‘Climate change’ as a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods. The major characteristics of climate change include rise in average global temperature, ice cap melting, changes in precipitation, and increase in ocean temperature leading to sea level rise.

GLOBAL WARNING
• Unprecedented warming over the last few decades.
• -0.8°C since 1880 and still continue.
• Increase in the average global temperature of Earth’s atmosphere, near the surface and in the troposphere.

Green House (Glass House)

• Cold climate areas
• Inside temperature higher than a low outside temperature
• Protects the plants from plant

Green House Effects

• Naturally occurring phenomenon that blankets the lower atmosphere and warms it, maintaining the temperature suitable for living to survive.
• Frozen and lifeless in the absence of Green House Effects, like moon
• Venus- thick atmosphere
• Average temperature – 14°C
• In the absence of green house effect- 18°C
• Green house (Conventional) v/s Green house effect (Radiative)
Gas that absorbs and emits infrared Radiation are known as Green House Gases.

Trap Heat in Atmosphere:
– Water Vapour ( H2O)
– Carbon Dioxide (CO2)
– Methane (CH4)
– Nitrous Oxide (N2O)
– Fluorinated Gases (HFCs, PFCs, SF6, etc.)
– Nitrogen Fluoride ( NF3)

Factors that determine the degree to which any GHG will influence global warming:

– Abundance
– Ability to absorb energy (global warming potential)
– Life – how long it stays in atmosphere.

Global Warming Potential (GWP)

A measure of the total energy that a gas absorbs over a particular period of time (usually 100 years) compared to CO2.

Larger than GWP, more warming the gas causes:
(CO2-1)-Carbon Dioxide (CO2):
• Fossil fuel Burning
• Energy production – Coal and natural Gas
• Transportation- petrol and diesel industry
• Industry, production of chemicals, cements etc.

(CH4- 21)-Methane (CH4):
• Wetland
• Coal Mining
• Agriculture

– Domestic Livestock
– Rice field

• Industry
• CH4- Component of Natural Gas

(N2O- 300)-Nitrous Oxide (N2O):
• Fossil fuel combustion- In industry and transportation
• Synthetic fertilizers in Agriculture
• Livestock manual and Urine- Nitrogen complexes breakdown

(F- Gases – High GWP Gases)-Fluorinated Gases:
• HFCs to replace CFCs
• PFCs in semiconductor manufacturing
• SF6 in industrial processes
Impacts of the Climate Change:

• Climate change is expected to have a significant influence on terrestrial biodiversity at all system levels – ecosystem, species and genetic diversity.
• The changing climate will stimulate species-level changes in range and abundance, life cycle and behaviour, and, over time, genetic evolutionary responses.
• These changes will in turn be linked with changes in natural disturbance patterns and changes in ecosystem structure and function.

Impact on Agriculture

• According to World Meteorological Organization, climate change can adversely impact global environment, agricultural productivity and the quality of human life.
• More importantly in developing countries, it will be difficult for farmers to carry on farming in the increased temperatures.
• While in temperate latitudes a rise in temperature would help countries increase food productivity, it will have adverse effects in India and countries in the tropics.