Glaciers and Icebergs

Glaciers form in areas where more snow falls than melts each year. As snows build up, the weight of the snow presses on the layers below, changing them to ice. When the weight of the snow is great enough, glaciers begin to flow slowly downhill. Ice is added at the top of the glacier through snowfall. Ice is removed from the glacier by melting, sublimation, and the formation of icebergs. Recall that sublimation is the process of converting a solid directly into a gas.

Icebergs are large pieces of ice that break off when a glacier reaches the ocean. Many icebergs drift great distances from glaciers each year, creating a hazard to ships and ocean drilling platforms. Icebergs eventually melt as they drift into warmer water.

Fresh Water Resources

As the number of people on Earth increases, the limited supply of fresh water is becoming increasingly important. Nearly a billion people already go to sleep thirsty each night due to insufficient or inadequate water supplies. People in some parts of the world rely on groundwater aquifers that are drying up. Other people depend on runoff from glaciers that are melting. Some rivers, such as the once-mighty Colorado River, rarely make it to the ocean because most of the water is used by humans. One solution, though expensive, is to make fresh water from ocean salt water in a process called desalination.