Global Change in the Earth System

Question 1

why does the Earth change constantly?

Answer 1

• tectonic plate motion
• closeness to a star
• liquid water allows for weathering and erosion
• biotic evolution modifies biosphere

Question 2

what is the Earth system composed of?

Answer 2

lithosphere, atmosphere, hydrosphere reacting with biosphere

Question 3

reminder: how did the moon form?

Answer 3

Mars-sized protoplanet collides
Mantle blasted into space
Debris coalesced to form the Moon

Question 4

reminder: what gases were found in ealry atmosphere?

Answer 4

CO2, H2O, N2.
water vapour condensed to form oceans
O2 appeared from photosynthesis

Question 5

when did life appear on Earth?

Answer 5

3.8 Ga.
multicellular appeared in late Proterozoic and early phanerozoic.

Question 6

what is the supercontinent cycle?

Answer 6

plate tectonics drive movement. ocean basins open and close. continental landmasses collide and rift apart.

Question 7

describe surface level cycle

Answer 7

SL rise: transgression (shore moves ladward)
SL fall: regression (shorelines move seaward)
preserved evidence of sea-level change in sedimentary rocks

Question 8

what are biogeochemical cycles?

Answer 8

Chemical fluxes between living and nonliving
Storage and transfer between reservoirs (nonliving and living)

Question 9

where is carbon stores in the lithosphere?

Answer 9

limestone
fossil fuels
organic shales
methane hydrates

Question 10

how is carbon returned to atmosphere? DORM

Answer 10

respiration
oxidation (burning) of organic matters
metamorphism of carbonate rocks
degassing (removing CO2 from water)

Question 11

how does the teacher describe the greenhouse effect?

Answer 11

H2O, CO2, and CH4 in Earth’s atmosphere absorb thermal
energy and reradiate it, warming the lower atmosphere

Question 12

what is paleo climate? think principle of uniformitarianism

Answer 12

looking at the past climate and predicting what will happen with the Earth’s future climate

Question 13

what is paleoclimatic evidence?

Answer 13

stratigraphic records (rock strata)
paleontological (faunal assemblages)
oxygen isotopes (16O and 18O)
growth rings (thicker = warmer, wetter and vice versa)

Question 14

Today, we live in an “Icehouse” but in an interglacial period in that icehouse

Question 15

what causes long-term climate changes? RECAP

Answer 15

• Plate tectonics (position of continents).
• Uplift of land surfaces (atmospheric circulation).
• Formation of coal and oil (less carbon from atmosphere).
• Evolution of life affected atmospheric composition.

Question 16

how is short-term climate change regulated?

Answer 16

• Fluctuations in solar radiation
  and cosmic rays
• Changes in orbit and tilt
• Changes in volcanic emissions
• Changes in ocean currents
• Changes in surface albedo
• changes in concentrations
  of greenhouse gases

Question 17

name when the 5 major extinctions occured. RECAP

Answer 17

Late Ordovician
Mid-Late Devonian
End Permian
Late Triassic.
End Cretaceous

Question 18

human impact on earth

Answer 18

• landscape modifications
• ecosystem modification (destabilized balance and destroyed habitats)
• pollution (smog, water contamination, acidification from sulfide, radioactive waste)
• hole in ozone layer
• ghg addition (CO2)

Question 19

how much will temperature increase in the future?

Answer 19

2050, average annual T will increase by 1.5 to 2.0
By 2150, global T could be 5 to 11 warmer than present.
Note: global temp is higher today than even during medieval warm period

Question 20

what to expect from global warming?

Answer 20

• stronger storms from more vigorous hydrologic cycle
• rise in sea level
• interruption of oceanic heat conveyor