Includes bibliographical references and index.

As the planet warms, winter is shrinking. In the last fifty years, the Northern Hemisphere lost a million square miles of spring snowpack and in the US alone, snow cover has been reduced by 15-30%. On average, winter has shrunk by a month in most northern latitudes. In this deeply researched, beautifully written, and adventure-filled book, journalist Porter Fox travels along the edge of the Northern Hemisphere's snow line to track the scope of this drastic change, and how it will literally change everything—from rapid sea level rise, to fresh water scarcity for two billion people, to massive greenhouse gas emissions from thawing permafrost, and a half dozen climate tipping points that could very well spell the end of our world. This original research is animated by four harrowing and illuminating journeys—each grounded by interviews with idiosyncratic, charismatic experts in their respective fields and Fox's own narrative of growing up on a remote island in Northern Maine.