Chapter 13: Climate- Past, Present, Future

Question 1

What is the Faint Young Sun paradox?

Answer 1

The conundrum of a weak sun yet an watch warm enough to have an abundance of liquid water

Question 2

What is chemical weathering?

Answer 2

When acidic rain breaks down rock containing calcium

Question 3

How does chemical weathering remove CO2 from the atmosphere?

Answer 3

Acid rain breaks down calcium containing rock, which it then combines to form calcium carbonate, which will eventually make its way to the ocean where crustaceans will use it to build their shells.

Question 4

How could chemical weathering cool down climate?

Answer 4

By effectively removing CO2 from the atmosphere would reduce the GH effect and cool the climate down

Question 5

What is the Polar Position Hypothesis?

Answer 5

1. Ice sheets should appear on contents when located near the polar positions
2. No ice sheets should appear on continents that aren’t close to the poles

Question 6

What is the BLAG Hypothesis?

Answer 6

Most CO2 comes form volcanoes, and at this time there was rapid ocean floor spreading.
Therefore slow ocean floor spreading = a decrease in volcanoes and an overall decrease int he atmospheric CO2 content= cooler climate

Question 7

What is the Uplift Weathering Hypothesis?

Answer 7

The process of weathering rocks reduces CO2 in the atmosphere and cools climate

Question 8

What is the Ocean Heat Transport Hypothesis?

Answer 8

Sea levels control longterm Icehouse/Greenhouse climate.

-High seas cause warmer climates and low seas cause a cooler climate

Question 9

Where there ice sheets in the tropics back then? (evidence of a snowball earth)

Answer 9

There was some evidence but just barely. This allowed for there to still be liquid water oceans at the equator, more of a slushy consistency

Question 10

Why is the Eocene Epoch studied so hard?

Answer 10

Because of the similarities it has to what is happening today

Question 11

What is the Paleocene-Eocene Thermal Maximum (PETM)?

Answer 11

Superimposed on the upward side of the Eocene optimum is a narrow spike of very high temperatures which lasted for 20 000 years

• ocean temp rose 6C
• released a lot of carbon

Question 12

How can methane increase the global temp?

Answer 12

Methane clathrates at the bottom of the ocean are in a stable environment. If the temperature increases or pressure decreases, this will cause them to breakdown and release the gas

Question 13

What does the glacial/interglacial cycle correlate with?

Answer 13

Orbit changes

Question 14

What are millennial oscillations?

Answer 14

Climate events as short as 1000 yearend aren’t explained by the Milankovitch orbital factors

Question 15

What is the Younger Dryas Event?

Answer 15

Cooling event

Question 16

What caused the Younger Dryas Event?

Answer 16

Fresh water lakes formed in North America as glaciers retreated. Melt water would flow into the ocean, diluting it so that it would shutdown the natural ocean thermohaline system

Question 17

What is the little ice age?

Answer 17

Warm climate until 1400 where it got colder (only 1-1.5C colder than today). Milankovitch factors cased, and greenhouse losing tis strength

Question 18

What are the 3 hypothesis that could cause the millennial oscillation?

Answer 18

1. Processes within ice sheets: ice sheets get so big that they sink into the ocean, cooling climate
2. Interactions within the climate system: would have to respond to a forcing factor quickly
3. Solar variability external to climate system: depends on suns strength

Question 19

What is the origin of millennium oscillations?

Answer 19

May be correlated with periods of frequent ice rafting and or glacial melting

Question 20

Which periods produce the most change to climate?

Answer 20

Glacial periods

Question 21

What are the 2 primary processes that human do that contribute large volumes of CO2 to the atmosphere?

Answer 21

1. Deforestation/Clear cutting

2. Burning of fossil fuels

Question 22

What causes natural variation in CO2?/ Climate change?

Answer 22

1. Tectonic activity: can be ignored
2. Orbital Factors: Accounts for little change
3. Millennial factors: happen quick and make a big difference in a short period of time