CLIMATE CHANGE AND THE THREAT THAT IT POSES TO HUMAN EXISTENCE IS A MAJOR CONCERN TODAY. EVEN THE YOUTH HAVE AN IMPORTANT ROLE TO PLAY TO SAVE PLANET EARTH R K PACHAURI There are many lessons in human history which provide adequate warning about the chaos and destruction that could take place if we remain guilty of myopic indifference to the progressive erosion and decline of nature's resources. Much has been written, for instance, about the Maya civilization, which flourished during 250-950 AD, but collapsed largely as a result of serious and prolonged drought. Even earlier, some 4,000 years ago a number of well-known Bronze Age cultures also crumbled extending from the Mediterranean to the Indus Valley, including the civilizations, which had blossomed in Mesopotamia. More recent examples of societies that collapsed or faced chaos on account of depletion or degradation of natural resources include the Khmer Empire in South East Asia, Eastern Island, and several others. Changes in climate have historically determined periods of peace as well as conflict. The Climate Change 2007: Synthesis report by IPCC gives enough evidence to show the changes in climate. Eleven of the last 12 years (1995-2006) rank among the 12 warmest years in the instrumental record of global surface temperature (since 1850). Not only this, the global sea level has risen since 1961 at an average rate of 1.8 [1.3 to 2.3] mm/yr and since 1993 at 3.1[2.4 to 3.8] mm/yr, with contributions from thermal expansion, melting glaciers and ice caps, and the polar ice sheets. Climate change will have several implications, as numerous adverse impacts are expected for some populations in terms of access to clean water, access to sufficient food, stable health conditions, ecosystem resources, security of settlements. By 2020, in some African countries, yields from rainfed agriculture could be reduced by up to 50%. Agricultural production, including access to food, in many African countries is projected to be severely compromised. Climate change is likely to lead to some irreversible impacts on biodiversity. There is medium confidence that approximately 20%-30% of species assessed so far are likely to be at increased risk of extinction if increases in global average warming exceed 1.5-2.5