Print[Narrator] Glaciers exist on all the continents except Australia. Mountain glaciers, in particular, are very sensitive indicators of climate change. Accumulation of snow and ice are called input, increasing the mass of the glaciers. Melting and calving as when a big chunk of ice breaks off the main glacier, are known as output and it decreased a glacier’s mass.
Many things affect the balance between input and output. For example, temperature, precipitation, humidity, wind speed, slope, and reflectivity are all factors that can affect this balance. So, as climate changes, the relationship between input and output also changes. This can alter the thickness of the glacier and its advance or retreat. But most glaciers are more sensitive to air temperature than anything else.
You’ve heard of global warming. This is a global increase in atmospheric temperature that many scientists believe is caused by an increase in heat-trapping gases in the atmosphere. These gases are sometimes called greenhouse gases because they trap heat in the atmosphere just like the glass in a greenhouse keeps the heat inside the greenhouse from escaping. Some of this increase in greenhouse gases is probably natural but some human activities seem to be enhancing the effect.
For instance, through fossil fuel use, an increase in the release of heat-trapping gases could lead to global warming which in turn could lead to glacial melting; and there is evidence of melting. Data suggests that since 1850, some alpine glaciers have lost between 30% to 40% of their surface area and about 50% of their volume. Similar findings have been reported in other glaciers around the world. Global compilations show that sea level has risen about 1/10th of an inch per year. That may not sound like a lot but, by the year 2100, sea level may rise almost two feet if this warming trend continues.
Ice serves many functions. During the arctic winter, the air is colder than the water. The ice helps to insulate the water from the atmosphere. Where there is no ice, there’s a huge heat flow from the water to the atmosphere, which causes the air temperature to go up. Ice also acts as a mass exchange, preventing ocean water from evaporating into the atmosphere and since ice is white, it reflects the sun’s energy, keeping the system cool.
Without ice, the temperature of the earth would likely increase, perhaps significantly. Even a rise of 2 to 4 degrees Fahrenheit could have a profound effect.