[Solved] How does the cryosphere affect global climate? ( UPSC GS-1 Mains 2017)
Cryosphere is an integral part of the global climate system with important linkages and feedbacks generated through its influence on surface energy and moisture fluxes, clouds, precipitation, hydrology, atmospheric and oceanic circulation. It plays a significant role in the global climate and in climate model response to global changes through these feedback processes.
The frozen water is present in different forms (snow, sea ice, lake and river ice, glaciers, ice sheets, icebergs and frozen ground) altogether within the climate system is called as the ‘Cryosphere’.
Hence, we can say that there is coincide partially or wholly with the hydrosphere. It is an integral part of the global climate system with important linkages and feedbacks generated through its influence on surface energy and moisture fluxes, clouds, precipitation, hydrology, atmospheric and oceanic circulation.
It plays a significant role in the global climate and in climate model response to global changes through these feedback processes.
Before, moving on to the discussion, firstly know that- What is Albedo? Albedo is the measurement of reflectivity of an object.
In other words, it is the measure of the diffuse reflection of solar radiation out of the total solar radiation received by an astronomical body. According to the definition, we can say that every object has a different albedo.
How does the cryosphere affect global climate?
- The state of the cryosphere strongly depends on and interacts with atmospheric conditions, on local to hemispheric spatial scales, and on hourly to glacial-interglacial scales.
- It has a non-linear response to changes in temperature, due to threshold effects associated with melt.
- The affects of Cryosphere on global climate are discussed below: 1. The Albedo of snow/ice sheet is high and plays important role in solar radiation because reflect much of the insolation, which helps in cooling of the earth.
- But due to global warming, some of the snow/ice-sheets are getting melt which resulted multiplier effects.
- Thus, presence or absence of snow and ice affects the heating and cooling of Earth’s surface. This influences the entire planet’s energy balance.
- It influences the surface energy, greenhouse gases and water fluxes. For Example- Changes in Arctic sea ice and snow cover may affect the mid-latitude atmospheric circulation.
- It plays important role in cooling the air which affects the climate of the regions of Iceland, Greenland, Russia etc.
Geological Time Scale
- The polar region acts as carbon sink and trapped tonnes of carbon inside its soil. If the frozen water form like snow, sea ice, lake and river ice, glaciers, ice sheets, icebergs and frozen ground melts then it will release in form of methane- a powerful greenhouse gas- which will catalyse the global warming.
- When seawater is condense into sea ice at Polar region then the surrounding water gets saltier. Saltier water has higher density; it sinks and initiates thermohaline circulation patterns across the oceans of the world. These Ocean currents act like a conveyer belt, transporting warm water from the equator toward the poles and cold water from the poles back to the tropics. Thus, currents regulate global climate. Some of these currents affect rain and drought situation via El-Nino La-Nina effect.
- If the frozen form of water melts, then the volume of water in the oceans will be affected. So any changes in the water cycle, affects global energy / heat budget, and thereby global climate.
- The Intergovernmental Panel on Climate Change (IPCC) in their 5th Assessment Report states that there has been a continued net loss of ice from the cryosphere, although there are significant differences in the rate of loss between Cryosphere components and regions.
- Hence, we can say that Cryosphere has direct and indirect bearing on the global climate. Therefore, if we want to protect the biosphere then we must protect the Cryosphere.
- There are places on Earth that are so cold that water is 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.
Impact on global climate:
- Cryosphere is the region of highest albedo over the earth system. Thus, it helps regulating the overall heat budget of the earth.
- Due to differences in the temperature of the cryosphere and the tropical regions, the atmospheric phenomenon such as planetary winds, ocean currents etc. occur.
- Cryosphere is the significant place for carbon sequestration as huge amount of carbon is trapped within these soils in the form of methane.
- Decrease in cryosphere due to global warming may lead to increase in sea level which will further lead to change in climatic pattern.
- 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.
- Thus, citing sea ice melt, UNEP has urged stronger measures to protect fragile cryosphere environment Effects of Cryosphere on global climate
Maintaining global temperatures
The biggest role played by Cryosphere is maintaining global temperatures by acting as reflecting surfaces. The snow has high albedo due to which majority of sun rays will be reflected and heat will be reduced. This is very essential for reducing global warming.
Carbon trapping agents
Cryospheric regions have large amounts of active carbon dioxide trapped below their surface due to frozen nature. This has prevented the carbon to escape and contribute towards global warming phenomenon.
The cryospheric regions are major source of rivers and streams that are essential parts of water cycle. The dispersed water in form of rivers is cycled back in form of rainfall and snow to keep the global balance intact.
The unburnt carbon settles on top of snow surface and act as absorbents of heat. This will result in melting of ice and subsequent events such as sea level rise and carbon release.
The region of Cryosphere, eventhough do not contribute much to human habitat, have a large role in maintaining the climate of the world. Saving these regions must be a top priority.
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