Defination of Cryosphere: When we talk about the cryosphere, it means the places where water is in its solid form, frozen into ice or snow.
Mostly people think Earth’s frozen regions as being at the top and bottom of our planet, in the polar regions. As We call the area around the North Pole the Arctic and the area around the South Pole the Antarctic. But snow, ice and frozen ground are also found at many other locations on Earth.
True Words for cryosphere :In the earth, the place where the water is available in the solid state is called cryosphere.
There are some places on Earth that are so cold that water is present there as frozen solid. These areas of snow or ice, which are subject to temperatures below 32°Ffor at least part of the year, compose the cryosphere. The term “cryosphere” comes from the Greek word, “krios,” which means cold. Read More
Ice and snow on land are one part of the cryosphere. This includes the largest parts of the cryosphere, the continental ice sheets found in Greenland and Antarctica, as well as ice caps, glaciers, and areas of snow and permafrost. When continental ice flows out from land and to the sea surface, we get shelf ice.
The other part of the cryosphere is ice that is found in water. This includes frozen parts of the ocean, such as waters surrounding Antarctica and the Arctic. It also includes frozen rivers and lakes, which mainly occur in polar areas.
The components of the cryosphere play an important role in the Earth’s climate. Snow and ice reflect heat from the sun, helping to regulate our planet’s temperature. Because polar regions are some of the most sensitive to climate shifts, the cryosphere may be one of the first places where scientists are able to identify global changes in climate.
How cryosphere affect global climate
- Since the Albedo of snow/ice is high, the significant part of the solar radiation is reflected back resulting in the lower temperature of earth. But, due to increase of global average temperature, some of the snow gets melted which results in a multiplier effect. For example, there is 100 tonne of snow and it was receiving 100 KJ and reflecting back 80 KJ of solar energy. Due to some reason, 20 tonnes of snow melted. Now remaining 80 tonnes of snow will receive 100 KJ but reflect less than 80 KJ say 60 KJ. There will be net gain of energy thus it will again melt the ice and the cycle goes on.
- The cryosphere has a role in cooling the air thus affecting the climate of regions of Iceland, Greenland, Russia etc.
- Ocean current like Labrador current brings meltwater from glaciers to the Eastern coast of Canada and USA. Cold freshwater is favorable for fishing grounds. Also, people get some relief from summer.
Cryosphere can lead to the initiation of feedback effect that begins by increases in the albedo, an increased reflectivity, an increase in outgoing earth radiation, cooling of the Earth-atmosphere system, expansion of ice cover leading to renewed albedo induced cooling.
Cryosphere locks the greatest amount of CO2 in the world and any changes in the temperature have an effect in further locking or even releasing CO2 back in the atmosphere consequent upon its melting.
Impacts of Melting Cryosphere
Research has found that the environmental changes at both poles cannot result from natural climate change alone, and is directly attributable to man-made climate change.
This has knock-on effects. The cryosphere is an important part of our water cycle. Ice locks water out of the cycle for long periods of time – with large-scale melting, a vast amount of water can be released back into the water cycle in a relatively short amount of time.
Unsurprisingly, water from the current cryosphere melt is contributing to the global sea level rise. the observed increase in global sea level is currently at the upper limit of projections made by the IPCC in 1990.
As ice loss from both the polar ice sheets and mountain glaciers accelerates, the global sea level rise is also set to increase. One recent study suggests that the Greenland and Antarctic ice sheets are likely to be the dominant contributor to sea level rise in the 21st century, providing around half of all sea level rise over the next 40 years. Ice melt from glaciers is also likely to play an important role.
Given current melting rates, and taking thermal heat expansion of the oceans into account, total sea level rise is estimated to be around 32 cm by 2050.
Melting ice also has implications for water supply, with many millions of people around the globe dependent on rivers fed by mountain glaciers. For example, in the Indus and Brahmaputra basins alone around 60 million people rely on glacial meltwater for their water supply.
With glaciers melting faster, the IPCC has suggested that in the short term summer river flow is likely to increase – but further into the future river flow is likely to decrease as the ice feeding rivers disappear.
What is Permafrost
A ground, frozen for at least two years Which Contains large amounts of carbon, stored as frozen methane or organic material unable to decay in its frozen state. this thick layer of soil is called Permafrost
Researchers from the National Snow and Ice Data Center (NSIDC) estimate that if permafrost melt continues, around 190 gigatonnes of carbon could be released into the atmosphere by 2200, further warming the planet. To put this figure in context, in the year 2010 manmade greenhouse gas emissions were at around 30 gigatonnes.
Scientists are also warning of a more immediate potential threat from melting permafrost, suggesting that methane released from seafloor permafrost in the Arctic Ocean could enhance ocean acidification in that region over the next century.