Greenhouse Effect and Global Warming | Science for ACT PDF Download

What is the Greenhouse Effect?

• The greenhouse effect is the mechanism responsible for Earth's elevated temperature compared to what it would be in its absence. Greenhouse gases, which trap heat, absorb energy emitted by the Earth and reflect a portion of it back towards the surface. About 26% of the solar energy received by Earth is reflected back to space by the atmosphere and clouds, with around 19% absorbed by the atmosphere.
• The remainder reaches the ground, warming the Earth's surface. This absorbed energy is then emitted as Infrared Waves, heating the atmosphere above Earth. The atmosphere subsequently re-radiates this energy received from the Earth both upwards and downwards. The downward radiation contributes to a higher equilibrium temperature than would occur without greenhouse gases. This greenhouse effect is crucial for sustaining life on Earth.

What are Greenhouse Gases?

The greenhouse gases contributing to the greenhouse effect include:

• Water Vapor
• Carbon Dioxide
• Methane
• Ozone

The excessive combustion of fossil fuels such as petrol and coal has led to an increase in greenhouse gases in the atmosphere, resulting in a phenomenon known as Global Warming. This entails a rise in Earth's ambient temperature, which could have adverse effects on life.

How do we know?

If an ideal black body were at the same distance from the Sun as Earth, its temperature would be 5.3°C. However, Earth reflects approximately 30% of this energy back into space. Accounting for this reflection, Earth's temperature would theoretically be -18°C. Yet, the actual average temperature is significantly higher at 15°C, a difference of 33°C. This disparity in ambient temperature is attributed to greenhouse gases.

Causes of Greenhouse Effect

The following are the factors that are responsible for the cause of greenhouse effect:

• Deforestation: This is considered to be one of the most responsible factors for the cause of the greenhouse effect. This is due to the reduction in the release of oxygen and absorption of carbon dioxide by the plants.
• Fossil fuel burning: Fossil fuels such as coal, oil, and natural gases are used as a means of energy which releases a huge amount of harmful gases into the environment.
• Population: As the population increases, the need for space increases which again results in deforestation.

Prevention of Greenhouse Effect

Now that we have made a list of causes, finding alternatives to these causes becomes by following the below-mentioned preventive measures:

• Afforestation: Afforestation on a large scale area helps in decreasing the release of carbon dioxide in the atmosphere.
• Conservation of energy: Switching to renewable sources of energy such as solar energy, wind energy, etc will reduce the use of fossil fuels. This eventually reduces the release of carbon dioxide into the atmosphere.
• Policy intervention: When the government comes up with strict policies to maintain the overall air quality of the city.

Greenhouse Effect and Global Warming

• Global warming refers to the increasing temperature of the Earth’s climate system and its related effects. Scientific evidence has conclusively proven that the Earth’s temperature is in fact rising and has risen by 0.85oC. This has an impact that has affected different regions differently. The effects include rising sea levels, retreating glaciers, loss of sea ice in the poles, warming global temperatures, changing precipitation, expansion of deserts, etc.
• This raises significant threats for humans such as food security from decreasing crop yields, and submergence of a low-lying area due to the rising sea. To prevent irreversible damage to the delicate ecosystems on Earth, scientists have decided that global warming should be limited to a maximum of 2.0oC relative to pre-industrial levels. The greenhouse effect plays an important role in the rising temperature. And hence to restrict global warming we need to limit the greenhouse effect and the gaseous emissions that cause the greenhouse effect.
• Fourteen of the fifteen years in the 21st century have been the hottest years on record with constant occurrences of extreme weather, cyclones, droughts, floods, etc. All these events are some way or the other have an association with the greenhouse effect and global warming.