Global environmental issues
Transcript of Global environmental issues
55% contributor to Global Warming & 500 yrs life span
18% contributor to Global Warming(GW) and 7-10 yrs life span
6% contributor and 140-190 yrs life span
1000 yrs life span
CFC’S24% Contributor &
life span of 110 yrs
GLOBAL WARMINGPresences of GHE, avg. global
temperature is 15°C.In absences of them it would be
-18°C.Therefore GHE, contributes
33°C temperature rise.Two Important GHG’s are
Water Vapour & CO2.BCoz of excess GHG’s, scientist
worry about incraese in avg temp. more than 15°C.
Causes due to Deforestration, Anthropogenic activities like fossil fuel burning.
This leads to Sea Level Rise.
SEA LEVEL RISE
In the last century 15-20 cm rise in se level has been witnessed.
IPCC projected rise in between 18 and 59cms.
Reasons:1)Thermal Expansion2)Melting
of IceEnd of 21st Century, rise is
expected to be between 0.56 and 2m.
Melting of Greenlands & West Antarctica – 6m rise.
Causes:Flooding of Coastal
areas like Bangladesh, Mumbai, Lakshadweep
Disturb Spawning grounds.
Disturb Coastal Fisheries.
Flooding agriculture lands & low land.
Increases Soil Erosion
Increases Salinity of aquifers & Estuaries.
Inundate large areas of Wetlands.
CLIMATE CHANGE1. Climate is the average weather of an area.
2. The Intergovernmental panel of Climate Change (IPCC) – 1990 & 1992 published the best available evidence about past climate change, GHE and Global Warming during the geological times.
3. Anthropogenic activities – Upset Hydrological Cycle, Results in flood and Drought, causes sea level rise, changes in agriculture productivity, famines, death of humans & livestock.
4. The global changes in temperature will not be uniform everywhere and will fluctuate in different regions.
5. Poles experience 2 to 3 times more warming than the global average, while warming in the tropics may be only 50 to 100% on an average.
Earth’s Temperature will rise in between 1.5°C to 5.5°C by 2050.
Impact on Human Environment
1. Global Temperature Increase:
2. Rise in Sea Level:Expanding of water due to increase in temperature.
• Melting of Polar Ice Caps.
• Increase in Global Sea Level by 0.2-1.5 metres over the next 50-100 years.
• One meter rise will inundate Sydney, Bangkok, Cairo etc, Agricultural Lands of Bangladesh, India, China will effect rice production.
• Lives of many people living near these cities.
3. Effects on Human Health:Spread of Diseases like Filariasis, Elephantiasis, Malaria etc.As the Vectors spreading these diseases will be increase in no. due to stagnation of water and high temperature to survive(Mosquitoes, Snails Etc).Increase in Respiratory and Skin Diseases due to high temp. & Humidity.
4. Effect on Agriculture:• Soil Moisture will
decrease & evapo-transpiration will increase – affecting wheat and maize production.
• Increase in pest no. due to high temp. & Humidity.
• To cope up this pest, heat and drought resistant varieties to be developed.
Atmospheric Ozone measured using Dobson Spectrophotometer and expressed in Dobson Units(DU).Temperate Latitudes = 350 DUTropics = 250 DUSub- Polars = 450 DUOzone Hole:An undeniable problem in AntarcticaResearcher Joseph Farman had been collecting atmospheric data at Halley Bay, Antarctica since 1957. Every year he sent a team of research assistants to measure ozone levels and concentrations of trace gases like CFCs. In 1982, his ozone reading showed a dramatic dip — around 40%. Rather than being alarmed, he was skeptical of the data and thought it must be an instrument malfunction.
OZONE DEPLETING SUBSTANCES1. CFC’s2. Halon3. Carbon Tetrachloride(CCl4), Methyl Chloroform(CH3CCl3)4. Hydrobromofluorocarbons (HBFC’s)5. Hydrochlorofluorocarbons(HCFC’s)6. Methyl Bromide(CH3Br)7. Bromochloromethane(CH2BrCl)
Effects of Ozone Depletion1. Mutation in the DNA – Hereditary Problems.2. Skin Cancer.3. UV absorbed by lens and Cornea – Cataract.4. Melanin in skin destroyed by the UV.5. Decrease in Phytoplankton Population – Later impacting the ecosystem.6. Yield of crops like corn, rice, soyabean, cotton etc are decreased.7. Degradation of Paints, Plastics and other polymer material will result in economic loss due to UV rays.
Facts:Forest Cover in Total World in 1900 was 7000
Million Hectares, but in 1975 – 2980 Million Hectares and in 2000 – 2300 Million Hectares.
Due to global efforts in 2010 it increased to 4033 Million Hectares.
In next 60 years about 90% of the tropical forests will be destroyed.
India’s Forest cover is 21.02%.(2009 Forest Report)
Major Causes of DeforestationShifting CultivationFuel RequirementRaw Material for Industrial UseDevelopmental Projects.Growing Food Needs.Over GrazingForest Fires.
ConsequencesExtinction of Species due to
habitat loss.Hydrological Cycle effected
thereby effecting rainfall.Soil Erosion and loss of soil
fertility.Landslides in hilly areas.Moe Carbon is added into the
atmosphere, thereby enhancing Global Warming.
Productive Potential of Arid & Semi-Arid lands falls by 10% or more.Moderate Desertification – 10-25% drop in productivity.Severe – 25 – 50%Very Severe – more than 50%
Consequences:Loss of VegetationGround water depletionSalinization and severe soil erosion
Causes of Desertification
Natural Phenomena – Climate Change Anthropogenic Factors1. Deforestation2. Over Grazing3. Mining and Quarrying.