Lec 2

Question 1

Topography of the North

Answer 1

Northern areas vary vastly in elevation

Northern conditions are worse at higher elevations

Large areas of flat terrain with several mountains

Question 2

The Lomonosov ridge

Answer 2

Divides the arctic ocean into two major basins

Influences water circulation, marine life, and ice movement

Question 3

Geology importance

Answer 3

Biologically important in structuring drainage, soil, materials etc

Territorial claims

Question 4

Franklin Expedition

Answer 4

Trying to find a passage through the North, failed and left minerals

Question 5

Most sought after mineral

Answer 5

Diamonds

Question 6

Precambrian includes

Answer 6

Archean
Proterozoic

Question 7

Precambrian

Answer 7

Refers to 4.5 billion-543 million years

75 percent of Canada is Precambrian

Question 8

Canadian Shield

Answer 8

300-600 meter elevation

Can be 1070 meter elevation in Quebec and Labrador

Question 9

Igneous rocks

Answer 9

Rock of volcanic origin

Question 10

Sedimentary rock

Answer 10

Rock formed at or near Earth’s surface by the accumulation and lithification of sediments or by precipitation from solution at normal surface temp

Question 11

Metamorphic rock

Answer 11

Rocks that have been altered by a change of conditions

Question 12

Forests in the Arctic

Answer 12

Forests have been preserved due to mummification of litter, stumps, boles, roots, seeds, soils

Question 13

Milankovitch Cycles and Glaciation

Answer 13

Episodic glacial and interglacial periods within the present Ice Age (last couple of million years) have been caused primarily by cyclical changes in the Earth’s circumnavigation of the Sun

Question 14

3 components of the Milankovitch cycle

Answer 14

Eccentricity

Axial tilt

Precession

Question 15

Eccentricity

Answer 15

Shape of the Earth’s orbit around the sun

Prime importance to glaciation in that it alters the distance from the Earth and Sun

Question 16

Axial tilt

Answer 16

Today at about 23.5 degrees

Less axial tilt result in solar radiation more evenly distributed between winter and summer

Less tilt would promote glaciation

Question 17

Precession

Answer 17

Earth’s slow wobble as it spins on its axis

Question 18

What triggers an ice age

Answer 18

The amount of summer sunshine on northern continents is crucial

If it drops below a critical value, snow from the past winter does not melt away in the summer

Question 19

Milankovitch cycles and global warming

Answer 19

Have tremendous value as a theory to explain long term changes in climate

Unlikely to have much impact on the decade-century timescale

Measured over several centuries

For predicting climate change in the 21st century, they will be far less important than radiative forcing from greenhouse gases

Question 20

Nature geosciences

Answer 20

At the current atmospheric CO2, models show glaciation should not occur

Based on current orbital configuration, for glacial inception to occur CO2 would have to be less than the preindustrial levels

Exact CO2 threshold isn’t clear

Question 21

Greenhouse gases

Answer 21

CO2

Methane

N2O

SF6

Water

Question 22

Solar energy absorbed by Earth’s surface is emitted as

Answer 22

Weaker radiation with longer wavelengths (infrared range)

Question 23

What happens to infrared radiation

Answer 23

Some of it passes through the atmosphere, but a majority is absorbed by GHGs and then reemitted in all directions