Revealed: How climate change ended world’s first great civilisations

'Megacities' of the Indus Valley region of Pakistan and north-west India declined and never recovered because of a dramatic increase in drought conditions, according to new research

Archaeology Correspondent

The world’s first great civilisations appear to have collapsed because of an ancient episode of climate change – according to new research carried out by scientists and archaeologists.

Their investigation demonstrates that the Bronze Age 'megacities' of the Indus Valley region of Pakistan and north-west India declined during the 21st and 20th centuries BC and never recovered – because of a dramatic increase in drought conditions.

The research, carried out by the University of Cambridge and India’s Banaras Hindu University, reveals that a series of droughts lasting some 200 years hit the Indus Valley zone – and was probably responsible for the rapid decline of the great Bronze Age urban civilization of that region.

The findings correlate chronologically with drought evidence found over recent years by other scientists who have examined deposits from the bottom of the Arabian Sea and the Gulf of Oman as well as stalactites from caves in North east India and southern Arabia.

It’s now thought likely that the droughts at around that time were partly responsible for the collapse not only of the Indus Valley Civilisation, but also of the ancient Akkadian Empire, Old Kingdom Egypt and possibly Early Bronze Age civilizations in Greece.

“Our evidence suggests that it was the most intense period of drought – probably due to frequent monsoon failure –  in the 5000 year-long period we have examined,” said  University of Cambridge Palaeoclimate scientist Professor David Hodell.

The scientists studying the collapse of the Indus Valley Civilization obtained their new evidence from a dried-up lake bed near India’s capital New Delhi which is just 40 miles east of the eastern edge of the Indus Valley Civilisation.

They detected the climatic conditions by examining isotopic evidence from the shells of snails that had lived between 6500 years ago and 1500 years ago.

The isotopic values of the calcium carbonate in the snails’ shells reflected the isotopic value in the water in the lakes at the time they lived.

Because water with oxygen 16 isotopes evaporates more quickly than water with ‘heavier’ oxygen 18 isotopes, the scientists were able to measure changes in evaporation rates over time. This allowed them to identify the start and end of a previously unknown 200 year-long severe drought in the north-west India region which lasted from around 2100BC to approximately 1900 BC.

In that period, the Indus Valley 'megacities' – some with populations of up to 100,000 – rapidly declined. Populations shrank and the old urban civilisation, which had lasted 500 years, collapsed.

“Archaeologists are really in a unique position when investigating climate change in the past, because we hopefully get to see what people were doing in the ‘before, during and after’ phases. We therefore get an opportunity to investigate how ancient populations responded to climatic and environmental change. How did they cope with periods of water stress? Were their existing ways of life resilient? Were they forced to adapt in order to survive, and if so, precisely what did they do,” said University of Cambridge archaeologist,  Dr. Cameron Petrie.

“For the Indus populations, it looks as though living in large groups became untenable, and it was much more sustainable to live in smaller groups. This is of course a huge simplification of a complex process, but this transformation is the underlying dynamic.

“By investigating responses to environmental pressures and threats in the past, we can hopefully learn from the past to engage with the public, and the relevant governmental and administrative bodies to be more pro-active in issues such as the management and administration of water supply, the balance of urban and rural development, and even the importance of preserving cultural heritage in the future,” said Dr. Petrie.

The new research is reported in the journal Geology.

PROMOTED VIDEO
News
ebooksAn unforgettable anthology of contemporary reportage
News
Bourgogne wine maker Laboure-Roi vice president Thibault Garin (L) offers the company's 2013 Beaujolais Nouveau wine to the guest in the wine spa at the Hakone Yunessun spa resort facilities in Hakone town, Kanagawa prefecture, some 100-kilometre west of Tokyo
i100
Voices
Oscar Pistorius is led out of court in Pretoria. Pistorius received a five-year prison sentence for culpable homicide by judge Thokozile Masipais for the killing of his girlfriend Reeva Steenkamp
voicesThokozile Masipa simply had no choice but to jail the athlete
Arts and Entertainment
James Blunt's debut album Back to Bedlam shot him to fame in 2004
music

Singer says the track was 'force-fed down people's throats'

News
i100
Life and Style
The Tinder app has around 10 million users worldwide

techThe original free dating app will remain the same, developers say

Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

IT Project Manager

Competitive: Clearwater People Solutions Ltd: Our client based in Chelmsford a...

Business Intelligence Specialist - work from home

£40000 per annum: Ashdown Group: An established and growing IT Consultancy fir...

Business Intelligence Specialist - work from home

£40000 per annum: Ashdown Group: An established and growing IT Consultancy fir...

IT Manager

£40000 - £45000 per annum + pension, healthcare,25 days: Ashdown Group: An est...

Day In a Page

Two super-sized ships have cruised into British waters, but how big can these behemoths get?

Super-sized ships: How big can they get?

Two of the largest vessels in the world cruised into UK waters last week
British doctors on brink of 'cure' for paralysis with spinal cord treatment

British doctors on brink of cure for paralysis

Sufferers can now be offered the possibility of cure thanks to a revolutionary implant of regenerative cells
Let's talk about loss

We need to talk about loss

Secrecy and silence surround stillbirth
Will there be an all-female mission to Mars?

Will there be an all-female mission to Mars?

Women may be better suited to space travel than men are
Oscar Pistorius sentencing: The athlete's wealth and notoriety have provoked a long overdue debate on South African prisons

'They poured water on, then electrified me...'

If Oscar Pistorius is sent to jail, his experience will not be that of other inmates
James Wharton: The former Guard now fighting discrimination against gay soldiers

The former Guard now fighting discrimination against gay soldiers

Life after the Army has brought new battles for the LGBT activist James Wharton
Ebola in the US: Panic over the virus threatens to infect President Obama's midterms

Panic over Ebola threatens to infect the midterms

Just one person has died, yet November's elections may be affected by what Republicans call 'Obama's Katrina', says Rupert Cornwell
Premier League coaches join the RSC to swap the tricks of their trades

Darling, you were fabulous! But offside...

Premier League coaches are joining the RSC to learn acting skills, and in turn they will teach its actors to play football. Nick Clark finds out why
How to dress with authority: Kirsty Wark and Camila Batmanghelidjh discuss the changing role of fashion in women's workwear

How to dress with authority

Kirsty Wark and Camila Batmanghelidjh discuss the changing role of fashion in women's workwear
New book on Joy Division's Ian Curtis sheds new light on the life of the late singer

New book on Ian Curtis sheds fresh light on the life of the late singer

'Joy Division were making art... Ian was for real' says author Jon Savage
Sean Harris: A rare interview with British acting's secret weapon

Sean Harris: A rare interview with British acting's secret weapon

The Bafta-winner talks Hollywood, being branded a psycho, and how Barbra Streisand is his true inspiration
Tim Minchin, interview: The musician, comedian and world's favourite ginger is on scorching form

Tim Minchin interview

For a no-holds-barred comedian who is scathing about woolly thinking and oppressive religiosity, he is surprisingly gentle in person
Boris Johnson's boozing won't win the puritan vote

Boris's boozing won't win the puritan vote

Many of us Brits still disapprove of conspicuous consumption – it's the way we were raised, says DJ Taylor
Ash frontman Tim Wheeler reveals how he came to terms with his father's dementia

Tim Wheeler: Alzheimer's, memories and my dad

Wheeler's dad suffered from Alzheimer's for three years. When he died, there was only one way the Ash frontman knew how to respond: with a heartfelt solo album