Chapter 13 - Earth's atmosphere

Question 1

For how long has the atmosphere’s balance of gases been the same as today’s?

Answer 1

200 million years

Question 2

Why is it difficult to be certain about the composition of the early atmosphere?

Answer 2

Evidence is limited for the early atmosphere due to the time scale of 4.6 billion years.

Question 3

What gases did volcanoes produce?

Answer 3

Water vapour, Carbon dioxide, Nitrogen, Methane and Ammonia

Question 4

Why is there such a high proportion of Nitrogen?

Answer 4

Nitrogen is a noble gas, so it is very unreactive.

Question 5

How did the amount of oxygen increase?

Answer 5

2.7 billions years ago, algae produced oxygen via photosynthesis, and a billion years later, plants evolved, and the amount of oxygen increased rapidly.

Question 6

How did the amount of carbon dioxide decrease?

Answer 6

1. Carbon dioxide dissolved in the oceans
2. Carbon dioxide was locked up in fossil fuels
3. Deposits of skeletons and shells formed sedimentary rocks, such as limestone

Question 7

What is the greenhouse effect, in terms of long and short wavelength radiation?

Answer 7

Greenhouse gases let short wavelength (e.g. UV) pass through. The Earth cools down by emitting longer wavelength infrared radiation, but some of this is absorbed by the greenhouse gases. The radiation stimulates the bonds in these molecules to move more vigorously - raising the air temperature.

Question 8

What are the two main human activities that contribute to the increase in Carbon dioxide levels?

Answer 8

1. Deforestation

2. Fossil fuels

Question 9

What are the two main human activities that contribute to the increase in Methane levels?

Answer 9

1. Swamps and rice fields

2. Cattle flatulence

Question 10

What are the 4 main potential effects of global climate change?

Answer 10

1. Rising sea levels threatens habitats
2. Increasingly common extreme weather events
3. Changes in rainfall patterns could produce floods and droughts
4. Changes to the distribution

Question 11

What is your carbon footprint?

Answer 11

The carbon footprint of a product, service or event is the total amount of carbon dioxide, and other greenhouse gases emitted over its full life cycle.

Question 12

What can be done to reduce your carbon footprint?

Answer 12

1. Use less fossil fuels
2. Develop Carbon Capture and Storage methods
3. Less demand for beef reduces methane levels
4. Develop electric cars
5. Buy locally sourced fruit

Question 13

How is Sulphur dioxide produced, and what are the consequences?

Answer 13

Created due to the oxidation of Sulphur impurities in fossil fuels. Causes acid rain.

Question 14

How is Nitrogen oxide produced, and what are the consequences?

Answer 14

Created due to the oxidation of Nitrogen gas in air at high temperatures in vehicle engines. Causes acid rain.

Question 15

How are particulates produced, and what are the consequences?

Answer 15

Created due to burning diesel. Causes global dimming.