1. The greenhouse effect

2. How is the Earth warmed? Climate is affected by the conditions and components of the atmosphere. The Earth’s atmosphere acts like the glass in a greenhouse and is needed to keep the planet warm enough for life to exist. Sunlight passes through the Earth’s atmosphere and the Earth gives out infrared radiation. Certain gases trap some of this radiation in the atmosphere which keeps the Earth warm. This is called the greenhouse effect. Having some greenhouse gases is a good thing. If it wasn’t for these gases, Earth would be too cold to live on! However, too much of a good thing can be bad.

3. The greenhouse effect

5. How hot can the greenhouse effect get? The planet Venus is further from the Sun than Mercury but has an higher average temperature. Its surface can reach up to 482°C which is hot enough to melt lead! Venus’ atmosphere is mostly made up of carbon dioxide which traps so much of the solar radiation that the planet becomes extremely hot. The hostile climate conditions on Venus make it impossible for life to survive.

6. Greenhouse gases

7. What is global warming? The term ‘global warming’ is often used in connection with climate change but what does it mean? Global warming refers to the increase in the Earth’s temperature due to the greenhouse effect which can cause changes in climate. However, the term ‘global warming’ is now being used to refer to the warming predicted to occur as a result of increased emissions of greenhouse gases and other human activities. This enhanced greenhouse effect may lead to significant climate change. Remember, global warming and climate change are not the same thing and should not be used interchangeably.

8. Why is carbon dioxide so important? Carbon dioxide is considered the most significant greenhouse gas. This is because carbon dioxide can remain in the environment over a long time from 50 to 200 years. Any process producing carbon dioxide today could affect the climate for hundreds of years. Carbon is present in all living things and moves through the environment in a chain of reactions called the carbon cycle. Levels of carbon dioxide in the atmosphere have increased since the industrial revolution in the 19 th Century. How might human activities have contributed to this?