# 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)
(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.
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| 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.
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| Indus Valley Seals Pic courtesy:http://www.crystalinks.com/induscivilization.html |
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| pic courtesy:http://gatescambridge.org/
our-scholars/Profile.aspx?
ScholarID=5469 |
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)
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:
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 for BBC
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 !!
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.  |
Saraswati by Raja Ravi Varma
pic courtesy:http://en.wikipedia.org/wiki/Saraswati |
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.
