Question

Speech on climatic change due to greenhouse effect or global warming

Answer 1

Greenhouse gases warm the atmosphere by absorbing some of the thermal radiation emitted from the Earth's surface. Incoming solar radiation is transmitted through the atmosphere to the Earth's surface. The energy is retransmitted by the Earth's surface as thermal radiation. Some of the thermal radiation is absorbed by the greenhouse gases instead of being retransmitted out to space, and so there is a warming of the atmosphere. The important greenhouse gases which are directly influenced by human activities are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), chlorofluorocarbons (CFCs) and ozone. Water vapour is also an important greenhouse gas.