< p > < span style="font-size:14px">During the twentieth century, the earth’,s  surface warmed by about 1.5 ^°F. There are a variety of potential causes for global climate change, including both natural and human-induced mechanisms. Science has made great strides recently in determining which potential causes are actually responsible for the climate change that occurred during the twentieth century, providing strong evidence that greenhouse gases released to atmosphere by human activities are one of the main causes of contemporary global warming. The paper deliberates to deal with some of the others as well.