Sample Lecturette 11: Global Warming | Preparation Tips for SSB Interview - CDS PDF Download

What is Global Warming?

Greenhouse Effect and Global Warming

• To understand the greenhouse effect, let's first consider what a greenhouse is.
• A greenhouse is a glass structure used to grow plants in winter.
• The glass panels of a greenhouse allow light to enter but prevent heat from escaping, creating a favourable environment for plant growth.

Clouds and gases in the atmosphere reflect a quarter of the sun's radiation and absorb a small portion of it. Over fifty percent of the sun's radiation reaches the Earth's surface. The surface then emits heat, but some of it gets trapped by greenhouse gases like carbon dioxide, methane, and sulfur dioxide. These gases radiate heat, which returns to the Earth's surface, causing the temperature to rise. This cycle repeats, leading to an increase in the Earth's temperature. In the last century, the Earth's temperature has risen by approximately 0.6℃.

Causes of Global Warming

• Volcanoes: When volcanoes erupt, they release smoke and ash into the atmosphere, negatively impacting the climate. This is a well-known natural factor contributing to Global Warming.
• Water Vapour: Water vapour is a type of greenhouse gas. As the Earth's temperature rises, water evaporates from bodies of water and accumulates in the atmosphere, causing harmful effects on the environment.
• Melting Permafrost: Permafrost refers to frozen soil that contains trapped environmental gases from many years. It is found beneath the Earth's surface, including in glaciers. When permafrost melts, it releases gases into the atmosphere, leading to an increase in the Earth's temperature.
• Forest Fires: Forest fires result in the emission of large quantities of smoke containing carbon components. These gases enter the atmosphere, contributing to the rise in Earth's temperature.

Global Warming Projects

• Chlorofluorocarbons (CFCs): The widespread use of refrigerators and air conditioners releases significant amounts of CFCs into the environment, which harm the ozone layer. The ozone layer's role is to block harmful ultraviolet rays from reaching the Earth's surface. CFCs deplete the ozone layer and consequently raise the Earth's temperature.
• Deforestation: Trees and plants are crucial sources of oxygen. They absorb carbon dioxide and release oxygen, helping to maintain environmental balance. Due to commercial and domestic activities, forests are being excessively depleted, leading to environmental imbalances and Global Warming.
• Excessive Use of Vehicles: Emissions from vehicles pose a threat to the atmosphere. Since vehicles run on fossil fuels, they emit carbon dioxide and other toxins into the environment, contributing to a rise in the Earth's temperature.
• Agriculture: Various agricultural activities release gases such as methane and carbon dioxide. The release of these greenhouse gases into the environment contributes to an increase in the Earth's temperature.
• Industrial Development: The establishment of industries has a significant impact on the environment. Smoke and emissions of harmful gases from factories contribute to the rising temperature of the Earth.

Global Warming and Its Effects

Global warming has a significant impact on coral reefs, leading to the loss of animal and plant life. The rising temperatures of the Earth are making coral reefs more vulnerable.
Global warming is responsible for various changes in the climate. It creates imbalances such as floods in some areas and droughts in others, which are direct consequences of global warming.
The heat and humidity patterns also fluctuate due to global warming, resulting in the movement of mosquitoes and the spread of diseases. Global warming leads to a higher mortality rate due to increased natural disasters like earthquakes, floods, and tsunamis.
Global warming is affecting people's lives in various ways. As the Earth's temperature rises, animals are forced to migrate from their natural habitats to survive. Unfortunately, many animals become extinct during this process.
The issue of global warming has been discussed by numerous international organizations, but only a few have been able to take effective action. This is because the issue primarily concerns a small educated segment of the population who are aware of its environmental impacts. However, by raising awareness and implementing small-scale campaigns, we can take significant steps towards preventing global warming.