Summer has passed

Some facts for the autumnal equinox:

  • The Earth has seasons because it orbits the sun while tilted 23.44˚ off the vertical axis.
  • This tilt varies with time, following a 41,000 year cycle.
  • At the maximum, the tilt is 24.5˚. At the minimum, it is 22.1˚. When there is more tilt, the difference between summer and winter increases. When there is less tilt, the seasons are more similar.
  • Along with the changes in the shape of Earth’s orbit (eccentricity – 100,000 year cycle) and the way the planet wobbles around the pole (precession – 26,000 year cycle), axial tilt (obliquity) contributes to the Milankovitch cycles – one of the major long-term drivers of natural climate change.
  • To learn more, look up Dansgaard-Oeschger events and Heinrich events.

Disclaimer: Yes, orbital and solar variations affect the planet’s climate. That doesn’t mean human greenhouse gas emissions don’t, nor that they aren’t the primary cause of the climate change presently taking place!

Author: Milan

In the spring of 2005, I graduated from the University of British Columbia with a degree in International Relations and a general focus in the area of environmental politics. Between 2005 and 2007 I completed an M.Phil in IR at Wadham College, Oxford. I worked for five years for the Canadian federal government, including completing the Accelerated Economist Training Program, and then completed a PhD in Political Science at the University of Toronto in 2023.

2 thoughts on “Summer has passed”

  1. You sir are wrong and a fool! We have seasons because Persephone was kidnapped by Hades. That crime so disheartened Demeter that she refuses to make things fruitful for a span of months equal in number to the pomegranate pips her daughter consumed in the underworld.

    Obviously.

Leave a Reply

Your email address will not be published. Required fields are marked *