lecture 4 - long term controls on climate

Question 1

describe the faint young sun paradox in a short sentence:

Answer 1

The faint young Sun paradox refers to the contradiction between the Sun’s lower luminosity in its early years, which should have resulted in a colder if not frozen solid Earth, and geological evidence indicating that the planet had stable, warm conditions favourable to liquid water and life during that time.

Question 2

what are two simple solutions to the faint young sun paradox?

Answer 2

1. greenhouse affect has changed (thicker atmosphere with more greenhouse gases which leads to an increase in temperature)
2. atmosphere composition has changed

Question 3

what are some implications of changing solar luminosity?-

Answer 3

• earth’s climate is much more complex than simply being in the habitable zone
• atmospheric composition and greenhouse effect has changed over time

Question 4

what are some major carbon reservors?

Answer 4

• sediments and rocks
• deep ocean
• soil
• ocean mixed layer

Question 5

describe how temperature and rainfall control weathering

Answer 5

higher temperature and higher rainfall both lead to more weathering

Question 6

what are three factors which control weathering?

Answer 6

1. the position of continents
2. the size of continents
3. uplift

Question 7

how does the position of continents control weathering?

Answer 7

equatorial continents have higher weathering rates as it is warmer and they experience higher levels of rainfall.

this leads to cooler climates due to enhance CO2 removal via weathering

Question 8

how does the size of continents control weathering?

Answer 8

supercontinents like Pangea would have had very dry climates in the interior of the continent = lower weathering rates