The Cryosphere
In order to take about a more complex aspect of climate change called feedback loops, I would like to begin with a discussion of Earth's ice and snow cover, called the Cryosphere. Seasonal snow covers up to 33% of Earth's surface and ice sheets and glaciers cover about 10% of Earth's surface. Additionally, between 70-75% of freshwater on Earth is in the form of icecaps and glaciers. Ice that covers a large area and grows in any direction is an ice sheet or and ice cap. Ice caps form at high altitudes, ice sheets in lower altitudes. There are two ice sheets on Earth, one located in Greenland and one in Antarctica. Ice sheets are formed by compacted snowfall over hundreds and thousands of years. Glaciers are ice that covers a much smaller geographical area, form in high altitudes, generally mountainous areas, and grow in one direction. Glaciers also form by compacted snowfall. Ice shelves are permanent floating sheets of ice connected to a landmass and are formed when ice sheets or glaciers continue to grow off the landmass and out onto the ocean. Icebergs are formed when parts of glaciers or ice sheets break off and float into the ocean.
In order to take about a more complex aspect of climate change called feedback loops, I would like to begin with a discussion of Earth's ice and snow cover, called the Cryosphere. Seasonal snow covers up to 33% of Earth's surface and ice sheets and glaciers cover about 10% of Earth's surface. Additionally, between 70-75% of freshwater on Earth is in the form of icecaps and glaciers. Ice that covers a large area and grows in any direction is an ice sheet or and ice cap. Ice caps form at high altitudes, ice sheets in lower altitudes. There are two ice sheets on Earth, one located in Greenland and one in Antarctica. Ice sheets are formed by compacted snowfall over hundreds and thousands of years. Glaciers are ice that covers a much smaller geographical area, form in high altitudes, generally mountainous areas, and grow in one direction. Glaciers also form by compacted snowfall. Ice shelves are permanent floating sheets of ice connected to a landmass and are formed when ice sheets or glaciers continue to grow off the landmass and out onto the ocean. Icebergs are formed when parts of glaciers or ice sheets break off and float into the ocean.
Ice & Climate Change
Arctic sea ice is an important indicator of climate change and it's levels are constantly monitored (as can be seen here). The ice grows and expands during the winter and melts and contracts during the summer, at it's minimum in September and it's maximum in March. While continuing to expand and contract normally, overall, however, Arctic sea ice has been dramatically decreasing. This overall loss has, among other things, contributed to sea level rise.
Source: European Space Agency
Source: European Space Agency
The resources below are fabulous places to explore more about The Cryosphere.
http://nsidc.org/cryosphere/climate-change.html
http://nsidc.org/cryosphere/quickfacts/index.html
http://www.esa.int/Our_Activities/Observing_the_Earth/CryoSat/Earth_s_changing_ice
http://www.natice.noaa.gov/Main_Products.htm
http://earthobservatory.nasa.gov/Features/WorldOfChange/sea_ice.php
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