What will the impact be if endangered glaci Glaciers act as reservoirs of water that persist through summer. Continual melt from glaciers contributes water to the ecosystem throughout dry months, creating perennial stream habitat and a water source for plants and animals. The cold runoff from glaciers also affects downstream water temperatures. Many aquatic species in mountainous environments require cold water temperatures to survive. Some aquatic insects--fundamental components of the food web--are especially sensitive to stream temperature and cannot survive without the cooling effects of glacial meltwater. Such changes in stream habitat may also adversely impact native trout and other keystone salmon species. What will the impact be if endangered glaciers disappear? Our coastlines would be very different. If all the ice covering Antarctica , Greenland and in mountain glaciers around the world were to melt, sea level would rise about 70 meters (230 feet). The ocean would cover all the coastal cities and land area would shrink significantly, but a few cities may be able to survive. When the glaciers disappear, those species will go extinct. This great melting will affect ecosystems and the creatures within them, like the salmon that spawn in meltwater streams. This is on top of the effects on the water that billions of people drink, the crops they grow and the energy they need. Glacier-fed ecosystems are delicately balanced, populated by species that have adapted to the unique conditions of the streams. As glaciers shrink and meltwater eventually declines, changes in water temperature, nutrient content and other characteristics will disrupt those natural communities.