our creature comforts. But it doesn't have to be that way.

This is like playing Russian roulette with a Luger rather than a revolver. One bullet, one chamber - and we're pulling the trigger.

Human releases of carbon dioxide are almost certainly happening faster than any natural carbon release since the beginning of life on Earth.

Our evolutionary psychology preconditions us not to respond to threats which can be postponed until later.

I discovered science, and in the process I hope I became a better environmentalist.

If substantial methyl hydrate melt begins to occur in the Arctic Ocean basin, then the (carbon) accelerator will be jammed, and there will be nothing we can do to cut the speed of climate change.

Once the 'portals of the future close - in Amazonia, Siberia or the Arctic - we will find ourselves powerless to affect the outcome of this dreadful tale.

Conventional economic theory... counts the depletion of resources as the accumulation of wealth.

It is impossible to be successful and prosperous if you cannot organize people to achieve maximum results.

The evolution of the universe is both mirrored by and incumbent upon your own.

Now-a-days, men wear a fool's cap, and call it a liberty cap.

I don’t think I can ever go back to cocoa!

Love is its own rescue; for we, at our supremest, are but its trembling emblems.

I'm in shape. Round is a shape.

Hell is the place for people who did not live their lives according to the best of what was in them.

Two or three tons of rock can really get you down-and keep you there.

Walls aren't put in our life to stop us, they are there to test how much we really want somthing.

Conspicuously absent from the Ten Commandments is any obligation of parent to child. We must suppose that God felt it unnecessary to command by law what He had ensured by love.