What is the Greenhouse effect?

Start by filling in our TWLH chart to help us identify what we know about the Greenhouse effect.

1. What we think we know

2. What we want to learn

3. What we learned.

4. How we know.

The greenhouse effect is the trapping of heat from the Sun in the Earth's atmosphere. This has the effect of warming the Earth and making our planet hospitable to life. Without a greenhouse effect, the Earth would be very cold, about -18°C rather than our current average of 15°C.

What is the Greenhouse effect?

What is your understanding of the Greenhouse effect? Draw a diagram to show how it works. When drawing the greenhouse effect you will need to consider these elements.

What does the Greenhouse effect look like?

• Sun

• Atmosphere

• Heat from the sun

• Earth

Mars once had running water on its surface and may have supported life. Now, with only a very thin atmosphere left and virtually no greenhouse effect, it is now so cold that the only water is underground or in the polar ice caps.

Venus, on the other hand, has an average surface temperature of 482°C due to its incredibly dense atmosphere and run-away greenhouse effect.

With too much of a greenhouse effect we would become another Venus, not enough and we would freeze like Mars! The Earth needs the greenhouse effect, but just the right amount.

If life on Earth exists because there is a greenhouse effect, what is all the fuss about?

About three-quarters of the greenhouse effect is due to water vapour in the form of clouds and moisture in the air, with carbon dioxide being the next most important gas. Over the past 200 years, additional carbon dioxide gas has been pumped into the atmosphere due to burning of fossil fuels and deforestation. Today, the concentration of carbon dioxide is approximately 28% greater than in the pre-industrial 18th century. Similarly, the other greenhouse gases have also increased because of human activities.

The higher the concentrations of greenhouse gases in the atmosphere, the more heat is trapped and the warmer the lower atmosphere (troposphere) is likely to become, changing weather patterns and climate.

This adds to the natural greenhouse effect, producing an enhanced greenhouse effect or global warming. The impact of an enhanced greenhouse effect on the climate has been of increasing concern to scientists over the past decade.

What is your understanding of the Greenhouse effect now? Draw a diagram to show how it works.

What does the Greenhouse effect look like?

Thankyou for your great work in the lesson today!

See you next time.