C13 - Atmosphere

Question 1

C13 - Earth’s early atmosphere

Answer 1

Similar to the atmosphere of mars

Mostly carbon dioxide

Small amounts of nitrogen

No oxygen

Question 2

C13 - Earth’s current atmosphere

Answer 2

78% nitrogen

21% oxygen

0.04% carbon dioxide

Question 3

C13 - Evolution of Earth’s atmosphere

Answer 3

Early volcanic activity produced the atmosphere

As the Earth cooled, water vapour condensed to from oceans

Evolution of algae 2.7billion years ago oxygenated the planet

Over the next few billion years oxygen levels increase

Carbon dioxide levels decrease as it is absorbed by plants and as it is incorporated into the tissues of living organisms

Question 4

C13 - Explain how the earth’s atmosphere evolved

Answer 4

Early atmosphere mostly carbon dioxide and little oxygen - due to volcanic activity.

Nitrogen produced by volcanoes gradually builds up in atmosphere.

The water vapour from volcanic eruptions condensed to form oceans.

Carbon dioxide dissolved in ocean water reducing the carbon dioxide in the atmosphere.

Algae evolved and produced the first oxygen.

Plants evolved and percentage of oxygen increased. This increases to a level that enables animals to evolve.

Question 5

C13 - Greenhouse gases

Answer 5

Carbon dioxide - from respiration and combustion (burning fossil fuels)

Methane - from swamps, rice fields, landfill sites and grazing cattle

Levels off both of these gases are increasing

Question 6

C13 - Explain how the greenhouse effect causes an increase in global temperatures.

Answer 6

Radiation from the sun enters the earth’s atmosphere and warms the surface of the planet.

The earth’s surface becomes hotter and radiates heat back out.

Some of this heat is absorbed by greenhouse gases. These gases then radiate the heat back towards earth.

The atmosphere becomes hotter as a result.

Question 7

C13 - What are the effects of global warming

Answer 7

Loss of habitat

Changes in distribution

Changes in migration patterns

Reduced biodiversity

Question 8

C13 - solving global warming

Answer 8

Carbon footprint: the total amount of carbon dioxide and other greenhouse gases released over the life cycle of a product

Carbon capture and storage: pumping carbon dioxide from fossil fuel power stations deep underground to be absorbed into porous rock.

Reduced demand for beef: this would reduce the amount of grazing cattle and thus the amount of methane.

Biofuels: carbon neutral fuels that lead to no net increase in carbon dioxide levels.