Global environmental change and its effect on India's climate

How extra greenhouse gases warm the Earth

1. 1
   Sunlight reaches the Earth. About 51 percent of the Sun's energy is absorbed by the Earth's surface, which warms up.
2. 2
   The warm surface sends heat back out towards space.
3. 3
   Greenhouse gases, mainly carbon dioxide, trap part of this outgoing heat.
4. 4
   A natural amount of these gases keeps the Earth warm enough for life.
5. 5
   Human activities add more of these gases, so more heat is trapped.
6. 6★
   So the Earth's average temperature rises. This is global warming.

★ key step

Human activities behind it

• Burning fossil fuels (coal, petrol, diesel and gas) in vehicles, power plants and factories releases carbon dioxide.
• Cutting forests removes trees that take in carbon dioxide.
• Fast industrialisation and urbanisation (growth of cities) increase the use of energy.
• Population growth raises the demand for energy and goods.
• CFCs from old refrigerators, air conditioners and spray cans harm the atmosphere.

Effects on India's climate and life

• The cycle of seasons is disturbed, and the monsoon becomes less regular.
• Rain may come in heavy bursts with long dry gaps, raising the risk of floods and droughts.
• Warmer temperatures can melt Himalayan glaciers, which feed the perennial rivers.
• A rising sea level threatens low coasts and deltas.
• Farming, on which a large share of Indians depend, is hurt by any change in temperature and rain.
• Health and transport are also affected, so the change has serious social and economic effects.

What each of us can do

• Use public transport, share rides, cycle or walk for short trips.
• Save electricity: switch off lights and fans, and use efficient bulbs.
• Plant and protect trees.
• Reduce, reuse and recycle, and do not burn garbage.
• Support clean energy such as solar power, and avoid CFC-based appliances.