P2d

Question 1

How does the greenhouse effect work?

Answer 1

• Earth absorbs short wavelengths of EM radiation from Sun
• the earth emits long wavelength infrared radiation
• a lot is absorbed by atmospheric gases, CO2, methane and water vapour
• gases re-radiated heat in all directions, including back to earth
• the atmosphere acts as an insulating layer to stop the earth getting cold at night

Question 2

How have humans caused an increase in the amount of greenhouses gases?

Answer 2

• carbon dioxide: burning fossil fuels, chopping down and burning trees for space
• methane:decaying waste in landfill sites, cattle farming has increases and cattle digestion produces methane

Question 3

How does the greenhouse effect affect the climate?

Answer 3

• global temperature has risen (global warming)

- global warming leads to other climate changes, e.g. weather changes: warmer water means more hurricanes

Question 4

What are the humans causes of weather changes?

Answer 4

• rising levels of CO2 from burning fossil fuels causes the green house effect and global warming
• soot and gases produced by factories can reflect heat back down to Earth, increasing local temperature

Question 5

What are the natural causes of weather changes?

Answer 5

• ash and gases from volcanoes can reflect radiation from the Sun back into space, cooling down the earth
• changes in our orbit can cause ice ages

Question 6

How do changes in the weather affect food production?

Answer 6

• regions become too dry to grow food, others too wet

- this will get worse as temperatures increase and weather patterns change more