Snow. A single word, for an infinite variety of water formulations, frozen in air. The study of snow is physics, chemistry, meteorology, anthropology, geography, poetry and art. It is hope – annually renewed. And it is history, too.Earth saw its first snowfall 2.4 billion years ago. The world''s oldest skis, made by hand five thousand four hundred years old, pre-date the pyramids of ancient Egypt. To humanity, snow has variously been an ally and an adversary; an inspiration to countless artists and a place of breathtaking tragedy and survival. But it’s always been there. And now it is melting.In 1927, the snow was already more than nine metres deep on Japan''s Mount Ibuki when a remarkable 230cm fell in 24 hours, bringing about the greatest depth of snow - 11.82m - ever recorded. Yet it is a fact today that, ironically not only has this mountain''s resort been forced to close due to lack of snow, most people in the world have never been near snow: never felt the soft crunch of snow underfoot, never held snow to see it melt in their hands, let alone stood on a pair of skis.As the seasons lose their rhythm, and whole landscapes risk vanishing, shrinking too our planet''s ability to reflect sunlight, Swedish environmentalist Sverker Sörlin urges that we take the time to look - really look - at what it is we’re losing, in all its multifaceted wonder. And to question, what comes next?