2. What are the
Milankovitch
Cycles?
• An explanation for the cyclical ice ages based on
changes in Earth’s orbit, angle of tilt on its axis and
direction of tilt
3. The effect of
the changing
eccentricity
of Earth’s
orbit:
• If the eccentricity were to increase, the closest point to
the sun would have increased insolation, the farthest
point would have decreased insolation potentially
flipping the seasons
• Cycle Length: 100,000 years
4. What is the
effect of
changing the
angle of tilt
of the Earth?
• Obliquity – refers to the angle of tilt of the Earth’s axis;
currently at 23.5 degrees but fluctuates between 22.1-
24.5 degrees; the larger the angle of tilt the more
variance in seasons
• Cycle Length: 40,000 years
5. What is the
effect of
changing the
direction of
the angle of
tilt of the
Earth?
• Precession – the Earth wobbles like a top; the direction
of tilt slowly reverses over time
• Cycle Length: 19,000-24,000 years
