State the sources and effects of the following gases :
(i) Carbon dioxide
(ii) Methane
(iii) Water vapour
i). Carbondioxide:
Carbon dioxide occurs naturally in the atmosphere. It is an essential ingredient in photosynthesis, the process by which plants make food and energy.
Levels of atmospheric carbon dioxide have increased since the Industrial Revolution. The primary causes are deforestation and the burning of fossil fuels such as coal. As carbon dioxide levels have risen, so have its effects on air pollution.
Carbon dioxide contributes to air pollution in its role in the greenhouse effect.
Certain gases in the atmosphere block heat from escaping. Long-lived gases that remain semi-permanently in the atmosphere and do not respond physically or chemically to changes in temperature are described as "forcing" climate change. Gases, such as water vapor, which respond physically or chemically to changes in temperature are seen as "feedbacks."
Gases that contribute to the greenhouse effect include:
ii). Methane
There are both natural and human sources of methane emissions. The main natural sources include wetlands, termites and the oceans. Natural sources create 36% of methane emissions.
Human-related sources create the majority of methane emissions, accounting for 64% of the total.
The methane gas which causes sever global warming in the atmosphere.
iii). Water vapor.
Water vapor, water vapour, also aqueous vapor, is the gas phase of water. Water vapour is the most important greenhouse gas. This is part of the difficulty with the public and the media in understanding that 95% of greenhouse gases are water vapour.
The most abundant greenhouse gas, but importantly, it acts as a feedback to the climate. Water vapor increases as the Earth's atmosphere warms, but so does the possibility of clouds and precipitation, making these some of the most important feedback mechanisms to the greenhouse effect.