What is Global Warming?
Slow and Gradual rise in average atmospheric temperature of earth is called Global Warming. Before the end of 19th Century (1850), the average temperature of earth was recorded 150 C.
.In the Last 150 years, the average atmospheric temperature has increased by 1.50 C, and now at the beginning of 21st Century it is 16.50 C.
This slow and steady change in the the temperature of earth in the last 150 yrs is termed as Global warming.
What are the Reasons of Global Warming?
Acc. to the 4th Assessment Report of the IPCC, this phase of Global Warming is related with wide scale human interference’s in natural habitats and ecosystems.
Human Interference’s like Deforestation, expansion of paddy cultivation, mining, excessive dependence and use of fossil fuels, growing urbanization and industrialization have increased the conc of Green House Gases in the atmosphere.
This increase in Conc. of Green House Gases has resulted in increased atmospheric Heating and resultant Global warming.
Acc to the 4th Assessment Report of the IPCC, if the current trend of global warming continues for the entire 21st century, the earth will be further warmed by 30 C to 50 C.
What are the effects of Global Warming?
Global Warming have potential to affect earth through:
1- Rise in sea Level
2- Adverse effect on ecosystems and Natural Habitat.
3- Climatic Changes
4- Decline in agricultural production and productivity
How global Warming causes Rise in Sea Level ?
Mean sea level is maintained by a balance between influx and out-flux of water in and from Oceans and Seas.
Rise in the sea level is the related with influx of water in oceans and seas exceeding Out-flux of water from Oceans.
Influx of water in oceans and seas is increasing due to melt of ice- caps and glaciers. Ice caps of polar region are shrinking and glaciers on mountains are retreating due to the effect of global warming. The water locked in these ice caps and glaciers are being released into oceans and seas. As oceans ans sea basins are receiving more water, Mean Sea level is rising and Submerging the coast.
Density of water is Max. and volume minimum at 40 C. as ocean’s ans sea temperature is rising due to global warming, there is thermal expansion of water which adds to the volume in oceans and sea basins and contribute to sea level rise.
What are the effects of Sea Level rise?
1- Ecosystems like Mangrove Forest which grow best in brackish water (mildly saline water) and inter tidal region (region between high tide and low tide) will get destroyed due to submergence caused by sea level rise.
2- As sea level rises, intrusion of saline oceanic water will rise into ground water and surface fresh water resources making water unfit for drinking, irrigation and industrial purposes.
3- Population from the coastal areas will get displaced as a result of which pressure on continental resources will increase.
4- Coral reefs will be worst affected by sea level rise which would hamper their formation and in turn aggravate the process of Coral Bleaching.
What Adverse effect on ecosystems and Natural Habitat does have Global warming?
1- Flood, Drought will enhance the process of deforestation and degradation of grasslands.
2- Incidents of Forest fires will increase. Tropical and Temperate grasslands are semi dry regions,hence are prone to forest fires during drought.
3- Global Warming will further aggravate Soil Erosion, as aridity makes soil dry which is more vulnerable to erosion.
4- Ice caps will retreat towards polar areas. As ice caps retreat and release more cold waters, oceanic circulation will get retarded/ Slow down. This will also reduce Albedo.(Reflectivity of solar radiations).
5- Perennial rivers with the melt of glaciers will become seasonal by nature. These rivers are the source of water in the valleys for drinking, irrigation and industrial purposes. Change in their pattern and flow will adversely affect economies of these river valleys.
6- Global Warming is one of the factors related with mutations in micro- organisms Harmful mutations of Viruses, bacteria and Fungi will produce new strains of diseases which will be more lethal and toxic.
How Global Warming leads to climatic Changes?
1- Magnitude and frequency of Temperate and Tropical Cyclones will Increase. This increase is associated with rise in the Temperature of Ocean Temperature. Temperate Cyclones derive their energy from Potential Energy stored in the form of moisture in hot and humid air masses (westerlies).
Strengthened atmospheric circulation due to global warming will enhance aggressiveness of hot and humid westerlies and their moisture content due to rise in moisture holding capacity of air due to increase in temperature.
2- Global warming will adversely affect shift in the pressure belts, planetary wind changes and seasonal winds. With global warming, ITCZ (Inter Tropical Convergence Zone) is shifting north, southern parts of amazon are coming under the influence of semi dry and drought prone regions.
As amazon forests are considered the lifeline of global economy, their destruction will adversely affect global ecological balance.
3- Monsoon which is a seasonal phenomena will be adversely affected by climatic changes produced by global warming. Seasonal pattern of rainfall may shift. This swing in rainfall will make monsoon unreliable and unpredictable.
How global warming leads to decreased agricultural production and productivity?
1- Increased intensity and frequency of drought, flood, temperate and tropical cyclones will affect adversely agricultural production and productivity.
2- Unpredictable climate and environmental extremes will adversely affect food production and productivity of coastal regions and river valleys.
3- Food insecurity produced by climatic change will disturb national and international peace and security. Many countries of West Asia, Central Asia and Sahara region of Africa will have more civil wars and problem of refugees generated by scarcity of food.