Fresh Water
Fresh water is becoming scarcer in some US regions. Many mountainous states rely on snowmelt water as their water sources, and the amount of snow is decreasing as well as melting earlier in the season. Droughts can increased evaporation and changes precipitation patterns, thus impacting water levels in streams, rivers and lakes. Nearly 18 percent of the world's fresh water is found in the Great Lakes, which supply drinking water to a large region. Scientists expect lake levels to drop as the climate continues to warm up. Lake Superior is the largest of the five Great Lakes. The Great Lakes is 4.5 degrees F warmer than it was in 1980, and water levels in all of the Great Lakes have generally declined since 1986.