Icebergs in the Southern Ocean Click on image for full size (21 Kb) Ute Kaden/PolarTREC

Melting Ice Causes More Warming: Ice-Albedo Feedback
The albedo of snow and ice is very high, so approximately 90% of incoming solar radiation is reflected. As the planet warms and more snow and ice melt, the darker-colored open water and land surface absorb more incoming solar radiation, and then release the heat to the atmosphere, causing more warming. According to a recent scientific study that used computer models to predict the future of Arctic sea ice, there may be no more sea ice left in the Arctic Ocean during summer within the next few decades. "As the ice retreats, the ocean transports more heat to the Arctic and the open water absorbs more sunlight, further accelerating the rate of warming and leading to the loss of more ice," explains Marika Holland, a scientist at the National Center for Atmospheric Research. "This is a positive feedback loop with dramatic implications for the entire Arctic region."

Melting Permafrost Releases Greenhouse Gas
As permafrost soil thaws due to global warming, carbon trapped within the soils is released as methane, a powerful greenhouse gas. The carbon became trapped when the soils froze during the beginning of the last ice age in the Pleistocene. The methane released to the atmosphere causes more global warming. Jeff Chanton, a Florida State University scientist who researched methane released from Siberian permafrost, explains that, "because the methane now emitted in our study region dates to the Pleistocene age, it's clear that the process, described by scientists as 'positive feedback to global warming,' has led to the release of old carbon stocks once stored in the permafrost."

Less Ice on Land Causes Sea Level Rise
Sea level has been rising about 1-2 millimeters each year as the Earth has become warmer, which has increased the rate of melting glaciers and ice sheets and expanded seawater with the added heat. If all the ice on land including the large glaciers and ice sheets in Antarctica and Greenland melted, global sea-level would rise about 80 meters, but that is very unlikely, especially all at once. However, certain glaciers and ice sheets are particularly vulnerable because global warming has caused them to be less stable, to move faster towards the ocean, adding more ice into the water, which causes sea level to rise. These areas with less stable ice include the Greenland Ice Sheet and the West Antarctic Ice Sheet. If the Greenland Ice Sheet melted or moved into the ocean, global sea level would rise approximately 6.5 meters. If the West Antarctic Ice Sheet were to melt or move into the ocean, global sea level would rise approximately 8 meters.

Icebergs in the Southern Ocean Click on image for full size (21 Kb) Ute Kaden/PolarTREC

Most of us do not live in polar regions. We do not come in contact with icebergs or ice sheets very often. Most of us have only seen these things in photographs. However, no matter where you live, the snow and ice of the Earth’s cryosphere has an impact on your climate.

Recent changes in the cryosphere have had a major impact on global climate. This is because the cryosphere is an important part of the Earth system and because it is so interconnected with other parts of the Earth system. Scientists are currently studying just how much the frozen places on Earth affect global warming. Below are some of the ways that the cryosphere has been affecting climate change through interactions with other parts of the Earth system and feedbacks that increase the rate of global warming.

Melting Ice Causes More Warming
When solar radiation hits snow and ice approximately 90% of it is reflected back out to space. As global warming causes more snow and ice to melt each summer, the ocean and land that were underneath the ice are exposed at the Earth’s surface. Because they are darker in color, the ocean and land absorb more incoming solar radiation, and then release the heat to the atmosphere. This causes more global warming. In this way, melting ice causes more warming and so more ice melts. This is known as a feedback. According to a recent scientific study that used computer models to predict the future of Arctic sea ice, there may be no more sea ice left in the Arctic Ocean during summer within the next few decades.

Melting Permafrost Releases Greenhouse Gas
Global warming is causing soils in the polar regions that have been frozen for as much as 40,000 years to thaw. As they thaw, carbon trapped within the soils is released into the atmosphere as methane, a powerful greenhouse gas. The methane released to the atmosphere causes more global warming, which then melts more of the frozen soils.

Less Ice on Land Means Sea Level Rises
Sea level has been rising about 1-2 millimeters each year as the Earth has become warmer. Some of the sea level rise due to melting glaciers and ice sheets which add water to the oceans that was once trapped on land. Certain glaciers and ice sheets are particularly vulnerable. Global warming has caused them to be less stable, to move faster towards the ocean, and add more ice into the water. These areas with less stable ice include the Greenland Ice Sheet and the West Antarctic Ice Sheet. If the Greenland Ice Sheet melted or moved into the ocean, global sea level would rise approximately 6.5 meters. If the West Antarctic Ice Sheet were to melt or move into the ocean, global sea level would rise approximately 8 meters.

Icebergs in the Southern Ocean Click on image for full size (21 Kb) Ute Kaden/PolarTREC

Did you know that even if you have never seen an iceberg or glacier, the snow and ice of the Earth’s cryosphere has a big impact on the climate where you live? Changes in the amounts of snow and ice on Earth have a big impact on the climate of our planet. This is because the cryosphere is a very important part of the Earth system. Scientists are currently studying just how much the frozen places on Earth affect global warming.

Below are some of the ways that the cryosphere has been affected by, and is affecting, global warming.

Melting Ice Causes More Warming
Almost all of the Sun’s rays that hit snow and ice are reflected back out to space. As more snow and ice melt because of global warming, the ocean and land that were underneath the ice are exposed at the Earth’s surface. The ocean and land absorb more of the Sun’s rays because they are dark in color. They release the heat to the atmosphere. This causes more global warming.

Melting Permafrost Releases Greenhouse Gas
Global warming is causing frozen soils in the polar regions to thaw. As they thaw, carbon trapped in the soils is released into the atmosphere as methane, a powerful greenhouse gas. The methane released to the atmosphere causes more global warming, which then melts more frozen soils.

Less Ice on Land Means Sea Level Rises
Sea level has been rising about 1-2 millimeters each year as the Earth has become warmer. Some of the rise is because melting glaciers and ice sheets are adding water to the oceans that was once trapped on land. Today, certain glaciers and ice sheets are more unstable than others. They are moving faster towards the ocean than they used to be, and are adding more ice into the water. These areas with less stable ice include the Greenland Ice Sheet and the West Antarctic Ice Sheet.