As a physician and a grandmother, I understand the urgent need for radical, selfless sacrifice for our present and future world. I have traveled all over the world and always dreamed of spending my final years continuing to do what I love.

However, several years ago, while marveling at the bittersweet beauty of a receding glacier, I suddenly understood viscerally the kind of world in which my granddaughter would live. It saddened and frightened me so much that I gave up all recreational air travel then. I lost my ability to rationalize my own pleasures at the expense of the costs to others who will live beyond me.