Global Warming Essay -- Environment Global Warming Climate Change

Global Warming For the last 20 years or so the subject of global warming has spawned heated debate among the world’s brightest minds. Its causes and effects, if either actually exists, have been hotly debated. The most popular hypothesis is called the greenhouse effect with the agreed upon cause being green house gasses. These gasses are all naturally occurring and include water vapor, methane, oxygen, and the now infamous carbon dioxide. Greenhouse gasses exist in the atmosphere and have an effect on our global weather. They trap radiated heat and prevent it from exiting our atmosphere. This supposedly increases global temperatures and is, or will, cause melting of the polar ice caps. This in turn is expected to raise sea level and cause global coastal flooding. A brief geology lesson The world we live on is at least 4.6 billion years old. In that time span it has undergone immense changes. At one time most of the land surface was connected. The continents separated and migrated to their present positions. The force behind this is called plate tectonics. The sea floor is still spreading today and is the driving force for all of the earthquakes and volcanic activity that we experience today. Convection currents created by the tremendous heat and pressure of the inner core move the plates. This core is undergoing massive thermonuclear reactions. The heat produced migrates outward and the currents it produces move the plates. This process also releases enormous amounts of carbon dioxide and water vapor. This has been taking place since the Earth was formed. We know from geologic record that there have been numerous greenhouse and icehouse ages. The question is, is the greenhouse state caused by greenhouse gasses? Probably not, at least not entirely. There are several other factors involved - the most significant being the Milankovitch cycles. These are three cycles that describe the motion of the Earth through space. The first involves the Earth’s orbit around the sun. The orbit is not perfectly round, but elliptical. This means that at one point the Earth is closer to the sun than at other times. This cycle takes about 100,000 years to complete. The second cycle involves the tilt of the Earth’s axis. The Earth’s axis is currently tilted about 23.5 degrees. But this tilt is not constant. Throughout a period of about 40,000 years the tilt changes a f... ...een showing a downward trend since their peak in 1940. Satellite readings continue to show a decrease in temperature. They recorded 1997 as the coolest year since this technology has been implemented. This imagery was also accurate enough to predict â€Å"that â€Å"La Nina† would predominate in 1998, lowering global temperatures significantly"2. That same year Moscow recorded its coldest December in a century3. Conclusion This great world of ours has been around for a long time – at least 4.6 billion years. During that time untold and unimaginable changes have taken place. Countless icehouse and greenhouse ages have come and gone. Continents have been created, destroyed, and migrated over and over again. Thousands, perhaps millions, of species have come and gone. All this, and more, without any influence from man. In geologic terms we have been on this Earth for a very, very short time. The Earth evolves on a time scale that we cannot comprehend. It has developed a balance, a system of checks and balances, which we have little or no control over. To think that we can alter a global climate that has been 4.6 billion years in the making merely shows just how much we have yet to learn.