In 2007, the Intergovernmental Panel on Climate Change (IPCC), an international panel of experts established to provide decision-makers with an objective source of information about climate change, released its Fourth Assessment Report [PDF]. This report used stronger language than the previous three, ultimately concluding that, based on thousands of studies, "warming of the climate system is unequivocal." The report also stressed the need for immediate action to slow climate change. There is little doubt left within the scientific community that climate change is real, and there is an abundance of data to support both the causes and effects of the phenomenon. Some of the effects are already readily observable, such as melting ice caps in Antarctica and Greenland, record global temperatures, and rising sea levels.
Scientists are more certain than ever before that the recent climate change is a result of human activity. The IPCC report states that the increases in global average temperatures since the 1950s are very likely due to human actions. Should the increase in global temperatures continue unchecked, scientists predict severe consequences to the world's economy, environment, and people.