Wikinotes

Maintainer: admin

atmosphere: exosphere -> thermosphere -> mesosphere -> stratosphere -> troposphere (http://upload.wikimedia.org/wikipedia/en/9/9a/EarthAtmosphereBig.jpg)
gas reflectors: aerosols (sulfates, soot, organic carbon, dust) in stratosphere, volcanic ash,
gas absorbers: co2
thermohaline circulation: conveyor belt

5 yr cycles
Reduced trade wind, warm water in pacific- El Nino
Opposite of El Nino La Nina
Arctic Oscillation - dominant pattern of non-seasonal sea-level pressure variations north of 20N

1) tectonic, volcanos (short term)
2) earth's orbit
3) sun strength (long term)/11 year sunspot activity (short term)
4) greenhouse gases (long term) - water, co2,
5) land use change (long term)
6) tropospheric aerosols (long term)
7) greenhouse gases (long term)

1) del atmosphere
2) del ice
3) del vegetation
4) del ocean
5) del land
6) thermohaline circulation (long term)
7) el nino (short term)

greenhouse affect: longwave heat radiation, not shortwave solar radiation

albedo: 31% (percent light reflected out)

CO2-> photosynthesis

respiration, temp, co2
soil water, evapotranspiration, precipitation
albedo, temp, snowcover

Spokesperson

From 1787-1832...
- the Swiss mountaineers
- Kuhn, Swiss Minister, erratic boulders sign of glaciation
- Hutton, Scottish Father of Modern Geology, erratic boulders sign of glaciation
- Parraudin, Swiss mountaineer/hunger, striations are caused by glaciers, clearly shown by receding glaciation aorund him
- Venetz, Swiss Engineer, characterized/systemized glaciar movements, deduced glaciers far more extensive
- Esmark, Norway Prof, deduced glaciers far more extensive
- Charpentier, German/Swiss geologist, categorized evidence (convinced by venetz)
- Bernhardi, German proff, paper: ice cap spread over europe

Charpentier showed him in person

One of most respected geologists at the time
believed that the "objective of geology was to confirm the evidence of natural religion and to show that the facts developed by it are consistent with the accounts of creation and deluge recorded by the mosaic writings of the bible"
important to win over

one trip to the mountains with Agassiz and a couple of years and then a second trip

founder of ice raft theory to explain both erratic boulders and ice-rafted boulders

Buckland convinced him by showing him some moraines
explained things he couldn't explain before

boulders were frozen in ice rafts in high lakes and drifted around
this truly happens and no contradiction lies here
since ice rafted boulders are not smooth, there is no evidence that they were carried by glaciers

Erratic Boulders: Giant boulders resting in a place far from their bedrock orign

boulders were frozen in icebergs and carried away

doesn't explain rocks at high altitudes

glaciers smoothed them out

glaciers scratched them as they moved over them

rocks seen when glaciers recently melted or rocks recently uncovered
very smooth, not caused by weathering (weathering erodes)

ice and smaller debris polished the rocks

makeup of the till doesn't match the bedrock: evidence of the extent of glaciers

terminal moraine

debris that is dumped by the glacier like a conveyor belt

lateral moraine

moraine is on the edges of glaciar

till

carried along by the glacier and melted at the end (in lateral moraines)

recessional moraine

periodic perpendicular ridges - caused by temporary halts

medial moraine

in center of valley where two glaciers meet

Lyell said techtonic activity caused it (higher altitude, lower temps)
James Geike said this was impossible, too slow

too minimal

no one knew co2 levels would've dropped

too temporary

see below

equinox: 12 hrs daylight, 12 hrs darkness everywhere (fall and spring)
summer solstice: longest day in the northern hemisphere
eccentricy: 100k-400k yrs
obliquity: 20-23 degree tilt, 41k yrs
precession: timing of seasons, shifts the solstices/equinoxes around the orbit every 21k yrs
tropics: lines of latitude that mark the tilt of the earth (i.e. change with obliquity)
perihelion: point at which earth is closest to sun
aphelion: point at which earth is furthest from sun

first to propose astronomical theory
'precession of the equinox' - whichever hemisphere had a longer winter would have an ice age
based on differences in number of hours of daylight in summer vs winter (i.e. long winters cause it)
had the eccentricity as a constant.

Jean le Rond D'Alembert: showed that equinoxes shift (winter in northern hemisphere is close to sun, but in 11k yrs, winter will be on the opposite side of the ellipse)

Alexander von Humboldt: avg temp is controlled by radiation, not by hrs of sunlight, so temp is still balanced out per year (radiation balances!)

precession AND ecentricty caused ice ages
thought that an extra cold winter could start an ice age
positive feedback
believed in hemispherical ice ages (if earth is far from sun, high eccentricity, and northern hemisphere is pointing away, precession, then ice age during the aphelion)
believed that if currents changed, moving war water/moisture/air away from north towards south, then this could amplify ice age

Geikie Bros: supported it cuz they had evidence that multiple ice ages occurred, as predicted by Lyell

Adhemar - read his book in a library 25 yrs later
Le Verrier - published on eccentricity

Charles Lyell - Croll said 80-150k year cycles, but Lyell found evidence at Niagra falls showing 30k
Newton Winchell - 10k-15k evidence (mississippi)

precession, eccentricty, and axial tilt
cooler summer in high latitudes responsible (less ice melting)
goal 1: geometry of orbit and how it changed over time
goal 2: calculate how much solar radiation strikes the surface (each planet, each season, each latitude)
goal 3: mathematical models of earth's past climates (650k yrs back at 55, 60, 65 lines)
goal 4: feedback: how much ice sheets would respond to change in solar radiation

wladimir Koppen: climate zones: "reduction of heat during summer was decisive factor in causing glaciation", matched euro erosion with mil's cycles
Alfred Wegener: Continental drift, cited Mil in "Climates of Geological Past"
Albert Penck and Eduard Bruckner: Mil's graph matched well with these guys glacier history maps

Adhmar, Croll
Ludwig Pilgrim: did most of the calculations 7 yrs earlier

Ingo Shafer - fossils in alpine terrace dated to contradict Mil's ice age - impossible for mollusks in an ice age
Meteorologists - theory failed to incorporate role of atmosphere and ocean
Richard Flint and Meyer Rubin - radiocarbon dating: ice sheet reached maximum extent 18k yrs ago
Discovery of 25k yr old peat layer in illinois shattered Milakovitch thoery

New Guinea terraces (top to bottom: 125k, 105k, and 82k) lined well with Mil's warm periods at 45 deg North (not at 65 deg North, where Mil had 40k year cycle, didn't predict 105k)
Mil's theory should place more emphasis on precession
players: Matthews, Brown University, New Guinea; Broecker: fossil reefs (florida keys), found 80k and 120k, matches Matthews' New Guinea data to Mil

Brickards
Players: Bernard Brunhes (Brickyards) and Matuyama
Now possible to date any core that had a magnetic signal
Potassium-Argon dating

5 soil-Loess cycle matching w/5 magnetic reversals: 100k yrs,
Loess: from outwash streams of glaciers
Kukla concluded: "cooling phase of climatic cycle lasted much longer than the warming phase. transitions from dusty polar desert phases to deciduous forest pahses were soabrupt that they appeared in the quarry walls as distinct lines"
proved Penck+Bruckner, and Koppen+Wegner wrong
"Mesolella at Brown and Kuukla in Czech found ways of modifying Milankovitch theory to account for 100k cycle. Both pointed out that the dominant cycle in the eccentricty curves (close to 100k) was a good match for climatic pulse
intensity of radiation during a season: precession
amplitude of radiation: eccentricity
Mesolella: summer was critical season
Kukla: Winter radiation critical

Two objectives:
- 1) Map earth's surface over last ice age
- 2) Measure Pleistocene Oscillations
  
  Pleistocene
  
  period of repeated glaciations (as many as 11 large ones)
  
  Holocene
  
  after Pleistocene, -11,700 yrs to today - no glaciation
  
  Pleistocene Interglacial
  
  any period where oak and other deciduous trees are widespread in europe
  
  Start of Pleistocene
  
  date at which oldest cold water fossil found (1.8 million years ago)
  
  Age of earth
  
  4.6 billion years
  
  Age of oceans
  
  3.8 billion years
  
  Age of dinosaurs
  
  65 million years ago
Results - - 1) climate oscillations have 4 frequency components: 41k axial tilt, 23k and 19k precession, 100k eccentricity
- Imbrie: ice sheets lag 8k years behind axial tilt
- ice sheets also lag behind 23k precession cycle

Terminal Moraine: pile of till that marks the furthest extent of the ice sheet or glaciar
Kettle ponds: lakes formed by melted icebergs (carried by outwash streams)
esker: long 'railway like' deposits left by streams flowing under glaciers
drumlin: almond shape formed by receding glacier

arete: ridge between two valleys (caused by, respectively, two receding glaciers)
horn: point
cirque: valley carved out into a bowl (think circus -> amphitheater)
hanging valley: waterfall: light glacier runs into heavy glacier
glacial lakes: form in cirques or behind/between recessional moraines

eustasy: global rise in sea level (due to polar ice caps) - think 'ecstatic about flordia drowning'
isostasy: rebound of lithosphere (land) in response to weight of ice sheets removed
lake champlain formation
; result of isostasy - used to be salt water
cordilleran ice sheet: north america, eastern side connected with laurentide ice sheet.
lake missoula: formed behind ice dam, emptied suddenly, connected to cordilleran ice sheet
glacier ice dam flooding: may be result of many great floods recorded in history

refugia: area untouched by glaciers - place where plants/animals live
south america migration: last continent, 10k yrs ago
hawai'i migration: 300 AD
Fiji migration: 1500 BC
New Zealand: 1000 AD
Canada/US Migration: 12k yrs ago

Asia Migration
:30k yrs ago

1350-1850
2-3 degree C change
high weather volatility

900-1300, 7 degrees warmer than today
Optimism, cereal grains, <3 God
Viking migration, Newfoundland migration, Swedes to russia

Less radiation (only 0.5%)
Sulfur deposits (volcanos)
Thermohaline circulation stopping due to influx of fresh water (normally surface currents from equator to the north)

Maunder Minimum

Temp decrease in middle of lil ice age: due to decreased sunspots
1645-1715

1315-1320: Extreme rain
1.5 mil died in famine
cereal died

settled during warm period
food: pre ice age: 20% marine, 80% land. Ice age: 20% land, 80% marine (land animals died + erosion + fragile land)
failed to adapt to inuits (who had excellent fishing techniques)
Massive deforestation
Also made it over to the tip of newfoundland (seasonal settlement, animals kept inside houses)
Inuits migrated from Northern Canada to Greenland
= No cargo ships from Norway
Vikings sucessful cuz 1) great ships and 2) predictable climate
Leif sailed westward to northern newfoundland

settled in 864 - not during warm period
Eric the Red kicked out of iceland, moved to greenland

experienced cool period during the warm period
Southwest US
experienced drought, crop failures, overpopulation

Frost fair on River Thames (1607-1814) - London
Washington cross delaware
Hudson River frozen (Manhattan $\rightarrow$ Long Island

Cereal $\rightarrow$ potatoes (UK)
Farming economy (veggies for meat)
France + Pope Innocent didn't like potatoes
Unable to burn potato farms in war
Irish potato monoculture $\rightarrow$ potato famine
More resistant (cold, wet, dry) and more diverse

Varnish, hard wood (maunder minimum), geometry

production of decreased in northern europe $\rightarrow$ northern europeans migrated to america
vines 300 south to where they were in warm period
American Immigrants: English, Irish, Scots, Dutch, Swedes, Poles

Napolean (snow in September)
Spanish Armada
American Revolution
victory or defeat often is hinged on climate

1787: coldest winter
french wanted bread, grain, and cereal

Most powerful volcanic eruption
Caused 'year without a summer'
brown snow in italy

loudest sound in history
temp dropped 1.2 degrees

Ash fallout
French revolution 6 yrs later
Coldest winter on record
killed quarter of population in Iceland (Iceland population not stable until after WW2)
Sulfur didn't circulate to southern hemisphere

Agaissiz presented theory of ice age when glaciers were receding

perhaps fewer volcanos
perhaps greenhouse gas fluctation
perhaps natural fluctuation in thermohaline circulation
perhaps less radiation

younger dryas: cold snap 11k years ago, lasted 1.2k yrs. freshwater influx stopped thermohaline circulation

1) Central New World - [corn, bean, potato, yam, squash, banana, llama, dog, pig, turkey]
2) Middle East - [wheat, barley, lentils, pea, pig, goat, donkey, horse, camel, dog, chicken]
3) China - [rice, soybean, millet, yam, pig, chicken, water buffalo]

1) clovus point spear
2) ice age ending
3) disease

some definitions

1Dr Heumann's Lectures¶

1.1Thermohaline circulation¶

1.1.1Greenhouse gases¶

1.1.2El Nino, La Nina, and Arctic Oscillation¶

1.1.3Causes for short + long term climate change in last 200 yrs¶

1.1.3.1external¶

1.1.3.2internal¶

1.1.3.3long term¶

1.1.4Solar radiation effects and sunspot activity¶

1.1.5Energy distribution of Earth's surface¶

1.1.6Negative Feedback¶

1.1.7Positive feedback¶

1.2The Players¶

1.2.1Louis Aggasiz¶

1.2.1.1Significance¶

1.2.1.2Work he expanded on¶

1.2.1.3What won him over¶

1.2.2Reverend Professor William Buckland¶

1.2.2.1Significance¶

1.2.2.2what won him over¶

1.2.3Charles Lyell¶

1.2.3.1Significance¶

1.2.3.2what won him over¶

1.3Early Evidence¶

1.3.1Ice-Rafted Boulders¶

1.3.1.1Flood Explanation¶

1.3.2Erratic Boulders¶

1.3.2.1Flood Explanation¶

1.3.2.2Flood Contradiction¶

1.3.2.3Glaciar Explanation¶

1.3.3Striated rocks¶

1.3.3.1Glaciar Explanation¶

1.3.4polished rocks¶

1.3.4.1glaciar explanation¶

1.3.5moraines¶

1.4evidence¶

1.4.1tectonic¶

1.4.2sunspots¶

1.4.3co2 levels¶

1.4.4volcanic eruptions¶

1.4.5astronomical theory¶

1.4.6astronomical theory¶

1.4.6.1definitions¶

1.4.6.2Adhemar¶

1.4.6.2.1Role¶

1.4.6.2.2built on¶

1.4.6.2.3nay sayers¶

1.4.6.3James Croll¶

1.4.6.3.1Roles/beliefs¶

1.4.6.3.2Supporters¶

1.4.6.3.3Built upon¶

1.4.6.3.4Nay sayers¶

1.4.6.4Milankovitch¶

1.4.6.4.1Roles/beliefs¶

1.4.6.4.2supporters¶

1.4.6.4.3built work on¶

1.4.6.4.4nay sayers¶

1.5revival of Milaknovitch¶

1.5.1Sea Terraces¶

1.5.2Magnetic Timeline¶

1.5.3Loess and George Kukla¶

1.5.4Climate Project: Hayes and Imbrie¶

1.6geography¶

1.6.1Laurentide ice sheet (North America)¶

1.6.1.1landscape features¶

1.6.1.2alpine glacier features¶

1.6.1.3Other definitions/ideas¶

1.7human migration¶

1.8Little Ice Age¶

1.8.1Background¶

1.8.2Warm period¶

1.8.3Causes of Lil Ice Age¶

1.8.4Beginnings of Lil Ice Age¶

1.8.5Greenland + Vikings + Newfoundland¶

1.8.6Iceland¶

1.8.7Anasazi¶

1.8.8Rivers¶

1.8.9Agriculture¶

1.8.10Violin¶