The days of exploration of Shackleton and Scott are long gone. Everything has been climbed, crossed, done. Now what we're exploring are the full boundaries of human endeavour. It's not physical - it's all in the head.

We need to save the Arctic not because of the polar bears, and not because it is the most beautiful place in the world, but because our very survival depends upon it.

I learned two basic lessons on Everest. First, just because something has worked in the past does not mean it will work today. Second, different challenges require different mindsets.

The right to have our environment protected for the benefit of present and future generations is our most important human right.

When I was born, the world's population was 3.5 billion. There are now 6.8 billion people on the planet. By 2050, that's expected to rise to 9.4 billion. What's more, the Earth's resources aren't growing; they're decreasing - and rapidly.

When I'm preparing for a swim, I imagine absolutely everything about it: the color of the water, how cold it is, the taste of salt in my mouth. I visualize each and every stroke.

The blues is also existential and offers a sense of mature reflection that enabled it to be the leitmotif of modern life.