Human Activity and Climate Change

There are various studies that show a change in climate as a result of increasing greenhouse gases. This includes:

  • A rise in carbon dioxide (CO2) concentration of the atmosphere
  • An increase in the mean global temperature (global warming)

Let’s look at how carbon dioxide causes global warming.

Greenhouse effect

Carbon dioxide leads to global warming due to an effect called the greenhouse effect.

1. In order to sustain life on our planet, the planet has to be relatively warm. We can get this warmth from the Sun’s solar radiation. As you can see in the diagram above, the Earth absorbs this incoming solar radiation from the Sun, which heats it up.

2. As a result, the Earth reflects back infrared heat waves.

3. There are various greenhouse gases in the atmosphere, such as carbon dioxide and methane. These greenhouse gases absorb the reflected infrared waves and prevent them from exiting the Earth’s atmosphere, to get into space. This heats the atmosphere.

4. The greenhouse gases reflect the infrared waves back towards Earth, leading to a warming effect.

Some of the infrared waves are able to escape the Earth’s atmosphere. However, the higher the concentration of greenhouse gases present in the atmosphere, the more infrared waves are being absorbed and reflected back towards Earth, which heats up our planet and causes global warming.

Causes of Climate Change

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

Burning fuels

Burning fuels is a major cause of climate change. This can include burning fuels in vehicles, factories and power plants. The carbon that was once stored in fossil fuels (in a harmless state) is now dug up and released into the atmosphere in the form of carbon dioxide (CO2).

Farming Cattle

Cattle farming releases a lot of methane (CH4) into the atmosphere, which is a greenhouse gas, therefore it is a big issue.


To get suitable land for farming, we often have to cut down trees and vegetation. Trees absorb carbon dioxide (CO2) from the atmosphere for photosynthesis. Cutting down trees prevents this process from taking place ,therefore the concentration of carbon dioxide in the atmosphere increases.

  • Remember, cutting down trees does not release carbon dioxide, it only reduces the absorption of carbon dioxide on Earth through photosynthesis.

A Consequence of Global Warming

Ice Caps Melting and Sea Levels Rising

Global warming can lead to changes in habitats in which animals and plants live. An increase in temperature causes polar ice sheets and glaciers to melt faster than it can be made. At the same time, water expands when heated. The combination of these two factors, amongst others, results in rising sea levels.

Rising sea levels can lead to flooding and coastal erosion.