Milankovitch Theory: The Cause Of Climate Change

Milankovitch theory

There are several factors that affect/ cause climate change. It ranges from things such as natural variability e.g. latitude of a certain region and anthropogenic things such as change in concentration of carbon dioxide. It is also proven that the astronomical theory, Milankovitch theory is a great concept that describes climate change (Paillard, 2010:273). In this essay the concept of Milankovitch theory will be discussed in terms of the earth eccentricity, the obliquity of the ecliptic and the procession of the equinoxes. Secondly discussion on how to distinguish natural variability and anthropogenic climate change from each other will be discussed.

Eccentricity of the earth’s orbit

The earth rotates in an elliptical

This phenomenon is accountable for the difference between summer and winter (whether there will be a huge gap or not). If the tilt of the earth towards the sun is less there are a number of factors that are effected. Firstly the solar incoming radiation is evenly distributed between summer and winter. Secondly it contributes to the difference in radiation received at the equator and poles promoting the growth of ice sheets at the poles. As the radiation would be evenly distributed, if the tilt is less, it would cause warmer winter. In this winter there would be warmer air that contains moist which would contributes to the maintenance/ formation of ice sheet. In addition summer temperature would be cooler and this would be benefit to the poles as no ice melting would

The amounts of solar radiation reaching earth at different latitude caused by different angle is one of the example. At the equator the sun shines directly overhead at a 90 degree angle increasing radiation reaching the surface here. At the poles the radiation is spread over a large area in a slanted way decreasing amount of energy reaching the surface. Another scenario that can be looked at is the length of daylight hours. The longer the daylight hour the more radiation. By the tilt of the earth to 23.3 degrees the sun shines directly over the Tropic of Capricorn thus causing it to have maximum day (24 hour daylight). This is called the summer solstice and happens during time of 22-23 December. Over the tropic of Cancer there will be maximum night called winter solstice that occurs at the period of 20-21 July (Tyson & Preston-Whyte, 2014. The Weather and Climate of Southern Africa. 2nd ed. South Africa: Cape Town). Secondly the atmosphere contributes greatly to the amount of radiation. As radiation enters through the atmosphere in the stratosphere there is ozone. This ozone layer helps prevent some harmful incoming radiation from reaching the earth. The thickness of this layer varies from place to place (causes of this will be discussed in the anthropogenic