General Introduction
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Chapter -1 General Introduction Contents 1.1 Introduction - 1 1.2 The Vedic Period (10,000-8,000 BP) - 3 1.3 The Ramayana Period (8,000-7,000 BP) - 4 1.4 The Mahabharata Period (7,000-6,000 BP) - 4 1.5 The Indus Valley Civilization (5,000-4000 BP) - 5 1.6 Period of Social Transformation through Religion - 6 1.7 Period of Compilation of Ancient Hindu Scriptures - 6 1.8 Post-Buddha Period - 7 1.9 The Little Ice Age (LIA) - 7 1.10 A Brief History of Raingauge - 8 1.11 Instrumental Temperature Variations - 10 Reference - 14 Figures - 18 Chapter I General Introduction CHAPTER -1 General Introduction 1.1 Introduction Understanding the science of climate change and impact of rising trend in global tropospheric temperature on environment, hydrometeorological services and society are important problems of contemporary research. Fluctuation in global temperature has been relatively less (15°C±1.5°C) during the past 10,000 years (Holocene or the whole recent) compared to the earlier period since the land- atmosphere-water came into existence 4.1 billion years ago when it ranged between 22°C and 11 °C. But the small variation in temperature during the Holocene period drastically affected the cultural evolution of the human society of the Indian subcontinent (Singh and Ranade 2009). Climate refers to a mean state of the atmosphere considering intrinsic dynamics characterized by interannual variation, seasonal cycle and diurnal cycle. Climate change is defined as a significant change in climatic conditions (radiation, temperature, pressure, wind, cloud and precipitation) during a specific period compared to the preceding period capable of causing considerable impact on the settled ecosystem (vigor, vitality and type of natural and man-made ecosystems). Like the Earth, the Earth's climate has a history extending over -4.5 billion years. Processes in the atmosphere, oceans, cryosphere (snow cover, sea ice, and continental ice sheets), biosphere, and lithosphere (such as plate tectonics and volcanic activity) and certain extraterrestrial factors (such as the Sun) have caused these changes of climate. Thus, duration of climate change varies drastically from one scientific discipline to another. The climate change is gradual rather than abrupt and relative rather than absolute. Short period climatic changes are useful to understand changes in weather pattern. A provisional time-scale to gauge climate change in different scientific disciplines is, geological -106 years, geophysical -105 years, anthropological -104 years, archaeological -103 years, historical ~102 years, climatological -30 years, (hydro) meteorological -10 years and media and press few hours to few days (Singh et al. 2010b). The numerical value of the time scale is not 1 Chapter I Geiwi'al Inti•oduction the sharp boundary rather than length of the window-width, which can move one or two steps on both sides. Climate change research requires borrowing knowledge from subjects like geography, geology, geophysics, meteorology, climatology, hydrology, atmospheric sciences, agriculture, oceanography, remote sensing and geographic information system (RS-GIS), palaeo-climatology, palaeo-hydrology, anthropology, mythology, archaeology, history, economics, politics, psychology, religion, philosophy, spirituality, literature and, indology, though the list is not exhaustive (Singh et al. 2010 a&b). An overview of the impact of climatic change on evolution of humans in the Rift Valley (eastern Africa) around 2.5 million years ago, evolution of human society over Indian subcontinent in the past 10,000 years and human activities across India in recent few decades and years is in order. Evolution of Humans: Humans and human society have evolved in the backdrop of climatic changes. The human society is destined to live with worries for the future security of food, clothing, shelter, health, education, employment, economy, environment, communication and transportation. In the tropics, climate change refers to extreme climatic fluctuations between availability and non-availability of water. Further, concern of human beings for water is wide-ranging: divine-philosophical, chemical-biological, spiritual-religious, climatic-cultural, scientific-engineering (computational) and services-society. Adequate fresh water availability is essential for spiritual growth of human beings and healthy physical-material human society. Drastic and complicated spatial and temporal changes are expected in the general atmosphere and an Asia-India monsoon circulation as well as the availability of fresh water across the globe during the global warming scenario with a warming at a faster rate over the southern hemisphere (SH) than that of the northern hemisphere (NH). During dry climate spirituality, religion, philosophy, literature, peace, mercy, compassion and charity dominate the psyche of the people, and during the wet climate economics, power, politics, trade, wealth, commerce, insanity, looting, corruption, invasion and war. The humans were evolved from the Great Apes (chimpanzees, gorillas and orangutans) due to occurrence of dry climate in the Rift Valley (East Africa) about 2.5 million years ago. During droughts, the Great Apes started walking by raising them on their two back legs in search of food. In due course, they could walk faster on two 2 Chapter I General Introduction legs and started migrating towards better habitation and food. Around 100,000 years before present, the modern looking man emerged in the Middle East. Besides hunting, the humans started collecting food grains from the wild. Down the line, the humans learnt the art of cultivating some wild plants to produce food grains, which marked the beginning of the Neolithic Culture, and a discovery in the human civilizing process. Earliest known sites of the Neolithic Culture are Levant (Jericho, Palestine) and Byblos (Lebanon) that go back to around 9,500BC to 9000BC, the 'Fertile Crescent' in the Middle East (semicircular area across northern part of the Syrian Desert and extending from the Nile Valley to the Tigris and Euphrates rivers) 9000 BC, the Mehrgarh Culture (Baluchistan, Pakistan) 7500 BC, the Pengtoushan Culture and the Peiligang Culture (East Asia) 7500BC to 5000BC and the Ganga plains (India) 7000 BC to 5000 BC. Evolution of Hitman Society in Indian Subcontinent: In the following, climatic changes over the past 10,000 years and cultural evolution of the Indian subcontinent are described (Archibald 2007; Dansgaard et al. 1969; Fagan 2009; Frawaley and Rajaram 2009; Radhakrislina 1999 a & b; Rigveda 1993; Saroj Bala 2003; Singh et al. 1974; Singh and Ranade 2009 and Tilak 1903). 1.2 The Vedic Period (10,000-8,000 BP) The first five mandalas (chapters) of the Rig Veda provide ample evidence that rivers flowed in northwestern India from snow-ice melt, and there was mention of clouds, rain, thunder and lightning in the remaining five mandalas. This type of climatic condition occurred prior to 8,000 BP that is during ending phase of the last glacial period and start of Holocene. The snow-ice melt-fed perennial Saraswati flowed from Shimla to Arabian Sea via Himachal Pradesh, Punjab-Haryana-Delhi, Rajasthan and Gujarat. At the time the humans started practicing agriculture, they had understanding that everything in existence was important to them. The people with spiritual knowledge enjoyed great respect in the society. The large masses opted for lifestyle conducive for spiritual knowledge; the guru-protege lineage, in which accumulated and new generated knowledge were described in refined language (Sanskrit Shlokas), and transferred orally from generation to generation. With this lifestyle, the human society lived in the Saraswati River basin for about 2,000 years (10,000-8,000 B.P.). Around 8,000 B.P., the snow-ice cover in lower-upper western 3 Chapter I General Introduction Himalaya exhausted due to warmer atmosphere (global annual surface air temperature {GASAT} > 15°C) and the Saraswati River desiccated to a dry channel. Sixteen shlokas in the Rig Veda provide vivid description of fluctuating behavior of the Vedic Saraswati: sometimes there were heavy floods, sometimes low flows, sometimes no flows and sometimes changes in its course. Further, freezing and melting of the Saraswati River also occurred during this period. 1.3 The Ramayana Period (8,000-7,000 BP) As the flow started diminishing in the Saraswati River, the people migrated towards east along the bank of the Ganges River and south (peninsula) while searching water bodies of fresh water e.g. rivers, lakes, streams etc. The GASAT was about 15°C, and the Asia-India monsoon was similar to present day - ample monsoon rainfall and moderate summer and winter seasons. Large masses of the people practiced agriculture. Recent archeological findings suggest that Neolithic Culture flourished in the Ganga plains during 9,000-7,000 BP, and there were cultivation of crops like rice, hulled barley, bread-wheat, dwarf-wheat, lentil, green-gram, grass- pea, field-pea, horse-gram, sesame, grape, common vetch and Job's tear (Pal 2008; Pokharia et al. 2009; Tewari et al. 2006). However, the lifestyle of the human society that evolved in the Indo-Gangetic Plains was different compared to that of the Vedic Period. Kishkindha Kanda of the Valmiki Ramayana in its 66 shlokas provides evidence that the Indian peninsula received ample rains when Indo-Gangetic Plains was relatively drier. Around 7,000 B.P., the GASAT became more than 15.5°C and there was a westward shift in 'heat low' (prime component of Asia-India Monsoon) from northwest India-Pakistan to Iran-Saudi Arabia and core rainfall activities from central India-and-Indo-Gangetic plains to northwestern India. The people started migrating towards west and the Ramayana Culture in the Indo-Gangetic plains started waning. 1.4 The Mahabharata Period (7,000-6,000 BP) During 7,000-6,000 BP, the NH temperature was higher than 16° C. The atmosphere was the hottest compared to other parts of the Holocene period and the summer monsoon was the wettest due to excessive heating of the dry and high lands of the southern and central Asia.