Session 20 ( Paleoclimate)

Question 1

Paleoclimate

Answer 1

Measuring the earths climate prior to human existence

Question 2

Climate Proxies

Answer 2

indirect forms of evidence to infer climate.

Question 3

Commonly used proxies

Answer 3

• Sediments (fossils)
• Ice cores
• Tree rings
• lake varves
• coral bed rings
• Speleothems

Question 4

Dendrochronology (tree rings) (1000 years)

Answer 4

Wider rings = more growth. Vise Versa.

Question 5

Anoxic Lakes ( Varves) (Century- Millenium)

Answer 5

Runoff sediment composition.
Light = Mineral rich
Dark = Organic rich

Question 6

Speleothens (cave dripstones) (seasonal to millennium)

Answer 6

formed as a part of the meteoric water cycle

Question 7

Corals (100+ years)

Answer 7

Lighter shade show fast growth (summer) dark layers show slow growth (winter)

Question 8

Ice Cores (Poles) 800,000 years

Answer 8

Lighter layers in summer vs darker in winter

Question 9

When do Ice ages happen?

Answer 9

when CO2 concentrations are low

Question 10

Slow Carbon Cycle

Answer 10

Plates shift forcing CO2 from plankton to go under volcanos making them erupt and add more CO2 back into the atmosphere

Question 11

What can cause the sediments to have different colors?

Answer 11

Oceans became acidic from the PETM causing the color change

Question 12

Paleocene–Eocene Thermal Maximum (PETM)

Answer 12

a period of rapid global warming caused by a massive injection of carbon into the ocean and atmosphere

Question 13

What did PETM Cause

Answer 13

Caused rainforest to flourish but marine life struggled with intense ocean acidification causing loss in calcium.

Question 14

Methane Hydrates

Answer 14

Crystal like cages that enclose a methane molecules thriving at low temperature and high pressure.

Question 15

How did PETM affect Methane release

Answer 15

The intense heating of the ocean released methane into the atmosphere

Question 16

Milankovitch Cylces

Answer 16

Cycles of the sun and earth that cause warming and cooling in intervals over time

Question 17

Precision of Equinoxes

Answer 17

When the northern hemesphere is tilted away or towards the sun (19 and 23 KY)

Question 18

Aphelion

Answer 18

When the earth is furthest from the sun

Question 19

Perihelion

Answer 19

When the earth is closest to the sun

Question 20

Obliquity Cycle

Answer 20

Changes in tilt. More tilt will create more severe seasons and less tilt will create moderate seasons.

Question 21

What is the Atlantic Meridional Overturning Circulation (AMOC)

Answer 21

A system of ocean currents that form a vertical loop that extends the whole length of the atlantic moving warm water to the poles and cold water to the equator

Question 22

Why is AMOC reaching its tipping point

Answer 22

With ocean water becoming warmer, the AMOC weakens creating extreme weather

Question 23

How the AMOC effects europe

Answer 23

Causes very severe cold temperatures in the north and very hot in the south.

Question 24

What happens to the Antarctic ice sheet and southern polar jet stream because of AMOC

Answer 24

Causes warm water to stop going north and accumulates in the south causing western ice sheets to melt. Intense jet streams are caused due to the increase in temperture change between the poles and equator.

Question 25

Feedback loop for loss of ice in western Antarctica

Answer 25

Ice melts causing colder and less dense waters weakening the AMOC

Question 26

Upwelling

Answer 26

Cold, Deep, nutrient-rich water moving to the surface.

Question 27

Downwelling

Answer 27

Pushing water downwards

Question 28

Ekman Transport

Answer 28

Wind causes surface water to move, however, because of coriolis effect, it moves at a 40 degree angle.

Question 29

Net Transport in the NH

Answer 29

90 degrees to the right

Question 30

Net Transport in the SH

Answer 30

90 degrees to the left

Question 31

Winds heading north along the west coast cause it?

Answer 31

Downwelling because Ekman transport pushes currents toward the shore

Question 32

Winds heading south along the west coast cause what?

Answer 32

Upwelling because ekman transport pushes water away from the coast pushing currents away from the shore

Question 33

Atlantic Ocean Bifurcation

Answer 33

The Amoc shutting down due to icemelting and putting less dense freshwater at the surface

Question 34

Sterodynamic sea-
level variability

Answer 34

Changes in ocean circulation due to changes in temperature and salinity

Question 35

If the North of the North Atlantic
cools, why does that not
stimulate deepwater formation?

Answer 35

The water also needs to be dense enough to sink.

Question 36

What does a warming of the
Southern Atlantic Ocean imply
for the global meridional
overturning circulation?

Answer 36

altered weather patterns, regional cooling or warming effects, and changes in oceanic carbon storage.

Question 37

Which oxygen is lifted more with evaporation

Answer 37

O16

Question 38

Does a colder climate mean more O16 in ice or ocean?

Answer 38

In ICE because the O16 comes from the ocean through evaporation and builds up in the ice

Question 39

Does a Warmer climate mean more O16 in ice or ocean?

Answer 39

In the ocean because the Ice is melting