The Earth was small, light blue, and so touchingly alone, our home that must be defended like a holy relic. The Earth was absolutely round. I believe I never knew what the word round meant until I saw Earth from space.

Russian cosmonaut Alexey Leonov

What is the use of a house if you haven’t got a tolerable planet to put it on?

Henry David Thoreau

Climate change — I had that question, all you climate-change people. We just — you know, again, we knew that the economy was still the main thing.

Candy Crowley, on omitting a question about global warming during the second presidential debate between Barack Obama and Mitt Romney