Indus valley civilization collapse, climate change and threats of global warming

# Science in the news

200 year long drought wiped out the Indus valley  

In a ground-breaking discovery led by an Indian-origin palaeoclimatologist  
(http://www.esc.cam.ac.uk/people/research-students/yama-dixit)

researchers have found that a 200-year-long monster drought nearly 4,200 years ago 

doomed the Indus Valley Civilization in present Pakistan and northwest India.

Gateway at harappa: Indus Valley civilization
Pics courtesy:http://www.crystalinks.com/induscivilization.html

"The Indus Valley was characterised by large, well-planned cities with advanced municipal sanitation systems and a script that has never been deciphered.

Indus Valley Seals
Pic courtesy:http://www.crystalinks.com/induscivilization.html

pic courtesy:http://gatescambridge.org/

our-scholars/Profile.aspx?

ScholarID=5469

But the Harappans seemed to slowly lose their urban cohesion, and their cities were gradually abandoned,' explained Yama Dixit, a palaeoclimatologist at University of Cambridge.(http://www.deccanherald.com/content/389730/200-year-long-drought-wiped.html)

Palaeoclimatological research

The team assigned ages to sediment layers using radiocarbon dating of organic matter.

In various layers, they collected the preserved shells of tiny lake snails which are made of a form of calcium carbonate called aragonite.

The team also looked at the oxygen in the argonite molecules, counting the ratio of the rare oxygen-18 isotope to the more prevalent oxygen-16.

During drought, oxygen-16, which is lighter than oxygen-18, evaporates faster so that the remaining water in the lake and, consequently, the snails' shells, become enriched with oxygen-18.

The team's reconstruction showed a spike in the relative amount of oxygen-18 between 4,200 and 4,000 years ago.

The data, published in the journal Geology1, suggests that the regular summer monsoons stopped for some 200 years.

According to Anil Gupta, director of the Wadia Institute of Himalayan Geology in Dehradun, this work fills a gap in the geographic record of ancient drought. (http://www.deccanherald.com/content/389730/200-year-long-drought-wiped.html)  

Reference link and abstract of Yama Dixit's research paper:

http://www.esc.cam.ac.uk/people/research-students/yama-dixit

The Bronze Age Harappan Civilization was one of the world’s earliest great urban civilizations and flourished from ~4600 BP to 3900 BP. The collapse of its integrated urban structure has prompted much speculation, including suggestions of climate and environmental change playing a role in their demise. Palaeoclimate proxy evidence indicates that the time of the Harappan Civilization was marked by variable monsoon strength, punctuated by episodes of aridity. A decrease in the strength of the South Asian monsoon at 4.2 ka BP has been linked by some to the termination of the urban phase of the Harappan Civilization. However, the link between climate change and Indus cultural transformation is equivocal, particularly because of a lack of well-dated paleoclimate records from the region occupied by the Indus Civilization.

For my PhD, I am reconstructing the Holocene palaeoclimate history using lacustrine sediments from three lakes lying across the precipitation gradient on the plains of NW India. This study will contribute to our understanding of the Holocene history of past environmental and climatic change in this region and assess possible climate-cultural connections.

I am funded by Gates Cambridge Trust and my PhD research is supervised by Prof. David Hodell.

Concern of the day

Climate impacts 'overwhelming' - UN

thankfully shared from a report by Matt McGrath for BBC    

http://www.bbc.com/news/science-environment-26810559?OCID=fbasia&ocid=socialflow_facebook

The impacts of global warming are likely to be "severe, pervasive and irreversible", a major report by the UN has warned.

"Nobody on this planet is going to be untouched by the impacts of climate change,'' IPCC chairman Rajendra Pachauri told journalists at a news conference in Yokohama.

"Now, ignorance is no longer a good excuse," Michel Jarraud, secretary-general of the World Meteorological Organization has said.

 

A kind of warning for Indian subcontinent !!

We may lose much more, if lesson not learn on time

Our greedy developmental desires have set a rapid rate of deforestation, hills are broken for granite and sand, pollution is already growing at steady speed. In addition to that India doesn't get polar streams due to high altitude tibetan plateu. Entire country depends on monsoon only. Are we moving towards a scary future for our coming generations due to climate change. We are at jet speed spoiling the nature and natural resources...What is the value of the money..when the land turns into Mars like. (rajk12345/http://www.deccanherald.com/content/389730/200-year-long-drought-wiped.html)

Saraswati by Raja Ravi Varma 

pic courtesy:http://en.wikipedia.org/wiki/Saraswati

Losing ground water resource could be deavastating

Like all rivers, it was fed from a glacier which went dry. Example Gangotri Glacier now has receded some 8Km all the way to GoMukh. 100yrs back Gangotri glacier was near where today Gangotri is. Also , Indus valley civlization and the word Harappa are modern concoted.

Its aptly called as Sarswati civilization. So what caused the glacier to melt down could the global warming (1) with deforestation due to war (Kurukshetra war which occured some 5134 yrs ago, from history we know after the war river Sarswati ran for some 800 yrs +) that took place in the vicinity. (Dr. B. M. Nandeeshaiah/http://www.deccanherald.com/content/389730/200-year-long-drought-wiped.html)

Exploring Lost Places: Indus Valley Civilization

The Indus Valley Civilization (IVC)  
was a Bronze Age civilization (3300–1300 BCE; mature period 2600–1900 BCE) located in the western region of South Asia, and spread over what are now Pakistan, northwest and western India, eastern Afghanistan, and southeastern Iran. Flourishing in the Indus River basin, the civilization extended east into the Ghaggar-Hakra River valley and the upper reaches Ganges-Yamuna Doab; it extended west to the Makran coast of Balochistan, north to northeastern Afghanistan and south to Daimabad in Maharashtra. The civilization was spread over some 1,260,000 km², making it the largest ancient civilization.

The Indus Valley is one of the world's earliest urban civilizations, along with its contemporaries, Mesopotamia and Ancient Egypt. At its peak, the Indus Civilization may have had a population of well over five million. Inhabitants of the ancient Indus river valley developed new techniques in handicraft (carnelian products, seal carving) and metallurgy (copper, bronze, lead, and tin). The civilization is noted for its cities built of brick, roadside drainage system, and multistoried houses.

Cities: A sophisticated and technologically advanced urban culture is evident in the Indus Valley Civilization making them the first urban centres in the region. The quality of municipal town planning suggests the knowledge of urban planning and efficient municipal governments which placed a high priority on hygiene, or, alternatively, accessibility to the means of religious ritual.

Trade through shallow harbors located at the estuaries of rivers : There was an extensive maritime trade network operating between the Harappan and Mesopotamian civilizations as early as the middle Harappan Phase, with much commerce being handled by "middlemen merchants from Dilmun" (modern Bahrain and Failaka located in the Persian Gulf). Such long-distance sea trade became feasible with the innovative development of plank-built watercraft, equipped with a single central mast supporting a sail of woven rushes or cloth.

Several coastal settlements like Sotkagen-dor (astride Dasht River, north of Jiwani), Sokhta Koh (astride Shadi River, north of Pasni), and Balakot (near Sonmiani) in Pakistan along with Lothal in India testify to their role as Harappan trading outposts. Shallow harbors located at the estuaries of rivers opening into the sea allowed brisk maritime trade with Mesopotamian cities.

The collapse of civilization: Around 1800 BCE, signs of a gradual decline began to emerge, and by around 1700 BCE, most of the cities were abandoned.

A possible natural reason for the IVC's decline is connected with climate change that is also signalled for the neighbouring areas of the Middle East: The Indus valley climate grew significantly cooler and drier from about 1800 BCE, linked to a general weakening of the monsoon at that time. Alternatively, a crucial factor may have been the disappearance of substantial portions of the Ghaggar Hakra river system. A tectonic event may have diverted the system's sources toward the Ganges Plain, though there is complete uncertainty about the date of this event, as most settlements inside Ghaggar-Hakra river beds have not yet been dated. 

The actual reason for decline might be any combination of these factors. New geological research is now being conducted by a group led by Peter Clift, from the University of Aberdeen, to investigate how the courses of rivers have changed in this region since 8000 years ago, to test whether climate or river reorganizations are responsible for the decline of the Harappan. A 2004 paper indicated that the isotopes of the Ghaggar-Hakra system do not come from the Himalayan glaciers, and were rain-fed instead, contradicting a Harappan time mighty "Sarasvati" river.
Urban civilization gradually moved to Gangetic plains: A research team led by the geologist Liviu Giosan of the Woods Hole Oceanographic Institution also concluded that climate change in form of the easterward migration of the monsoons led to the decline of the IVC. The team's findings were published in PNAS in May 2012. According to their theory, the slow eastward migration of the monsoons across Asia initially allowed the civilization to develop. The monsoon-supported farming led to large agricultural surpluses, which in turn supported the development of cities. The IVC residents did not develop irrigation capabilities, relying mainly on the seasonal monsoons. As the monsoons kept shifting eastward, the water supply for the agricultural activities dried up. The residents then migrated towards the Ganges basin in the east, where they established smaller villages and isolated farms. The small surplus produced in these small communities did not allow development of trade, and the cities died out.

Indra-the god of rains: 
Most loved god of most old book ( Rig Veda) of Indian civilization:
As we find that mountain, rains, rivers have altered the course of life and in turn the whole set of civilization in such a great way that such vast cities of metropolitan structure (like Mumbai, India of today) deserted their habitation for all, a setback to then urban life style, loss of trade resulting in the migration of rich urban population to Gangetic plains and rest of poor population receded to villages. The pattern in settlement of IVC and Gangetic plain region have no difference.
Indra, the god of rains and thunderstorm is most revered god in the Rig Veda seems very justified.

1. Indra: the king of gods in Rig Veda: Indra (Devanagari: इन्द्र) or Śakra is the leader of the Devas or gods and Lord of Svargalok or heaven in Hindu mythology. He is the God of war, the god of thunderstorms. His weapon is the bolt (vajra). Indra is one of the chief deities in the Rigveda. He is the twin brother of Agni and hence said to be born of Dyaus Pitar (Father Heaven) and Prithvi Matar (Mother Earth). He is also mentioned as an Aditya, a son of Aditi. His home is situated on Mount Meru.
2. Origins of Indra:  Aspects of Indra as a deity are cognate to other Indo-European gods; they are either thunder gods such as Thor, Perun, and Zeus, or gods of intoxicating drinks such as Dionysos. The name of Indra (Indara) is also mentioned among the gods of the Mitanni, a Hurrian speaking people who ruled northern Syria from ca.1500BC-1300BC .

Janda (1998:221) suggests that the Proto-Indo-European (or Graeco-Aryan) predecessor of Indra had the epithet *trigw-welumos "smasher of the enclosure" (of Vritra, Vala) and diye-snūtyos "impeller of streams" (the liberated rivers, corresponding to Vedic apam ajas "agitator of the waters"), which resulted in the Greek gods Triptolemos and Dionysos.

Vedic Indra corresponds to Verethragna of the Zoroastrian Avesta as the noun verethragna- corresponds to Vedic vrtrahan-, which is predominantly an epithet of Indra. The word vrtra-/verethra- means "obstacle". Thus, vrtrahan-/verethragna- is the "smiter of resistance". Vritra as such does not appear in either the Avesta or in 9th-12th century books of Zoroastrian tradition. Since the name 'Indra' appears in Zoroastrian texts as that of a demon opposing Truth (Vd. 10.9; Dk. 9.3; Gbd. 27.6, 34.27)!> Zoroastrian tradition has separated both aspects of Indra.
3. Indra's Bow: In Hindu mythology, the rainbow is called Indra's Bow (Sanskrit: indradhanushya इंद्रधनुष).
4. Status and function: In the Rig Veda, Indra is the king of the gods and ruler of the heavens. Indra is the god of thunder and rain and a great warrior, a symbol of courage and strength. He leads the Deva (the gods who form and maintain Heaven) and the elements, such as Agni (Fire), Varuna (Water) and Surya (Sun), and constantly wages war against the opponents of the gods, the demon-like Asuras. As the god of war, he is also regarded as one of the Guardians of the directions, representing the east. As the favourite 'national' god of the Vedic Indians, Indra has about 250 hymns dedicated to him in the Rigveda.
5. Indra, Anthropomorhism: Scholars differ about the phenomenon which Indra represents. According to Max Műller Indra is the sun-god dispelling nocturnal darkness and pouring floods of light. Roth holds the view that Indra is the god of thunderstorm. Benfey regards Indra as the god of rainy sky. Grassmann taken him as the god of bright sky. Myrintheus identifies Indra with Dyaus. According to E. D. Perry Indra is the same as Greek Zeus and the Italian Jupiter. Macdonell and Keith are of opinion that Indra represents thunderstorm which brings down rain to the earth. Hopkins is of opinion that Indra represents lightning itself. Yãska's own view, that Indra or Vãyu as the deity of middle region represents the lightning in conflict with the clouds, supports the view of Hopkins. Indra as a god of thunderstorm representing lightning could legitimately be accompanied with Rudra, Maruts and Saramã. Indra is said to have pierced the mountains. They are described to move hither and thither like spotted deer. The clouds flying in air are fancied as atmospheric mountains with wings. At the time of Indra,s birth cows bellow.. This bellowing of cows refers to the roaring of clouds when lightning flashes.

picture courtesy:National Geographic