Earth's climate varies even without human influence but the acceleration in the changing pattern with cause and effect by/to the civilisation is a matter of concern to scientists. These patterns are lessons to understand future trends and ways and means for mitigation. The extreme weather events in almost every region of the globe involving excessive loss of human life and property are causing anxiety in society and posing challenges before scientists and planners. Cyclical variations in the Earth's climate occur at multiple time scales, from years to decades, centuries, and millennia. Cycles at each scale are caused by a variety of physical mechanisms. In the last 65 Ma only, there have been several cycles of glacial advances and retreat, with the abrupt end of the last ice age about 11,700 years ago marking the beginning of the modern climate era and human civilization. A multidisciplinary approach in studying the Earth's changing climate will provide a holistic view and guide us in future planning and programming.

This open access book discusses the impact of human-induced global climate change on the regional climate and monsoons of the Indian subcontinent, adjoining Indian Ocean and the Himalayas. It documents the regional climate change projections based on the climate models used in the IPCC Fifth Assessment Report (AR5) and climate change modeling studies using the IITM Earth System Model (ESM) and CORDEX South Asia datasets. The IPCC assessment reports, published every 6-7 years, constitute important reference materials for major policy decisions on climate change, adaptation, and mitigation. While the IPCC assessment reports largely provide a global perspective on climate change, the focus on regional climate change aspects is considerably limited. The effects of climate change over the Indian subcontinent involve complex physical processes on different space and time scales, especially given that the mean climate of this region is generally shaped by the Indian monsoon and the unique high-elevation geographical features such as the Himalayas, the Western Ghats, the Tibetan Plateau and the adjoining Indian Ocean, Arabian Sea, and Bay of Bengal. This book also presents policy relevant information based on robust scientific analysis and assessments of the observed and projected future climate change over the Indian region.