why should a geologist be studying climate?. what defines intervals on geologic timescale?
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Why should a geologist be studying climate?
What defines
INTERVALS
on geologictimescale?
What defines
BOUNDARIES
on geologictimescale?
What causes
ALL
mass extinctionevents?
CLIMATECHANGE
is responsiblefor the
organizationof the
geologictimescale
What are the (non-human) drivers of climate change?
What do thesestriations
result from?
Would glacial striations form in an environment like this?
Would glacial striations form in an environment like this?
Would glacial striations form in an environment like this?
Would glacial striations form in an environment like this?
Glacial remnantsin Africa are
explained by:
1) plate tectonics
Where do you find palm fronds today?
Fossil palm frond
Where do you find palm fronds today?
HawaiiHawaii
Where do you find palm fronds today?
BahamasBahamas
Where do you find palm fronds today?
Wyoming?Wyoming?
Where would you expect to find alligators today?
Where would you expect to find alligators today?
EvergladesEverglades
Where would you expect to find alligators today?
ChinaChina
Where would you expect to find alligators today?
Ellesmere Island?Ellesmere Island?
Alligator fossils found on Ellesmere Island78° North(north of
Greenland)54.8-33.7 Mya
Eocene
Ellesmere Island?Ellesmere Island?
Fossil palm fronds from Eocene(54.8-33.7 Mya) in Wyoming
Did plate tectonics cause this?Did plate tectonics cause this?
Have the positionsof Wyoming
and Ellesmerechanged much
over the last40 Mya?
Fossil palm fronds from Eocene(54.8-33.7 Mya) in Wyoming
NOTNOT caused by plate tectonics caused by plate tectonics
What was goingon here to change
global temperature?
Could wehave alligators
in the Arcticagain?
What else besides plate tectonics can cause climatechanges over long timescales?
2) Solar ForcingVariability
What causes the“eccentricity” ofEarth’s orbit
Gravitational interactions with the orbits of Jupiter and Saturn
What is the period of Earth’s eccentricity?
What is the period of Earth’s eccentricity?
What familiar climatephenomenon doesEarth’s “obliquity”cause?
Seasonality results from Earth’s obliquity
What is the period of Earth’s obliquity?
What is the period of Earth’s obliquity?
“Precession” of the equinoxes occurs due to tidal forcesfrom Sun and Moon
What is the period of Earth’s precession?
What is the period of Earth’s precession?
Combined solar forcing is known as “Milankovitch cycles”1920
Deep sea sediments record Milankovitch cycles over 500 Kya
Milankovitch cycles influence glacial cycles
How have glacial cycles changed over last 1000 Kya?
What else besides:
1) plate tectonics2) orbital changes
3) …?
can cause natural climate changes?
3) Variations in solar intensity…sunpot activity
NATURAL causes of global climate change:
1) plate tectonics2) orbital changes3) solar intensity
Earth’s climate system has great complexity
Earth’s ClimateComponents Simplified
5-partsystem
Earth’s Climate Components – Simplified
Cause and Effect~
“Forcing and Response”
1
2
3
Earth’s Climate Components – The Human Factor
1
2
3
4
Forcing:Factors that driveor cause change.
Forcing:Factors that driveor cause change.
Response:A system reactingto a change in forcing.
Forcing:Factors that driveor cause change.
Response:A system reactingto a change in forcing.
Lag Time:The time it takesa system to reactcompletely to a change in forcing.
Speed of Forcing Speed of Response
How quickly doesclimate react?
Speed of Forcing Speed of Response
100’s of millions of yrs
40,000-100,000 yrs
10,000s of yrs
Decades to CenturiesDecades to Centuries
Hours to Weeks
Hours to 10,000 yrs
Hours to Centuries
Days to 1,500 yrs
Hours to Months
??????????????????
Forcing Response
100’s of millions of yrs
40,000-100,000 yrs
10,000s of yrs
Decades to CenturiesDecades to Centuries
Hours to Weeks
Hours to 10,000 yrs
Hours to Centuries
Days to 1,500 yrs
Hours to Months
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