Changes In The Earths Orbit example essay topic
353 words
"Identify and present evidence for three natural mechanisms of climate change, any of which might have caused all or part of the long-term global warming trend observed since the late 19th century". It is often assumed that the main reasons for an increase in global temperatures since the 19th century are due to the impact of man. However further scientific research has proven that this is not always the case and we often under-estimate the power of many natural processes. 1. Sun Activity. The sun is the main factor that increases or decreases global temperatures, as its' output and distance from the earth changes. Sunspots occur on the surface of the sun over an eleven year cycle, when the sun is brighter during periods of high activity. When there is greater sunspot activity it has been found that there is greater ozone formation. This transfers heat to the lower atmosphere, so increasing global temperatures. Changes in the earths orbit occur, because the earth moves in elliptical orbits. The orbit will have reversed in 10,000 years time, so between these periods it is likely that the earth will have passed closer to the sun, hence changing global temperatures. 2.
Ocean Circulation. The ocean currents re-distribute heat energy. Because of the earth's tilt, unequal concentrations of energy reach the poles. The Gulf Stream warms the North Atlantic, evaporation occurs, making the water denser, so it sinks taking carbon dioxide with it from the atmosphere.
This controls greenhouse gases concentrations, therefore greatly affecting the global climate. 3. Volcanic Activity. It is hypothesized that volcanic eruptions cause the earth to cool for up to several years, because large quantities of dust and gases are injected into the atmosphere, reflecting the incoming solar energy, and thus the energy to the earths's ur face by 5-10%. Throughout history man has had to adapt to cope with a climate that varies over time, and climatic change is not a new idea, it has occurred over the last millions of years.
Bibliography
. Internet resources: articles by Phillip Ball, and the BBC News website. Exploring Ocean Science, by Keith Stowe. Environmental Science for Environmental Management, edited by Timothy O'Riordan. Page 215. The Role of the Sun in Climate Change, by D. Hoyt.
