Any astronaut can tell you you've got to do everything you can to learn about your life support system and then do everything you can to take care of it.

Use your power to do whatever it takes to secure for humankind an enduring place on this little blue speck in the universe - our only hope.

Even if you never have the chance to see or touch the ocean, the ocean touches you with every breath you take, every drop of water you drink, every bite you consume. Everyone, everywhere is inextricably connected to and utterly dependent upon the existence of the sea.

The image of Earth from space transformed our view of ourselves. It is maybe the most important image that exists - because we can see ourselves in context in a way that otherwise would be really hard to explain. It should inspire us to wonder about it, to want to know everything we can about it and do everything we can to take care of it.

We are not only warming the ocean and the planet as a whole, but we are also acidifying the ocean and changing its chemistry.

Our job is to keep what is working intact and not destroy what we have got.

When you think about the real cost of so-called cheap energy that has driven our prosperity to unprecedented levels, for some of us, to our horror, we've realized that this has the potential for burning brightly and then snuffing out.