What causes Global Warming

Global Warming has alot to do with the change in our climate. The Earth's climate changes in response to external forcing, including variations in its orbit around the sun, volcanic eruptions, and atmospheric greenhouse gas concentrations (http://en.wikipedia.org/wiki/Global_Warming). The detailed causes of the recent warming remain an active field of research, but the scientific consensus identifies elevated levels of greenhouse gases due to human activity as the main influence (http://en.wikipedia.org/wiki/Global_Warming). This attribution is clearest for the most recent 50 years, for which the most detailed data are available (http://en.wikipedia.org/wiki/Global_Warming). In contrast to the scientific consensus that recent warming is mainly attributable to elevated levels of greenhouse gases, other hypotheses have been suggested to explain the observed increase in mean global temperature (http://en.wikipedia.org/wiki/Global_Warming). One such hypothesis proposes that warming may be the result of variations in solar activity (http://en.wikipedia.org/wiki/Global_Warming).