Book 2 Flashcards
(92 cards)
What is outgoing radiation from the Earth a mixture of?
Reflected light and radiated heat
What is meant by the term ‘infrared active’?
A compound is infrared active if it absorbs long-wave infrared radiation owing to the way its molecules vibrate
What is meant by the term ‘albedo’?
A numerical measure of the reflectivity of a surface
What are the three astronomical cycles which can affect the amount of solar radiation hitting the Earth?
- Orbital eccentricity
- The tilt of the Earth’s axis
- Precession of the Earth’s axis
Which greenhouse gas makes the greatest contribution to global warming?
Water vapour
What is mean by the term ‘global warming potential’?
The relative contribution of a molecule of a greenhouse gas to atmospheric warming
What does the total warming effect of a greenhouse gas depend on?
- The quantity of the gas in the atmosphere
- How much infrared radiation a molecule of the gas can absorb
- How long the residence time is
What is meant by the term ‘residence time’?
The amount of time a gas stays in the atmosphere
What period of time is the Global Warming Potential (GWP) usually calculated over?
Between 20 and 500 years
What was the level of atmospheric carbon during the Industrial Revolution? What is the level of atmospheric carbon now?
- 280ppm
- 380ppm
What are some of the sources from which carbon moves into the atmosphere?
- Life forms
- Land-based sources (eg volcanic eruptions)
- The oceans
What are the three main ways carbon can be removed from the atmosphere?
- Photosynthesis
- Movement into oceans
- Geological processes which lock it into rocks
What are the two ways that carbon dioxide can be removed from living things?
- Respiration
- Combustion
Approximately how much carbon dioxide is annually sequestered by oceans?
90 Gt (gigatonnes)
Since 1750, approximately how much human-produced CO2 has been sequestered by oceans?
40%
What chemical effect does increased levels of CO2 have on oceans?
They become more acidic
What is the meaning of the term ‘dissociation’?
The breaking up of an ionic compound into its component ions
Increased ocean acidity especially effects which type of species?
How does it affect them?
- Crustaceans
- They make their shells from calcium carbonate - higher acidity inhibits calcification
What is the definition of the term ‘negative feedback’?
Change which serves to moderate change, so that the change is less than it would have been without the feedback
What is the definition of the term ‘positive feedback’?
Change which serves to enhance a change, so that the change is greater than it would have been without the feedback
What are the three Milankovic-Croll cycles?
- Orbital eccentricity
- Tilt of the Earth’s axis
- Precession of the Earth’s axis
What is meant by the term ‘orbital eccentricity’?
The yearly change of the Earth’s orbit from an elliptical shape to a more circular one, and back again
What does the tilt on the Earth’s axis vary between?
22.1 and 24.5 degrees
What is meant by the term ‘precession’?
The ‘wobble’ of the Earth on its axis