Greenhouse gases

What are greenhouse gases? What are some examples of greenhouse gases?

Greenhouse gases, such as carbon dioxide, methane and water vapour are present in small amount’s in the Earth’s atmosphere. They act like an insulating layer, keeping the Earth warm

Describe the greenhouse effect - How do greenhouse gases keep the Earth warm?

All particles absorb certain frequencies of radiation. The sun emits short wavelength electromagnetic radiation which passes through the Earth’s atmosphere, as it isn’t absorbed by greenhouse gases. The short wavelength radiation reaches the Earth’s surface, is absorbed, and then re - remitted as long wavelength, infrared radiation. The radiation is absorbed by greenhouse gases in the atmosphere. The greenhouse gases then re - radiate it in all directions - including back towards Earth. The infrared radiation is thermal radiation, so it warms the surface of the Earth. This is the greenhouse effect.

Describe the proportion to which every gas is present in the atmosphere.

The atmosphere is made up of 78% % of the atmosphere), mainly carbon dioxide, noble gases and water vapour

Why does global warming occur?

Increased levels of greenhouse gases in the atmosphere enhance the greenhouse effect as more IR radiation is absorbed and radiated back towards Earth, which causes the Earth to get warmer

How has increased energy consumption affected the greenhouse effect and global warming?

Over the last 150 years, the world’s human population has shot up and we’ve become more industrialised. Both of these factors mean that we’ve increased out energy consumption and are burning more and more fossil fuels. Burning more fossil fuels means that carbon, that was locked up in the fuels, has been released into the atmosphere in the form of CO₂.

How has deforestation affected global warming and the greenhouse effect?

More people also means more land is needed to build houses and grow food. We’ve been chopping down forests to create this extra space. This is a problem because plants absorb carbon dioxide by photosynthesis. So fewer plants means less carbon dioxide is being removed from the atmosphere.

How has methane and farming affected global warming and the greenhouse effect?

The greenhouse gas methane is also causing problems. Like carbon dioxide, the concentration of methane has also risen a lot in recent years due to increased human activity. E.g. farming cows and forming rice. Methane ia s highly effective greenhouse gas