Pakistan, April 23 -- Every year, as April ripens into warmth and the trees shake off the last hesitation of winter, the world pauses, briefly, imperfectly, to remember something it too often forgets. Earth Day, observed on April 22, is not a celebration in the traditional sense. It is more like a moment of reckoning, a quiet knock on the door of human conscience, asking whether we have been good tenants of this extraordinary, irreplaceable home. Yet, when we hear words like "climate change" or "environmental crisis," something strange happens to the average person. The mind reaches for scale and is immediately overwhelmed. We think of melting glaciers, of cities sinking beneath rising seas, of billion-dollar green energy investments, of ...