Global Warming

Global warming refers to a long-term increase in the Earth's surface temperature that results in large-scale changes in global climate, namely redistribution of climatic zones defined by temperature, precipitation, and associated adapted ecosystems. Global climate changes, and episodes of global warming, have occurred throughout geologic history as a result of natural variations in incoming solar radiation, atmospheric chemistry, and oceanic and atmospheric circulation. Anthropogenic, or human-caused, global warming and climate change are a potential outcome of human activities during the last 150 years. Scientific data show that atmospheric concentrations of carbon dioxide, methane, nitrous oxide, and man-made chemicals called halocarbons are increasing as a result of emissions associated with human activities, and models predict that this environmental change may lead to global warming.