Human Activity and Climate Change

Scientists all around the world are discovering more evidence that the Earth’s climate is changing because of the increase in greenhouse gases. Some of the key findings include:

  • A significant rise in the concentration of carbon dioxide (CO2) in the atmosphere
  • An increase in the average global temperature, also known as global warming.

Let’s look at how the increase in carbon dioxide is causing global warming.

Greenhouse effect

The increase in carbon dioxide in our atmosphere contributes to global warming due to something known as the greenhouse effect. This is when certain gases in the Earth’s atmosphere trap heat from the sun, which warms the planet’s surface.

1. The Earth’s warmth is necessary for sustaining life and this warmth comes from the Sun’s solar radiation. As shown in the diagram, the Earth absorbs this radiation, which heats it up.

  • Imagine a blanket that keeps us warm; the Earth’s atmosphere works the same way. It helps keep the warmth inside so that life can survive.

2. This warming causes the Earth to radiate back infrared heat waves.

3. There are various greenhouse gases in the atmosphere, such as carbon dioxide and methane. These gases absorb the reflected infrared waves and prevent them from exiting the Earth’s atmosphere. This leads to further warming of the atmosphere.

4. The greenhouse gases re-radiate the infrared waves back towards Earth, leading to a warming effect known as global warming.

  • As the concentration of greenhouse gases in the atmosphere increases, more infrared waves are absorbed and reflected back to Earth. This leads to an amplified warming effect.

Causes of Climate Change

The causes of climate change are all linked to the emissions of greenhouse gases.

Burning fuels

Burning fossil fuels is a major cause of climate change. This can include burning fuels in vehicles, factories and power plants. When these fuels are burned, they release large amounts of carbon dioxide and other greenhouse gases into the atmosphere, which trap heat and cause global warming.

The carbon that was once safely stored in these fossil fuels is now released into the air as carbon dioxide. This contributes to the greenhouse effect and climate change.

Farming Cattle

Cattle farming is a major source of methane (CH4) emissions, which is a powerful greenhouse gas. Methane has a warming effect on the planet that is about 28 times stronger than carbon dioxide over a 100-year time frame.

The release of methane into the atmosphere from cattle farming operations contributes to global warming and climate change.


To get suitable land for farming, we often have to cut down trees and vegetation. Trees absorb carbon dioxide from the atmosphere for photosynthesis. Cutting down trees prevents this process from taking place, so the concentration of carbon dioxide in the atmosphere increases.

  • Remember, cutting down trees does not release carbon dioxide; it only reduces the amount of carbon that is absorbed through photosynthesis.

A Consequence of Global Warming

Melting ice caps and rising sea levels

Global warming has a significant impact on the habitats of animals and plants, as it leads to changes in climate patterns and temperature.

As temperatures rise, polar ice sheets and glaciers are melting faster than they can form. At the same time, water expands when heated. The combination of these two factors, among others, leads to rising sea levels.

Rising sea levels caused by global warming can lead to flooding and erosion of coastal areas. This can damage buildings and infrastructure, causing many people to become homeless.

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