Geographic Information System
(i) GIS is a computer system for capturing, storing, checking and displaying data related to positions on Earths surface
(ii) Also to manipulate, analyse, manage and present special or geographic data.
(iii) GPS is a satellite navigation system used to determine the ground position of an object.
(iv) It is a constellation of approximately 30 well spaced satellites that orbit the earth and make it possible for the people with ground receivers to pinpoint their geographic location.
(v) Some applications in which GPS is currently being used for around the world include Mining, Aviation, Surveying Agricultural and Marine ecosystems.
Importance of GIS
(i) Environmental impact assessment
(ii) Disaster management
(iii) Zoning of landslide hazard
(iv) Determination of land cover and land use
(v) Estimation of flood damage
(vi) Management of natural resources
(vii) Soil mapping
(viii) Wetland mapping.

(i) Clouds and dust particles can also produce Green House effect. That is why clouds, dusts and humid nights are warmer than clear dust free dry nights.
Green House Effect and Global Warming
(i) Green House Effect is a process by which radiant heat from the sun is captured by gases in the atmosphere that increase the temperature of the earth ultimately.
(ii) The gases that capture heat are called Green House Gases which include carbon dioxide (CO₂), methane (CH₄), Nitrous Oxide (N₂O) and a variety of manufactured chemicals like chlorofluorocarbon (CFC).
(iii) Increase in greenhouse gases lead to irreversible changes in major ecosystems and climate patterns.
(iv) For example, coral ecosystem is affected by increase in temperature, especially coral bleaching observed in Gulf of Mannar, Tamil Nadu.
(v) Human activities lead to produce the green house effect by burning fossil fuels, which releases CO₂ and CH₄
(vi) Way of Agriculture and animal husbandry practices electrical gadgets like refrigerator and air conditioners release chloro fluorocarbons.
(vii) The fertilizers used in Agriculture which release N₂O.
(viii) The emissions from automobiles. The increase in mean global temperature (highest in 4000 years) due to increased concentration of greenhouse gases is called global warming.
(ix) One of the reasons for this is overpopulation which creates growing need for food, fibre and fuel and considered to be the major cause of global warming.

Importance of GIS
(i) Environmental impact assessment
(ii) Disaster management
(iii) Zoning of landslide hazard,
(iv) Determination of land cover and land use
(v) Estimation of flood damage
(vi) Management of natural resources
(vii) Soil mapping
(viii) Wetland mapping
(ix) Irrigation management and identification of volcanic hazard
(x) Vegetation studies and mapping of threatened and endemic species.

Afforestation Objectives:
(i) To increase forest cover, planting more trees, increases O₂ production and air quality. 
(ii) Rehabilitation of degraded forests to increase carbon fixation and reducing CO₂ from atmosphere.
(iii) Raising bamboo plantations.
(iv) Mixed plantations of minor forest produce and medicinal plants.
(v) Regeneration of indigenous herbs / shrubs.
(vi) Awareness creation, monitoring and evaluation.
(vii) To increase the level and availability of water table or ground water and also to reduce nitrogen leaching in soil and nitrogen contamination of drinking water, thus making it pure not polluted with nitrogen.
(viii) Nature aided artificial regeneration.

(i) Ozone layer is a region of Earths stratosphere that absorbs most of the Suns ultraviolet radiation.
(ii) The ozone layer is also called as the ozone shield.
(iii) Ozone shield acts as a protective shield, cutting the UV rays emitted by the sun.
Bad Ozone :
(i) just above the atmosphere there are two layers namely troposphere (the lower layer) and stratosphere (the upper layer). The ozone layer of the troposphere is called as bad ozone. 
Good Ozone : 
(i) The ozone layer of stratosphere is known as good ozone because this layer acts as a shield for absorbing the UV radiations coming from the sun which is harmful for living organisms.
Ozone hole :
(i) The ozone shield is being damaged by chemicals released on the Earth's surface notably the chlorofluorocarbons widely, used in refrigeration, aerosols, chemicals used as cleaners in many industries.
(ii) This decline in the thickness of the ozone layer over restricted area is called Ozone hole.
Dobson Units:
(i) The good ozone layer acts The good ozone layer acts as a shield for absorbing the UV radiations coming from the sun which is harmful for living organisms causing DNA damage
(ii) The thickness of the ozone column of air from the ground to the top of the atmosphere is measured in terms of "Dobson Unit".

Biochar:
(i) A is another long term method to store carbon.
(ii) To increase plants ability to store more carbon, plants are partly burnt such as crop waste, waste woods to become carbon rich slow decomposing substances of material called Biochar.
(iii) It is a kind of charcoal used as a soil amendment.
(iv) It is a stable solid, rich in carbon and can endure in soil for thousands of years.
(v) Thus it has the potential to help mitigate climate change via carbon sequestration.
(vi) It increase soil fertility of acidic soils, increase agricultural productivity, and provide protection against some foliar and soil borne diseases.
(vii) It is a good method of preventing waste woods and logs getting decayed instead we can convert them into biochar thus converting them to carbon storage material.

Natural and human activities lead to produce the green house effect
(i)Green House Effect is a process by which radiant heat from the sun is captured by gases in the atmosphere 
(ii) that increase the temperature of the earth ultimately
(iii) The gases that capture heat are called Green House Gases which include carbon dioxide
(CO₂), methane (CH₄), Nitrous Oxide (N₂O) and a variety of manufactured chemicals like chlorofluorocarbon (CFC).
(iv) Increase in greenhouse gases lead to irreversible changes in major ecosystems and climate patterns.
(i) CO₂
(i) Coal-based power plants, by the burning of fossil fuels for electricity generation. 
(ii) Combustion of fuels in the engines of automobiles, commercial vehicles and airplanes contribute the most of global warming.
(iii) Agricultural practices like stubble burning result in emission of CO₂
(iv) Natural from organic matter, volcanoes, warm oceans and sediments.
(ii) Methane (CH₄):
(i) It is 20 times as effective as CO₂ at trapping heat in the atmosphere.
(ii) Its sources are attributed paddy cultivation, cattle rearing, bacteria in water bodies, fossil fuel production, ocean, non-wetland soils and forest wild fires.
(iii) N₂O:
(i) It is naturally produced in Oceans from biological sources of the soil and water due to microbial actions and rainforests.
(ii) Man-made sources include nylon and nitric acid production, use of fertilizers in agriculture, manures cars with catalytic converter and burning of organics.

Green house effect:
Green house effect is a process by which radiant heat from the sun is captured by a gases in the atmosphere that increase the temperature of the earth ultimately, the gases that capture heat are called "Green house gases 
E.g.CO₂, CH₄, N₂O and CFC.
Coral bleaching:
(i) Increase in green house gases lead to irreversible changes in major ecosystems and climate patterns.
E.g. The coral ecosystem is affected by increase in temperature, especially "coral bleaching" observed in Gulf of Mannar, Tamil Nadu.
Human activities lead to produce the green house effect.
(i) Burning fossil fuels, which releases CO₂ and CH₄ Way of Agriculture and animal husbandry practices
(ii) Electrical gadgets like refrigerator and air conditioners release chloro fluorocarbons.
(iii) The fertilizers used in Agriculture which release N₂O.
(iv) The emissions from automobiles
Global warming:
(i) The increase in mean global temperature (highest in 4000 years) due to increased concentration of green house gases is called global warming.
Effects of global warming:
(i) Rise in global temperature which causes sea levels to rise as polar ice caps and glaciers begin to melt causing submergence of many coastal cities in many parts of the world.
(ii) A drastic change in weather patterns bringing more floods or droughts in some areas.
(iii) Biological diversity may get modified, some species ranges get modified.
(iv) Tropics and sub-tropics may face the problem of decreased food Production.

Every human activity leaves a mark just like our footprint. This Carbon footprint is the total amount of greenhouse gases produced by human activities such as agriculture, industries, deforestation, waste disposal, burning fossil fuels directly or indirectly. It can be measured for an individual, family, organization like industries, state level or national level. It is usually estimated and expressed in equivalent tons of CO₂ per year. The burning of fossil fuels releases CO₂ and other greenhouse gases. In turn, these emissions trap solar energy and thus increase the global temperature resulting in ice melting, submerging of low lying areas and imbalance in nature Iike cyclones, tsunamis, and extreme weather conditions. To reduce the carbon footprint we can follow some practices like
(i) Eating indigenous fruits and products
(ii) Reduce use of your electronic devices
(iii) Reduce traveling
(iv) Do not buy fast and preserved, processed, packed foods.
(v) Plant a garden
(vi) Less consumption of meat and seafood. Poultry requires little space, nutrients and less pollution comparing cattle farming.
(vii) reduce the use of Laptops (when used for 8 hours, it releases nearly 2 kg. of CO₂ annually)
(viii) Line dry your clothes. (Example: If you buy imported fruit like kiwi, indirectly it increases CFP. How? The fruit has traveled a long distance in shipping or airliner thus emitting tons of CO₂)

Eichhornia crassipes is an invasive weed native to South America. It was introduced as aquatic ornamental plant, which grows faster throughout the year. Its widespread growth is a major cause of biodiversity loss worldwide. It affects the growth of phytoplankton and finally changing the aquatic ecosystem.
It also decreases the oxygen content of the waterbodies which leads to eutrophication. It poses a threat to human health because it creates a breeding habitat for disease-causing mosquitoes (particularly Anopheles) and snails with its free-floating dense roots and semi submerged leaves. It also blocks sunlight entering deep and the water ways hampering agriculture, fisheries, recreation, and hydropower.

Afforestation Objectives:
(i) To increase forest cover, planting more trees, increases CO₂ production and air quality.
(ii) Rehabilitation of degraded forests to increase carbon fixation and reducing CO₂ from atmosphere.
(iii) Raising bamboo plantations.
(iv) Mixed plantations of minor forest produce and medicinal plants.
(v) Regeneration of indigenous herbs/shrubs.
(vi) Awareness creation, monitoring, and evaluation.
(vii) To increase the level and availability of water table or ground water and also to reduce nitrogen leaching in soil and nitrogen contamination of drinking water, thus making it pure not polluted with nitrogen.
(viii) Nature aided artificial regeneration.

The main ozone depletion effects are:
(i) Increases the incidence of cataract, throat and lung irritation and aggravation of asthma or emphysema, skin cancer and diminishing the functioning of the immune system in human beings.
(ii) Juvenile mortality of animals.
(iii) Increased incidence of mutations.
(iv) In plants, photosynthetic chemicals will be affected and therefore photosynthesis will be inhibited. Decreased photosynthesis will result in increased atmospheric CO2 resulting in global warming and also a shortage of food leading to a food crisis.
(v) Increase in temperature changes the climate and rainfall pattern which may result in flood/drought, sea water rise, imbalance in ecosystems affecting flora and fauna.