Climate Change - Milankovitch Theory - Eccentricity Cycle

Climate change due to variations in the earth's orbit - Milankovitch Theory

1) eccentricity cycle - the earth's orbit around the sun is elliptical.

• the shape of the ellipse (eccentricity) varies from less elliptical to more elliptical back to less elliptical and take about 100,000 years to complete this cycle.
• currently, we are in an orbit of low eccentricity (near circular).
  • review - when are we closest to the sun?
  • review - when are we furthest away from the sun?

• Data analysis for the last 800,000 years of deep-ocean sediments show that ice coverage is a maxima every 100,000 years
• this matches the Eccentricity cycle period