Glaciers 3

Question 1

Explain the concept of glaciation

Answer 1

• the concept of glaciation took a long time before it was recognized
  -it has occurred several times over the course of history
  -glacial periods occurred during “cold periods” on earth
  -climate change (though it is extremely complex to analyze due to multiple factors(and because a lot of these factors are interrelated) this is the climate system)

Question 2

who proposed that the area that is covered in ice was once much greater

Answer 2

-Louis Agassiz
-based on erratic rocks

Question 3

What are some of the causes of glaciation? (3)

Answer 3

-orbital parameters/ Milankovitch cycles
-tectonic plates/ position of the continents
-among other factors

Question 4

Explain Milankovitch

Answer 4

-Milankovitch was an astrophysicist (he wanted to find an equation to model the earths climate changes, he mathematically demonstrated that the variations in the earths orbital parameters cause climate cycles due to changes in isolation)

Question 5

Explain Orbital Parameters

Answer 5

-more precisely the variations in the orbital parameters affect the degree of contrast between the seasons due to the distribution of solar radiation
-General Rule: mid winters+ more snowfall, cooler summers generate a reduction in snowmelt
-cyclicity is due to Eccentricity, Obliquity, Precession

Question 6

Explain Eccentricity

Answer 6

the quality of being eccentric (odd or out of the norm, no established pattern)
-eccentricity is the shape of the earths orbit around the sun
-varies from circular (0.0034) to elliptical (0.058) = this affects the overall distance from the Sun and, therefore, the total amount of solar energy Earth receives over a year
*currently almost circular (0.0167) so it is considered a more even orbit
(periodicity 100,000)

Question 7

Explain Obliquity

Answer 7

-the inclination/ tilt that the earths rotational axis makes with the plane of its orbit
-varies from 22.5 to 24.5
*currently 23.5 and going down
-0= no season, anything else means seasons (due to the hemisphere pointing at the sun receiving more insolation)
*more obliquity means bigger contrast between seasons
(periodicity 41,000)

Question 8

Explain Precession

Answer 8

-the gradual change in the direction of the earths rotational axis with respect to the sun
*aka the north pole wont always point in the same place
-eventually summer in the northern hemisphere will occur when the earth is closer to the sun, making summers hotter (switch canada’s seasons with australia’s)
(periodicity 26,000)

Question 9

What is Perihelion

Answer 9

when the earth is closest to the sun
*currently happens in january

Question 10

What is Aphelion

Answer 10

-when the earth is farthest from the sun
*currently happens in july

Question 11

What are the multiple climate impacts tectonic plates have on a global scale

Answer 11

1. position of the continents
   -albedo
   -weathering
   -ocean currents
2. volcanism

Question 12

Explain Albedo

Answer 12

-albedo is the proportion of the solar radiation that is reflected from a surface
-continents at the equator absorb more heat, which limits ice formation

Question 13

What is positive feedback-albedo

Answer 13

-amplifies change
-ice forms, albedo increases, more light is reflected, temps drop, more ice forms, repeat
-this accelerates cooling

Question 14

What is negative feedback-albedo

Answer 14

-dampens change
-ice melts, albedo decreases, more light absorbed, temp rises, stabilizes warming
-helps balance the climate systyle

Question 15

What is weathering

Answer 15

-the chemical alteration of the continental silicate rocks using CO2 (GHG)
-occurs most effectively between tropics (lots of heat and rain fall, CO2 levels drop, global cooling)

Question 16

Explain ocean currents and wind patterns

Answer 16

-they are important for transferring heat and moisture around the globe
-position of continents affects ocean currents
-topography affects wind patterns and precipitation (mountains = barriers, air has to rise (+cool) and then drop back down)

Question 17

Explain Volcanism as a cause of glaciation

Answer 17

-they emit tiny solid particles (like sulfur dioxide-sulfate particles), which form reflective clouds in the stratosphere (which means less light reaches earths surface)
-also over long term, volcanoes emit GHG (CO2), winch traps heat, and causes warming (reverses glaciation)
*mt Pinatubo 1991, 0.5

Question 18

What are the other factors that affect glaciation

Answer 18

-composition of the earths atmosphere
-solar activity
-biosphere
-humans
-cosmic rays

Question 19

Explain how the composition of the earths atmosphere affects glaciation

Answer 19

-the GHG in the atmosphere absorb and remit radiation
-most abundant: H2O, CO2, CH4
-GHG effect (warms earth)

Question 20

Explain how solar activity affects glaciation

Answer 20

-solar radiation increases by 7% every billion years
-sunspots have an 11 year cycle

Question 21

Explain how the biosphere affects glaciation

Answer 21

-it interacts with the atmosphere, hydrosphere and lithosphere
-vegetation emits water vapor through transpiration
-some organisms trap CO2 in rocks

Question 22

Explain how human activity affects glaciation

Answer 22

-emission of GHG (mostly CO2) through fossil fuels and the cement industry
-deforestation
-ozone depletion

Question 23

Explain how cosmic rays affect glaciation

Answer 23

-cosmic rays= formation of clouds
-clouds= reflection of solar radiation
*more cosmic rays means more clouds which means more solar reflection= lowering of temp
-the amount of cosmic rays that reach earth depends on: position of the solar system and solar activity (magnetic fields)