Climate change causes

Question 1

Orbital changes

Answer 1

1) They affect how much solar radiation (energy) the Earth receives- more energy means more warming
2) There are various ways the Earth orbits the sun:
Stretch- The Earth’s orbit around the sun varies from circular to elliptical (oval-shaped). This is also called eccentricity.
Tilt- The Earth’s axis is tilted at an angle as it orbits the sun.
Wobble- The Earth’s axis wobbles like a spinning top ( this is known as precession).
These changes may have caused the glacial and interglacial cycles of the Quaternary period.

Question 2

Volcanic activity

Answer 2

1) Major volcanic eruptions eject large quantities of material into the atmosphere.
2) Some of these particles reflect the Sun’s rays back out of space, so the Earth’s surface cools.
3) Volcanic activity may cause short-term changes in climate, e.g. the Earth cooled by about 0.5 degrees after Mount Pinatubo erupted in 1991.

Question 3

Solar output

Answer 3

1) The Sun’s energy output isn’t constant- it changes in short cycles of about 11 years, and well possibly cycles hundreds of years long as well.
2) Reduced solar output means that the Earth’s climate may become cooler in some areas.
3) Solar output isn’t thought to have a major effect on global climate change.

Question 4

Human activities causing effects

Answer 4

1) In recent years, global temperatures have risen sharply, this is called global warming.
2) There’s a scientific consensus that human activity is causing global warming through the greenhouse effect.
3) The greenhouse effect takes place when greenhouse gases, such as carbon dioxide and methane, absorb outgoing heat from the Earth, so less is lost into space. It’s essential for keeping the planet warm.
4) However, if greenhouse gas levels increase, more energy is trapped and the planet warms up even more.
5) Humans are increasing the concentration of greenhouse gases in the atmosphere.

Question 5

How burning fossil fuels is damaging the environment

Answer 5

Carbon dioxide is released into the atmosphere when fossil fuels like coal, oil, natural gas and petrol re burnt, e.g. in thermal power stations or cars.

Question 6

How cement production is damaging the environment

Answer 6

Cement is made from limestone, which contains carbon. When cement is produced, lots of carbon dioxide is released into the atmosphere.

Question 7

How farming is damaging the environment

Answer 7

1) Farming livestock produces a lot of methane- cows love to belch.
2) Rice paddies contribute to global warming, because flooded fields emit methane.

Question 8

Deforestation

Answer 8

1) Plants remove carbon dioxide from the atmosphere and convert it into organic water using photosynthesis.
2) When trees are cut down, they stop taking in carbon dioxide.
3) Carbon dioxide is also released into the atmosphere when trees are burnt as fuel or to make way for agriculture.