Green House Effect and Global warming:
Natural environment and climate are dynamic and keep changing over course of time. Reasons for climate change
a) Human population growth
b) Industrialization
c) Associated anthropological activities the changes.
Impact on Global Warming:
(i) Large-scale changes of global environment can lead to hazards, which may include climate change, stratospheric ozone depletion, changes in ecosystems due to loss of biodiversity, changes in hydrological systems and the supplies of freshwater, land degradation, urbanization, and stress on food-producing systems.
(ii) Greenhouse gases (GHG) water vapour, carbon dioxide, methane, nitrous oxide, ozone and some artificial chemicals such as chlorofluorocarbons (CFCs) causes greenhouse effect. The absorbed energy warms the atmosphere and the surface of the Earth
(iii) Global warming will have a significant impact on people and nature. As global average temperatures rise, precipitation patterns could be affected. Extreme wet and dry conditions can be expected (flooding and desertification). Coastal areas shall become more vulnerable to storm surges as sea level rises. Plant and animal species will migrate or disappear in response to climate change.
(iv) Global warming can directly affect the flora and fauna. This could also result in shortage of food and even lead to a food crisis and affect the health of the people and organisms.
Control Measures:
The UNO has several measures to control or reduce pollution. Through various conventions organized by UNO, the countries assured to take steps to control or reduce emissions by factories and automobiles.

(i) CFC - Chloro fluoro carbon
(ii) AQI - National Air Quality Index
(iii) PAN - Peroxyacetyl Nitrate

Peroxyacetyl nitrate (PAN) is a secondary pollutant present in photochemical smog. It is thermally unstable and decomposes into peroxyethanol radicals and nitrogen dioxide gas causing eye irritation.

Effects: UV rays may penetrate deep into the skin and can lead to premature skin aging and wrinkling of skin; suppression of the immune system, skin cancer (melanoma) and chronic effects leading to eye damage. DNA damage can result from free radicals and reactive oxygen and photons can damage the DNA itself.

(a) Eutrophication:
1. Eutrophication is defined as the process of nutrient enrichment of water and consequent loss of species diversity in water bodies.
2. Increased nutrient content of the water body causes algal bloom, excess growth of algae, especially planktonic algae.
3. It covers the water surface, secrete toxins and reduces the dissolved oxygen content of water.
4. These toxins inhibit the growth of other algae and plants and cause death of aquatic animals.
5. O₂ deficiency may be a cause for death of animals (BOD).
(b) Algal Bloom:
1. A rapid growth of microscopic algae (or) cyanobacteria in water, often resulting in a coloured scum on the surface.
2. Rapid increase of accumulation in the population of algae in fresh water (or) marine water and is recognized by the discoloration in the water from their pigments.

Smog is a type of air pollution caused by tiny particles in the air. The word comes from a mixture of the words smoke and fog.
(i) Smog generally refers to photochemical smog, which is created when sunlight reacts with nitrogen oxides and volatile organic compounds found in fossil fuel emissions from automobiles, factories and power plants.
(ii) These reactions create ground-level ozone and particulate matter, reducing visibility.
(iii) Smog can make breathing more difficult, especially for people with asthma.
(iv) Smog also affects plants and animals. It damages crops as well as causes health problems in pets, farm animals and human beings.
(v) Smog has also been known to cause corrosive damage to buildings and vehicles.

(i) The alteration or changes in the composition of the earth's atmosphere by natural or human activities is called air pollution.
(ii) Increase in carbon dioxide concentration of air is also a form of air pollution. The normal CO₂ concentration in the atmosphere is only about 0.03%. Deforestation is one of the major contributions for increase in carbon dioxide of the air. Forests act as carbon sink by utilizing the atmospheric carbon dioxide for photosynthesis.
(iii) When forests are cut down, the concentration of the atmosphere increases. This leads to global warming or greenhouse effect which is an effect of air pollution.
(iv) Thus by forest conservation, we can reduce the carbon footprint by increased trapping of atmospheric CO₂ and thereby reducing global warming. This leads to reduced levels of air pollution.

The main goal of the Kyoto protocol is to control emissions of the main Anthropogenic (human-emitted) greenhouse gases (GHGs) in ways that reflect underlying national difference in GHG emission, wealth and capacity to make the reductions.

(i) Less use of fossil fuels.
(ii) Planting more and more trees.
(iii) Recycling of the wastes to reduce their quantity and produce useful materials.
(iv) Less or no use of fertilizers and pesticides.
(v) Dispose off the solid wastes in landfills.

1. Improvement of the purifying performance of waste water treatment plants, installing tertiary treatment systems to reduce nutrient concentration.
2. Implementation of effective filter ecosystems to remove nitrogen and phosphorus present in the run-off water.
3. Reduction of phosphorus in detergents.
4. Rationalisation of agricultural techniques through proper planning of fertilization and use of slow release fertilizers.
5. Use of alternative practices in animal husbandry to limit the production of waste water.