Climate, Character and Causes of Climate Change

Question 1

What are the three geological time periods that we are mostly concerned with?

Answer 1

1. Eocene
2. Pleistocene
3. Holocene

Question 2

What are the three main characteristics of the Early Eocene maximum?

Answer 2

1. Deep ocean temperatures of roughly 16°C
2. Fossil palm trees and reptiles above the Artctic circle
3. Ice free

Question 3

What are the three main characteristics of the Pleistocene?

Answer 3

1. Glacial-interglacial cycles
2. Referred to as the LGM (last glacial maximum)
3. Several fluctuations of climate, including the Younger Dryas

Question 4

What are the three reasons for why the last 65 million years experienced gradual cooling?

Answer 4

1. Less CO2 in the atmosphere due to declining volcanism
2. Removal of CO2 due to weathering
3. Ocean transport of heat has changed with the changing quantity, size, and shape of continents

Question 5

What are glacial cycles, and what causes them?

Answer 5

Glacial cycles are periods of slow cooling and rapid ice melt which produces a sawtooth pattern on graphs

They are caused by temperature fluctuations (roughly 10°C) and CO2 fluctuations (180ppm - 300ppm)

Question 6

What four climate characteristics were typical of glacial periods, and how long did they last?

Answer 6

1. Windy
2. Cold
3. Arid
4. Dusty
5. For roughly 40,000 - 100,000 years

Question 7

What are the three components of the Milankovitch cycle?

Answer 7

1. Earth’s eccentricity (orbit)
2. Tilt/obliquity
3. Precision (wobble of axis)

Question 8

Why might the Milankovitch cycle explain glacial and interglacial periods?

Answer 8

The cycle modulates the strength and distribution of solar energy by small amounts which may result in significant climatic changes to the Earth’s surface

Question 9

What are the five components/timescales of the Earth’s climate system?

Answer 9

1. Atmosphere
2. Ocean
3. Ice
4. Solid Earth
5. Biosphere

Question 10

How is energy stored in the atmosphere?

Answer 10

Clouds (hours), winds (day), mid-latitude storms (days)

Question 11

How is energy stored in the ocean?

Answer 11

Stored at different depths in the ocean, with only its surface being in contact with the atmosphere. Storage times of up to 1000 years

Question 12

How is energy stored in ice?

Answer 12

Stores signals from the atmosphere in the form of gases or fossilised material. Ice accumulates or melts depending on seasonal patterns of up to thousands of years

Question 13

What two ways is energy stored in the solid earth?

Answer 13

Weather from CO2 in the atmosphere and percipitation due to terrain

Plate tectonics from changing ocean currents, solar radiation on land or ocean, and volcanism

Ranges from thousands to millions of years

Question 14

How is energy stored in the biosphere?

Answer 14

Plants modify solar radiation and atmospheric gases

Question 15

What are are the four components of the two positive climate feedback loops (pushes climate away from current state)?

Answer 15

More ice → Greater albedo → Lower temperatures → More ice

OR

Less ice → Lower albedo → Higher temperatures → Less ice

Question 16

What are the three components of the negative climate feedback loop (keeps climate at current state)?

Answer 16

Higher surface temperatures → More Shortwave radiation → Lower surface temperatures

Question 17

What are the three significant climate events that have occured since the LGM?

Answer 17

1. Younger Dryas
2. Medieval Climate Anomaly
3. Little Ice Age

Question 18

What four aspects of climate changed during the Younger Dryas?

Answer 18

1. Retreating Laurentide ice sheet
2. Melt water released in North Atlantic
3. Reduced ocean overturning circulation
4. Reduced ocean heat transport cooled climate

Question 19

Medieval Climate Anomaly

Answer 19

A warming event that occured mostly in the North Atlantic for roughly 300 years during the advent of the second millenium. During this time, temperatures rose by about 0.5°C, possibly due to reduced volcanism or changes in ocean circulation

Question 20

Little Ice Age

Answer 20

A global cold period that occured during the second half of the second millenium where temperatures decreased and fluctuated by about -0.5°C, possbily due to solar variability or volcanism

Question 21

What two events were caused by the Little Ice Age?

Answer 21

The Year Europe Froze (1709)
The Year Without Summer (1916)

Question 22

What affect do volcanic eruptions have on global temperatures?

Answer 22

Volcanic events put sulphur gases in the stratosphere. These sulphur aerosols reflect solar radiation, cooling the Earth