Realising the importance of climate change and its serious consequence to the society, the World Meteorological Organisation (WMO) and the United Nations Environment Program (UNEP) have jointly established the Intergovernmental Panel on Climate Change (IPCC) with the objective of accessing the available information concerning climate change and advising mitigation strategies to the Conference of the Parties (COP) and the United Nations Framework Convention on Climate Change (UNFCCC). Since 1990, the IPCC, with the help of numerous scientists from all over the world, has produced a number of reports on assessment, scientific and technical aspects, methodologies for mitigation, and so on. These reports have been based on periodic assessment, with the incorporation of new results that are available at the time of preparation of the reports. Thus, IPCC reports are widely accepted as reference material in the field of climate change science.

Based on the Third Assessment Report of IPCC (2001), additional observations project a world that is definitely warming. This report details an increase in the global surface temperature, a decrease in snow cover and ice extent, a rise of the global mean sea level, and some other important aspects of global climate change. The salient features indicating the overall warming of the globe are given here. It is important to note that the changes mentioned here are those due to natural variability, as well as human induced changes. It is difficult to separate and quantify human induced changes from those of natural variability.