The increasing use of fossil fuels and deforestation have led to an increase in the levels of CO₂ in the air. Gases like water vapour, methane, and carbon dioxide act in a similar way in the atmosphere. These gases are called greenhouse gases.
When sunlight reaches the Earth's surface, some of it is absorbed by the Earth's surface, including vegetation, oceans, and land. This absorption warms the earth. As the earth's surface heats up, it emits energy in the form of infrared radiation. Greenhouse gases absorb this energy. These gases re-radiate some of the infrared radiation.
DO YOU KNOW? Greenhouses are constructed from glass or transparent polymer films. Sunlight can pass through these materials and is used by the plants for photosynthesis. The plants radiate some energy in the form of infrared or heat radiations which cannot pass through these materials and is reflected back. As a result, the atmosphere inside the greenhouse becomes hot enough to promote plant growth. The temperature inside a greenhouse can be 10°C to 15°C higher than outside.
As a result, greenhouse gases act like a blanket, trapping some of the heat energy in the lower atmosphere. This process is referred to as the greenhouse effect. This effect reduces thermal energy loss to space and helps to regulate the Earth's temperature. Without this effect, the Earth would be much colder, making it difficult for life to exist. Human activities have been increasing the concentration of greenhouse gases in the atmosphere, by burning fossil fuels, deforestation, and industrial processes. This additional increase in greenhouse gases is enhancing the natural greenhouse effect. This is significant, leading to an increase in the atmospheric temperature causing global warming and climate change. The higher the concentration of greenhouse gases in the air, the greater the greenhouse effect and the greater the increase in temperature. The greenhouse effect is a natural phenomenon of the earth's energy distribution mechanism. The warming of the atmosphere due to our influence on the greenhouse effect is called global warming. Global warming is caused by disturbing the natural balance of greenhouse gas concentrations in the atmosphere.
If global warming continues, then:
1. Define global warming.
2. List some effects of global warming.
3. List some substances that are responsible for global warming.
4. Establish the link between greenhouse effect and global warming.
Incineration is a waste treatment process in which solid waste is burned at high temperature. Incineration consumes all combustible materials, leaving behind ash residue and non-combustible material. This process generally reduces the volume of waste by two-thirds, but it is not a clean process. It produces air pollution. It generates considerable smoke and odour. This smoke may contain oxides of nitrogen and sulphur.