System Earth Ch 15

Question 1

holocene epoch

Answer 1

the last 100,000 years

Question 2

palynology

Answer 2

the study of pollen in sediment to establish an estimate of the plant population in an area and thus determine the climate.

Question 3

what is radiocarbon dating used for?

Answer 3

date different levels of sediment coreto associate environmental change to certain periods. This is used in addition to palynology

Question 4

dendrochronology

Answer 4

the study of tree rings using both the number of rings and their characteristics to determine climate every year.

Question 5

since when do we have world wide accurate climate data?

Answer 5

1970

Question 6

since when do we have temperature data

Answer 6

1850

Question 7

where has temperature been affected the most in the last 1000 years?

Answer 7

mid and high latitudes

Question 8

where has moisture content been affected the most in the last 1000 years?

Answer 8

tropics and sub-tropics

Question 9

perspective on variability in temperature and the 20th century?

Answer 9

the small changes (eg. vikings) are fairly small (0.5K) but what we have predicted is similar to the change in temperature since the last ice age but then in the time scale of the next 100 years.

Question 10

describe the world in the holocene climatic optimum

Answer 10

very stable (5,000 to 6,000 yrs ago)
warmer summers globally
northward shift of ITCZ
much more rainfall in sahara and savannah regions.
enhanced monsoon circulation

Question 11

Medieval warm period

Answer 11

Greenland had farms in 1100
ended 1250-1350, sea ice expanded, lots of floods plus the plague, so 25% of Europe died

Question 12

The Little Ice Age

Answer 12

1500-1850
much cooler, especially in Europe

Question 13

causes of the little ice age

Answer 13

volcanoes and climate - lots of volcanoes in Iceland erupted
Solar variability

Question 14

sunspot cycles

Answer 14

every 11 years
sharp increase in temperature and gradual decrease
sunspots increase earth’s temperature because warmer area around sunspot is larger

Question 15

Maunder minimum

Answer 15

time of low sunspot activity

Question 16

Some main carbon sources, sinks, and storages

Answer 16

vegetation, soils and detritus, terrestrail NPP, volcanism, atmosphere, fossil fuels, surface ocean, marine biota, dissolved organic carbon, intermediate and deep ocean, surface sediment

Question 17

methane clathrate hydrate

Answer 17

CH4 in a lattice of H2O
organic matter decomposes anaerobically at great depths

Question 18

rate of fossil fuel burning

Answer 18

keeps increasing and is not distributed evenly through the world

Question 19

processes that remove CO2 from the atmosphere

Answer 19

reforestation
CO2 and N fertilization
dissolution in the oceans
dissolution of seafloor carbonate
weathering of continental rock

Question 20

reforestation

Answer 20

mainly in the northern hemisphere, photosynthesis is our friend

Question 21

CO2 and N fertilization

Answer 21

plants use water more efficiently under higher CO2 levels
if trees grow faster, they use more of the litter, which is wehere carbon is stored and thus there is less carbon stored in the ecosystem
nitrogen can be stored as nitric acid (acid rain) which fertilises plants. So increased rate of plant growth could be due to anthropogenic nitrogen emissions

Question 22

dissolution of CO2 in the oceans

Answer 22

slows down when there is more CO2 already in the ocean - has to penetrate deeper
this also increases the acidification of the oceans.

Question 23

dissolution of seafloor carbonates

Answer 23

in acidic oceans, the process of dissolution of carbonate sediments into the sea floor happens even faster. This is the long term sink for CO2.

Question 24

weathering of continental rocks

Answer 24

silicate + CO2 -> CaCO3 + SiO2
CO2 is stored nearly permanently in the rocks

Question 25

trace gases

Answer 25

methane and nitrous oxides

Question 26

radiative forcing

Answer 26

basically the model and how that affected the energy balance

Question 27

long-term climate warming

Answer 27

warming from an eightfold CO2 increase would make the earth warmer than it has been for tens of millions of year

Question 28

possible change in THC

Answer 28

melting of greenland ice sheet would stop deep sea formation and slow/ stop the THC in the North Atlantic, changing the existence of the gulf stream. But also, on a shorter time scale, you increase the rainfall, which also reduces the THC