The Earth’s orbit around the sun can have an impact on global warming and cooling. The Milankovitch cycles show the Earth’s orbital changes over time, which can affect the amount of solar radiation and thus, the temperature.
The Milankovitch Cycles: 3 Variations of Earth’s Orbit
The Milankovitch cycles, according to NASA, introduced the three variations of Earth’s orbit that affect how much insolation reaches the top of the atmosphere and where it reaches.
The three variations in Milankovitch cycles are:
- Eccentricity
- Obliquity
- Precession
Eccentricity
Eccentricity is the shape of the Earth’s orbit and measures the Earth’s orbit changes from a perfect circle. The Earth’s orbit is not perfectly circular due to the gravitational pull from the two largest planets in the solar system, Jupiter and Saturn, causing the orbit to be slightly elliptical. The more elliptic the Earth’s orbit is, up to 23% more insolation reaches Earth when we are closest to the Sun.
Obliquity
Obliquity is the angle at Earth’s axis of rotation is titled as the planet travels around the Sun. The axis tilt is why we have seasons on the planet. When Earth’s axis is at a greater tilt, the more extreme each season can become. Melting ice sheets and glaciers are great examples of how the axis’ tilt can affect the amount of solar radiation the Earth receives.
Think of it like this: When the Earth is tilted more towards the Sun during the summer, the more insolation that hemisphere will receive.
Precession
Precession, or axial precession, is where the tidal forces from the gravitational pull from the Moon and Sun cause the Earth to wobble as it rotates on its axis. Precession is why the seasons are different in the Northern and Southern Hemispheres. For example, the Southern Hemisphere receives more solar radiation, causing hotter summers. This contrasts with the Northern Hemisphere experiencing seasonal variations. Axial precession of the Earth has its own cycle as well, lasting about 25,771.5 years. We could these conditions flip, with the Northern Hemisphere experiencing more solar radiation and the Southern Hemisphere experiencing seasonal variations – in about 13,000 years.
Eccentricity, obliquity, and precession are all aspects of the planet’s trip around the sun that affect the climate. Earth’s orbit isn’t the leading factor in more extreme climate events, but it does shed a light on some perspectives that slight changes in the climate are natural.