The Earth's Atmosphere

Question 1

How old is Earth?

Answer 1

4.6 billion years

Question 2

What was the early atmosphere like (up to 2.7 billion years ago)?

Answer 2

Carbon dioxide highest - release by volcanoes
Little oxygen
Nitrogen - released by volcanoes
Water vapour - released by volcanoes, Earth too hot for it to condense
Ammonia, methane may also have been present

Question 3

Evidence 2.7-4.6 billion years ago

Answer 3

Very little

Question 4

What was the atmosphere like 2.7 billion years ago - 200 million years ago?

Answer 4

Carbon dioxide reduced because it dissolved in oceans, algae (and later plants) photosynthesised, precipitates in oceans as solid carbonates/ sediments that form rocks, taken in by plants and animals - the carbon is locked up as fossil fuels
Oxygen increased because of photosynthesis
Nitrogen increased - very stable so any process that produces it causes it to build up over time
Water vapour starts to decrease as water vapour condenses to form oceans

Question 5

What evidence was there 2.7 billion years ago - 200 million years ago?

Answer 5

Look at processes that happen today and make theories about the past

Question 6

What is the modern atmosphere like?

Answer 6

Carbon dioxide
Oxygen
Nitrogen
Water vapour - collects in clouds
Other gases, such as noble gases

Question 7

What evidence is there today?

Answer 7

Ice core evidence for millions of years ago along with recent global measurements

Question 8

What is the greenhouse effect?

Answer 8

Short wave radiation from the sun enters earths atmosphere which absorbs and reflects some radiation
Energy emitted by Earth is long wavelength radiation which is absorbed by greenhouse gases, trapping the energy and warming the Earth

Question 9

What is the importance of greenhouse gases?

Answer 9

Carbon dioxide, methane, water vapour
Absorb radiation and maintain temperatures

Question 10

Why have greenhouse gases increased?

Answer 10

Combustion
Deforestation
Rice fields
Cattle farming

Question 11

What is the evidence for global warming?

Answer 11

Peer review
Some people doubt

Question 12

What is climate change?

Answer 12

How the overall weather patterns over time change across the entire planet

Question 13

What are some effects of climate change?

Answer 13

Rising sea levels
Extreme weather events
Changes in the amount and time of rainfall
Changes to ecosystems and habitats
Polar ice caps melting

Question 14

What is carbon footprint?

Answer 14

The amount of carbon dioxide and methane released into the atmosphere by a product, person or process

Question 15

What is carbon monoxide?

Answer 15

Pollutant released during incomplete combustion which is a colourless and odourless toxic gas

Question 16

What are particulates?

Answer 16

Pollutant which can lead to global dimming and respiratory problems from incomplete combustion of fuels, especially in diesel engines

Question 17

What is sulfur dioxide and nitrogen oxides?

Answer 17

Sulfur impurities from fuel or nitrogen from the air reacting with oxygen in the engine to cause acid rain and respiratory problems

Question 18

How did nitrogen increase?

Answer 18

Ammonia reacted with oxygen