At first glance the essay topic on global warming seemed simple. After researching many sites, such as the National Aeronautics and Space Administration (NASA), university studies, Intergovernmental Panel on Climate Change (IPCC) studies, International Non-Governmental Panel on Climate Change (NIPCC), and more, global warming it's very complicated. It depends on many factors, solar activity, deforestation, increased carbon dioxide from forest floors, obliquity (change in the tilt of the Earth's axis), volcanic eruptions, water vapor, use of fossil fuels, methane gases, cloud cover and other factors. There are many effects on global temperature, two of the main methods used to study this topic are global climate models (GCMs) and observational studies conducted around the world. Most scientific studies indicate that the main cause of global warming is increasing levels of carbon dioxide in the atmosphere. Some research shows that natural events are the main source of global warming. This essay will argue that carbon dioxide released into the atmosphere by human-caused actions is the primary reason for global temperature changes, secondarily, they are natural events. Some believe that carbon dioxide in the atmosphere causes a warming effect on the atmosphere. This carbon dioxide, as most studies have shown, has contributed to the increase in global temperature. There has been a lot of research to explain this. One of the best ways to study global warming is with computer models. Computer models use mathematical equations in a computer program that describe how atmospheric temperature, air pressure, water, ice,… Change-IPCC>.Spencer, Roy. nd http://www.drroyspencer.com/global-warming-natural-or-manmade/ Web. 20 November 2013. Intergovernmental Panel on Climate Change. Press Office, “The human influence on the climate is clear”. Press release. 27 September 2013. Web. 20 November 2013. http://www.climate2013.org/images/uploads/WGI-AR5_SPMPressRelease.pdf European Geosciences Union (EGU). "Oldest ice core: discovery of a 1.5-million-year record of Earth's climate." ScienceDaily, 5 November 2013. Web. 29 November 2013 http://www.sciencedaily.com/releases/2013/11/131105081228.htmClimate Science Research. “Once again quantifying the scientific consensus on human-caused global warming.” Climate science research. May 22, 2013. Web November 20, 2013. http://www.climatesciencewatch.org/2013/05/22/quantifying-scientific-consensus-on-global-warming/