Transcript Causations of Climate Change

Causations of Climate Change
Causations of Climate Change
1.
2.
3.
4.
5.
Solar Activity
Plate Tectonics
Milankovitch Cycles
Ocean Circulation (will cover this next class)
Volcanic Eruptions
Solar Activity
• Amount of solar activity varies
• Increase in Sunspots=warmer in Europe and
N. America
• Less Sunspots=cooler periods
• Process is not really understood and is still
being investigated
Sunspots
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Plate Tectonics
Pangaea: Continental or
Maritime climate?
When continents are
close to poles there is
more ice
accumulation-why?
(albedo,global temps
drop)
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Volcanic Eruptions
• Volcanic ash, dust, sulphuric acid
droplets reflect sunlight increasing
albedo and decreasing temperature
short term
• More greenhouse gasses emitted
increase temperature longer term.
Volcanic Eruptions
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•
Mount Pinatubo cooled global temperatures by 5°C for a year. And
then temperatures steadily increased in the decades that followed.
What would cause this to happen?
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1. Orbit changes from circular to more elliptical on a 90-100 thousand year
cycle-elliptical has greater difference in amount of solar radiation
during winter/summer
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2.Planet wobbles on its axis of rotation
Currently northern hemisphere points towards
sun when earth is closest to sun (warmer
summer colder winter)
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3. Planet tilts on axis. Ranges from 22.1 ° to
24.5°. Smaller the angle the lesser the
difference between summer and winter.
Practice Questions
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1.
Current data depicts some correlation between
Milankovitch cycles and ice ages. Explain the most
likely scenario in which these cycles could result in
an ice age. Pick one of the cycles to explain
reasoning.