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©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
PaleoclimatologyRedistribution of oxygen isotopes:
Interglacial
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Vostok
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©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Natural Causes for Climate ChangeNatural Causes for Climate Change
1. Solar Fluctuations
2. Orbital Fluctuations
3. Volcanic Emissions
4. Plate Tectonics
5. Changing Ocean Circulation
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Solar Fluctuations
QuickTime™ and aSorenson Video decompressorare needed to see this picture.
Solar Fluctuat
ion
Solar Fluctuat
ion
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Milankovitch theory of climate change:
Eccentricity: 400
ka and 100 ka
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Energy Budget
animate
Shortwave energy per square meter will decrease at lower sun angles and shorter daylight
periods.
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Milankovitch theory of climate change:
Obliquity: 41 ka
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Milankovitch theory of climate change:
Axial Precessio
n: 23 ka
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Milankovitch theory of climate change:
Glacial
Ice Growth Configuration: High eccentricityHigh TiltSmall Earth-Sun Distance in Summer
Net Effect: More seasonal contrast
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Milankovitch theory of climate change:
Inter- Glacial
Ice Growth Configuration: Low eccentricityLow TiltLarge Earth-Sun Distance in Summer
Net Effect: Less seasonal contrast
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Climate ModelsGOOD NEWS: It has been possible to reproduce past climates using Milankovitch theory plus changes observed in greenhouse gas concentrations.
BAD NEWS: Changes were slow and we have little experience modeling rapid change.
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Climate Models
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
180
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280
300
320
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380
12500 10000 7500 5000 2500 0
Age (yr BP)
Taylor Dome
180
200
220
240
260
280
300
320
340
360
380
Age (kyr BP)
0100200300400
Changes in CO2 (0 - 12,500 YBP)
Paleoclimatology
NOW
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Energy Budget
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Climate
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
ClimateGlacial retreat of North American ice sheets (1000s of years)
Glacial retreat of North American ice sheets (1000s of years)
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Sea Level Change1-meter rise of sea level equivalent to 0.4 million cubic kilometers of ice
1-meter rise of sea level equivalent to 0.4 million cubic kilometers of ice
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Sea Level Change
1-meter rise of sea level equivalent to 0.4 million cubic kilometers of ice
1-meter rise of sea level equivalent to 0.4 million cubic kilometers of ice
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
RAPIDChanges
in ClimateHappen
Climate
Warmer
Cooler
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
Climate
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
ClimateCaCO3shells of ocean plankton from the Norwegian Sea and the Gulf of Mexico record pulses of low 18O meltwater delivery from nearby ice sheets.
[from Ruddiman, 2001]
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
ClimateCaCO3shells of ocean plankton from the Norwegian Sea and the Gulf of Mexico record pulses of low 18O meltwater delivery from nearby ice sheets.
[from Ruddiman, 2001]
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
ClimateDuring deglaciation the direction of drainage changed.
[from Ruddiman, 2001]
©2004, Perry Samson, University of Michigan
Natural Fluctuations in Climate
Natural Climate
Summary
Rapid Change
Issues
Paleoclimate
ClimateCaCO3shells of ocean plankton from the Norwegian Sea and the Gulf of Mexico record pulses of low 18O meltwater delivery from nearby ice sheets.
[from Ruddiman, 2001]
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