Class Notes (836,269)
Canada (509,735)
EARTHSC 1G03 (139)
Lecture 39

EARTHSC 1G03 Lecture 39: EARTHSC 1G03 - Lecture 39 (Global Change)
Premium

3 Pages
59 Views
Unlock Document

Department
Earth Sciences
Course
EARTHSC 1G03
Professor
Maureen Padden
Semester
Fall

Description
EARTHSC 1G03 Lecture 39: Global Change Variation in Global Geometry – Milankovich Theory 1. Eccentricity of Orbit o Periodically, Earth orbit goes from circular to elliptical on a 100 000 year cycle. o At high eccentricity, Earth can be periodically far away from the sun. o The colder seasons would allow ice to form, leading to cycle of glaciation. 2. Tilt of Earth Axis o The angle of tilt varies from 25.5º to 24.5º on a 41 000 year cycle. o At small angles of tilt, less sunlight reaches poles in summer • This could lead to persistence of winter ice through the summer 3. Precession of Wobble of Axis o Precession, or “wobbling” or Earth axis is on a 23 000 year cycle o Affects sunlight input Overall Change in Solar Input ➢ Periodically, precession, tilt, and eccentricity reinforce each other, leading to cyclic variation in heat input from the sun. ➢ Low periods correspond to glaciations. Peaks in cycles are about 100 000 years. Long-term Changes vs. Short-term Changes ➢ Long-term Changes o Ice ages happen throughout Earth’s history, but are rare o Triggers: ▪ Continent over poles ▪ Continent over hot spots, rise in elevation • Higher altitude = colder temperature ▪ Slower mid-ocean ridge spreading – more space in ocean, fewer shallo
More Less

Related notes for EARTHSC 1G03

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit