In some areas, rain could make up the difference in the snow deficit, with rain increasing even as snow decreases. But other areas face a more challenging future. In 32 of those drainage basins, snowmelt is the primary source of water for the 1.45 billion humans that live there. Relying so exclusively on that single source of water means that a dry or warm winter could have disastrous consequences in the future. Among the areas at risk are the drought-stricken American West, areas of Europe from Portugal to Italy, countries in Asia, Morocco, and perhaps most worryingly, areas of the Middle East, including Syria, and parts of Saudi Arabia and Iran. Adding additional stress to a volatile region is a worrying issue for international security.