Environmental Issues

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Deforestation

40% lost in the Tropics. 1% in Temperate

National forest policy 1988 recommend 33% for Plains and 67% for Hills

Currently 30% reduced to 19.4%

Slash and Burn cultivation: By North-eastern people. Ash- fertilizer Land- Farming/grazing. Increasing population decreases recovery phase leading to deforestation

Consequences:

Enhances Co2 conc

Loss of biodiversity due to Habitat destruction

Disturbs hydrologic cycle

Soil erosion

desertification (extreme case)

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Soil Erosion:

Over cultivation

Over grazing

Deforestation

Poor irrigation

Desertification major problem due to Urbanization

Water logging:

Irrigation without proper drainage

Draws salts to the surface- forms thin crusts on the land- collects on the Roots- effects growth and agriculture

Arised after Green revolution

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Ozone Depletion

DNA and proteins absorbs UV light whose high energy breaks chemical bonds within

Thickness of ozone measured in unit of Dobson unit

UV rays act on CFCs releasing Cl atoms which degrades ozone

Cl atoms act as Catalyst: CFCs have permanent and continuing effect

Mainly in Antarctic region during late August to early October

Effects of UV-B:

Damages DNA, Skin cells

Causes Mutation

Aging of skin, skin cancer

High dose causes Inflammation of cornea: Snow blindness

Cataract, permanent damage to Cornea

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Greenhouse Effect:

Average temp at earths surface is 15 celsius. Without greenhouse effect it will be -18 celsius

1/4th of sunlight reflected by clouds and gases. 1/2 of it heats the surface. Small amount reflected back

Earth re emits it as Infrared and get absorbed by Green house gases

Composition: Co2- 60%, Methane- 20%, CFCs- 14%, N2O- 6%

Effects:

Last 3 decades temp raised by 0.6 celisus

El Nino effect

Melting of polar ice caps (Himalayan snowcaps)

Rise in sea level

Solutions:

Cutting down fossil fuels

Reducing deforestation

Improving efficiency of energy usage

Slowing down growth of human population

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Radioactive Wastes:

Problems of using nuclear energy: 1. Accidental leakage 2. Safe disposal

at very high rate causes mutations and is lethal

At low rate causes disorders like cancers

Extremely potent pollutant

After pre-treatment they should be stored in shielded containers and buried within rocks 500m deep

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Solid wastes: