News / Science & Technology

Study: Climate Change Sped Indus Empire's Collapse

A city-settlement of the the Indus Valley Civilization, ca. 2600-1500 BCE. (Comrogues, Creative Commons)
A city-settlement of the the Indus Valley Civilization, ca. 2600-1500 BCE. (Comrogues, Creative Commons)
Rosanne Skirble
Climate change may have hastened the end of the largest civilization in the ancient world, according to a study in the Proceedings of the National Academy of Sciences.

The Indus empire, larger than its contemporaries Egypt and Mesopotamia combined, once held 10 percent of the world’s population and spanned 1 million square kilometers across the plains of the Indus River, from the Arabian Sea to the Ganges, encompassing what is today Pakistan, eastern Afghanistan and northwest India.

Despite its great cities and trade routes, the Indus civilization disappeared some 3,000 years ago and was nearly forgotten until the 20th Century, when archaeologists began unearthing its lost treasures. 

Trenches reveal signs of how the landscape was shaped by rivers, wind and climate. (Peter D. Clift/University of Aberdeen)Trenches reveal signs of how the landscape was shaped by rivers, wind and climate. (Peter D. Clift/University of Aberdeen)
x
Trenches reveal signs of how the landscape was shaped by rivers, wind and climate. (Peter D. Clift/University of Aberdeen)
Trenches reveal signs of how the landscape was shaped by rivers, wind and climate. (Peter D. Clift/University of Aberdeen)
Unlike the Egyptians or the Mesopotamians, the Indus didn’t build large temples or pyramids. Lead author Liviu Giosan, a geologist at the Woods Hole Oceanographic Institution, says the Indus people were more interested in agriculture and trade

“They farmed all the Indus Basin," Giosan says. "They had an extremely developed network of roads. They had sea links with Mesopotamia. They built big cities, orderly cities, in a grid. They had plumbing that was never encountered after that until the Romans came.”  

Archeological ruins of the Indus people, also known as the Harappans, were discovered in the 1920s. Studies since then have described an urban culture with sophisticated construction, sanitation systems, arts and crafts, and writing still not deciphered.  

In their work, Giosan and his colleagues used satellite images and topographical data to construct a model of the landscape where the Indus developed 5,200 years ago, built their cities, and then slowly declined between 3,900 and 3,000 years ago. 

“We went and dug trenches, or took sediment cores, or drilled to collect samples of sediment, so that we could understand where they formed," Giosan says. "Were they formed by the river? Were they formed by the wind, and when [were] they formed?”

The digital maps from the satellite images and the sediment records taken together reveal how agriculture and settlement patterns changed as the climate changed. 

Researchers collect sample sediment cores to chronicle changes in the Indus landscape over time. (Peter D. Clift/University of Aberdeen)Researchers collect sample sediment cores to chronicle changes in the Indus landscape over time. (Peter D. Clift/University of Aberdeen)
x
Researchers collect sample sediment cores to chronicle changes in the Indus landscape over time. (Peter D. Clift/University of Aberdeen)
Researchers collect sample sediment cores to chronicle changes in the Indus landscape over time. (Peter D. Clift/University of Aberdeen)
Among the most striking features, which the authors describe for the first time, is a mounded plain of river sediment, 10-to-20 meters high, 100 kilometers wide and running almost 1,000 kilometers along the Indus River. Giosan says it is seen as a sign of stability of the landscape.

According to the research, monsoon rains allowed settlements to grow and farming and trade to prosper. But when the monsoons began to bring less rain, the Indus did not irrigate their crops. Instead, they migrated eastward settling in smaller communities supported by rain-fed farming and dwindling streams for 1,000 years before their culture died out.  

The Indus River today is the source of the largest irrigation system in the world. But that system depends on a stable climate. Giosan says today’s changing climate - and the potential for more intense floods, like those that inundated Pakistan in 2010, could put millions of lives at risk.

“Then we have a problem. The entire Indus system, with its dams and canals for irrigation, is obsolete. It cannot function in that kind of climate. It is kind of a reversal to earlier types of climates when the river was wild. And we have to rethink that kind of development in the region.”

Giosan notes that people living there today cannot move across borders as easily as the Indus did so long ago, when the monsoons began to weaken. Giosan says the study provides a lesson from the past: that today’s mighty civilizations - whose industrial activities have sped the pace of climate change - must act to slow it or face the consequences.

You May Like

Lesotho Faces New Round of Violence, Political Crisis

Brutal killing of military officer has sent former leaders back into S. Africa where they're watching anxiously as regional officials head in to try to restore peace More

Video US Diplomat Expects Adoption of Bosnian Massacre Anniversary Resolution

Samantha Power says there's broad consensus about killings in Bosnia's war, but Russia calls resolution 'divisive,' backs UN countermeasure More

America's Most Exotic Presidential Pets

From alligators to bears, the White House has been home to some unusual presidential pets over the years More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Making Music, Fleeing Bombs: New Film on Sudan’s Internal Refugeesi
X
Carolyn Weaver
July 06, 2015 6:47 PM
In 2012, Sudanese filmmaker Hajooj Kuka went to make a documentary among civil war refugees in Sudan’s Blue Nile and Nuba Mountains region. What he found surprised him: music was helping to save people from bombing raids by their own government. VOA’s Carolyn Weaver has more.
Video

Video Making Music, Fleeing Bombs: New Film on Sudan’s Internal Refugees

In 2012, Sudanese filmmaker Hajooj Kuka went to make a documentary among civil war refugees in Sudan’s Blue Nile and Nuba Mountains region. What he found surprised him: music was helping to save people from bombing raids by their own government. VOA’s Carolyn Weaver has more.
Video

Video Rice Farmers Frustrated As Drought Grips Thailand

A severe drought in Thailand is limiting the growing season of the country’s important rice crop. Farmers are blaming the government for not doing more to protect a key export. Steve Sandford reports from Chiang Mai, Thailand.
Video

Video 'From This Day Forward' Reveals Difficult Journey of Transgender Parent

In her documentary, "From This Day Forward", filmmaker Sharon Shattuck reveals the personal journey of her transgender father, as he told his family that he always felt he was a woman inside and decided to live as one. VOA’s Penelope Poulou has more.
Video

Video Floodwaters Threaten Iconic American Home

The Farnsworth House in the Midwest State of Illinois is one of the most iconic homes in America. Thousands of tourists visit the site every year. Its location near a river inspired the design of the house, but, as VOA’s Kane Farabaugh reports, that very location is now threatening the existence of this National Historic Landmark.
Video

Video Olympics Construction Scars Sacred Korean Mountain

Environmentalists in South Korea are protesting a Winter Olympics construction project to build a ski slope through a 500-year-old protected forest. Brian Padden reports that although there is strong national support for hosting the 2018 Pyeongchang Winter Olympics, there are growing public concerns over the costs and possible ecological damage at the revered mountain.
Video

Video Xenophobia Victims in South Africa Flee Violence, Then Return

Many Malawians fled South Africa early this year after xenophobic attacks on African immigrants. But many quickly found life was no better at home and have returned to South Africa – often illegally and without jobs, and facing the tough task of having to start over. Lameck Masina and Anita Powell file from Johannesburg.
Video

Video Family of American Marine Calls for Release From Iranian Prison

As the crowd of journalists covering the Iran talks swells, so too do the opportunities for media coverage.  Hoping to catch the attention of high-level diplomats, the family of American-Iranian marine Amir Hekmati is in Vienna, pleading for his release from an Iranian prison after nearly 4 years.  VOA’s Heather Murdock reports from Vienna.
Video

Video UK Holds Terror Drill as MPs Mull Tunisia Response

After pledging a tough response to last Friday’s terror attack in Tunisia, which came just days before the 10th anniversary of the bomb attacks on London’s transport network, British security services are shifting their focus to overseas counter-terror operations. VOA's Henry Ridgwell has more.
Video

Video Obama on Cuba: This is What Change Looks Like

President Barack Obama says the United States will soon reopen its embassy in Cuba for the first time since 1961, ending a half-century of isolation. VOA White House correspondent Luis Ramirez reports.
Video

Video Hate Groups Spread Influence Via Internet

Hate groups of various kinds are using the Internet for propaganda and recruitment, and a Jewish human rights organization that monitors these groups, the Simon Wiesenthal Center, says their influence is growing. The messages are different, but the calls to hatred or violence are similar. VOA's Mike O’Sullivan reports.
Video

Video Blind Somali Journalist Defies Odds in Mogadishu

Despite improving security in the last few years, Somalia remains one of the most dangerous countries to be a journalist – even more so for someone who cannot see. Abdulaziz Billow has the story of journalist Abdifatah Hassan Kalgacal, who has been reporting from the Somali capital for the last decade despite being blind.
Video

Video Rabbi Hits Road to Heal Jewish-Muslim Relations in France

France is on high alert after last week's terrorist attack near the city Lyon, just six months after deadly Paris shootings. The attack have added new tensions to relations between French Jews and Muslims. France’s Jewish and Muslim communities also share a common heritage, though, and as far as one French rabbi is concerned, they are destined to be friends. From the Paris suburb of La Courneuve, Lisa Bryant reports about Rabbi Michel Serfaty and his friendship bus.

VOA Blogs