Global warming could possibly be one of the most disastrous geohazards to affect Earth. Due to many factors, the average surface temperature on Earth is rising relatively rapidly. A rise in the average temperature could have profound consequences for living organisms now and in the future. Because a global rise in temperature could impact humans negatively in a variety of ways, global warming is a geohazard. Additionally, the effects of global warming have been accelerated by human activity. When systems theory is applied to the Earth, we find that changing even the smallest components of the atmosphere can create major changes.

There are many ways the Earth's temperature can rise. The Milankovitch cycle, plate tectonics, volcanic expulsions, meteors, the thermohaline cycle, sunlight, and pollution can all change the Earth's surface temperature.

The Milankovitch cycle is based on three factors that concern the Earth's position with respect to the sun (www.studyworksonline.com). The first factor is the shape of the Earth's orbit around the sun. This orbit "changes from more circular to more elliptical on a cycle of about 90,000 to 100,000 years" (www.studyworksonline.com). The Earth receives more solar radiation differential as the orbit becomes more elliptical, which leads to a larger yearly variation in weather. Currently we are in a more circular orbit, with a lesser degree of solar radiation differential.

The second Milankovitch factor is the "angle of the Earth's axis of rotation to the plane in which the planet orbits" (www.studyworksonline.com). This angle changes over a period of 41,000 years. Because the angle of the Earth's axis of rotation determines the four seasons, a smaller angle results in less defined seasons whereas a greater angle gives more intense seasons. We currently have an angle that is slightly greater than the middle. Thus, we must be somewhere near the middle of this 41,000 year cycle, and have slightly more pronounced seasons than average.
The third Milankovitch factor is the wobble of the Earth's axis. This wobble currently aims at the North Star, and will aim at the star Vega in about 12,000 years (www.studyworksonline.com). When the wobble points at Vega, the Earth will have much colder winters and much warmer summers. Eventually, in about 27,000 years the wobble will have returned to the North Star (www.studyworksonline.com).

Plate tectonics can alter surface temperature distribution, and do

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