climatology and paleoclimatology paleoclimate summary climate issues
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Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
QUIZ!
Last Updated: April 18, 2023
On a scale of 0 - 10:
The ozone hole and global warming are related.
0No way!
10You Betcha!
5Coward
0
5
10
15
20
25
30
35
0 1 2 3 4 5 6 7 8 9 10
(No way!) 0 - 10 (You Betcha)
NUMBER
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
QUIZ!
Last Updated: April 18, 2023
On a scale of 0 - 10:
We are currently in a cool period of climate.
0How quickly
you forgetsummer.
10COOL!
5Who knows?I’ve got my
air conditioneron!
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues Driving Questions
1. How do we know that the composition of the atmosphere has changed in the past?
2. Ignoring greenhouse gas emissions what climate changes might we expect next?
Today’s Issues:
Last Updated: April 18, 2023
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues Climate has
changed quite
naturally over time
Today’s Issues:
Last Updated: April 18, 2023
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues Methods for
establishing past
temperatures
• Isotopic Geochemical Studies: The study of rock isotopic ratios, ice core bubbles, etc.
• Dendochronology: the study of tree rings
• Pollen Distribution: the study of plant types and prevalence
• Lake Varves: (like dendochronology, but with lake sediments)
• Coral Bed Rings
• Fossils: Studies of geological settings, etc.
• Historical documents, paintings, etc.
Today’s Issues:
Last Updated: April 18, 2023
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
Paleoclimatology
“Heavy” oxygen happens…
Isotropic Geochemi
cal Studies
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
PaleoclimatologyDating
Through Oxygen Isotope Ratios
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
PaleoclimatologyDating
Through Oxygen Isotope Ratios
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
Paleoclimatology
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
Vostok Record18O is well correlated
with temperature!
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
Sea Sediments18O in sea
sediments is used to
suggest temperatu
re
Seawater 18O variations over time can be linked to the growth and decay of ice sheets. During the last ice age sea level was ~130m lower than today reflecting about 3% of the ocean's volume. Consequently the 18O of the ocean was ~1.2 permille heavier (higher) than it is today.
Measuring the 18O in foraminifera allows to reconstruct past variations in the size of the ice sheets over millions of years.
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
Milankovitch theory of climate change
Eccentricity: 400 ka and 100 ka
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues Obliquity: 41 ka
Milankovitch theory of climate change
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues Axial Precessio
n: 23 ka
Milankovitch theory of climate change
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
Paleoclimatology
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues Glacial
Milankovitch theory of climate change
Ice Growth Configuration: Low eccentricityLow TiltLarge Earth-Sun Distance in Summer
Net Effect: Less seasonal contrast
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues Inter-Glacial
Milankovitch theory of climate change
Ice Growth Configuration: High eccentricityHigh TiltSmall Earth-Sun Distance in Summer
Net Effect: More seasonal contrast
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
Milankovitch theory of climate change
Take-away: Variations in our orbit begin to explain the variation in temperature over scales of >10,000 years.
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues Changes in CO2 (0 - 500,000,000 YBP)
Paleoclimatology
Geochemically inferred.
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Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues Changes in CO2 (0 - 25,000,000 YBP)
Paleoclimatology
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Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
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Paleoclimatology
VostokNOW
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
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Paleoclimatology
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Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
Lessons from Vostok
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
Lessons from Vostok
1. Past changes in climate have often been triggered by changes in orbital characteristics.
2. These initial changes are then amplified by changes in CO2 and CH4 concentrations.
3. The changes in greenhouse gas concentrations then exaggerate the temperature changes over the earth.
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
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Changes in CO2 (0 - 12,500 YBP)
Paleoclimatology
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Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues RAPIDChanges
in ClimateHappen
Climate
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
RADIATION
TEMPERATURE
ICE VOLUME
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
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Paleoclimate
Summary
Climate
Issues
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Paleoclimatology
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Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
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Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
SummaryDriving
Questions1. How do we know that the composition
of the atmosphere has changed in the past?
Keywords:
•Isotope Ratios
•Ice Cores
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
SummaryDriving
Questions2 Ignoring greenhouse gas emissions
what climate changes might we expect next?
Keywords:
•Milankovitch Theory
oEccentricity
oPrecession
oObliquity
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues Abrupt extinction due to climate change
PaleoclimatologyAbrupt climate change (circa 2200 BC)forced the abandonment of rain-fed settlements in agricultural plains of lower Mesopotamia.
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
PaleoclimatologyPeriod of drought between ~800 to 1000 A.D. probably contributed to collapse of Mayan civilization.
Climatology and Paleoclimatology
Paleoclimate
Summary
Climate
Issues
Paleoclimatology