Natural Climate Change

By Kenton Shepard 

Climate change is a natural process and over the course of earth's history, climate has changed on all time scales. The primary cause of climate change has been changes in the earth's energy (radiation) balance. The three fundamental causes for changes in the balance of radiation are...

1. Changes in the Earth’s Orbit

The Milankovitch cycles are changes in the earth’s orbit and tilt which have resulted in what we call the ice ages. The three cycles repeat every 23,000, 41,000 and 100,000 years.

Source

Precession is a 23,000-year cycle

Changes in Levels of Solar Radiation

The sun goes through a solar cycle which reoccurs approximately every 11 years. During this cycle, changes take place in the sun’s magnetic field, resulting in cold (sunspot) and hot (faculae) areas of the sun’s surface which affect the earth’s temperature.

2. Changes in the Amount of Reflected Solar Radiation

Changes in the fraction of solar radiation reflected (called the albedo) by clouds, aerosols (tiny airborne particles) and land features such as ice, snow and deserts.

3. Changes in Longwave Energy Radiation

The Greenhouse Effect can change the amounts of energy which are radiated back into space.