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

Is Air Travel Safe?

Aviation expert says despite tragic losses of Malaysian Airlines flights 370 and 17, industry experienced lowest fatality rate in recorded history last year More

Multimedia 100 Days Later, Nigerian Girls Still Held

Activists holding rallies in Nigeria and several other countries to mark 100th day of captivity for more than 200 schoolgirls being held by Boko Haram More

Chocolate Too Bitter? Swap Sugar for Mushrooms

US food technology company develops fermentation process using mushrooms to reduce bitterness in cocoa beans, believes it will cut sugar content in candy More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
US Carriers Suspend Travel to Israeli
X
Carolyn Presutti
July 23, 2014 1:21 AM
The United States is prohibiting American carriers from flying to Israel's airport in Tel Aviv for 24 hours, because of rising violence between Israel and Hamas militants. The action was announced on Tuesday, after a rocket fired by Hamas militants in the Gaza Strip landed near the airport. As VOA's Carolyn Presutti tells us, international officials soon may have to determine which combat zones are too dangerous for commercial flights.
Video

Video US Carriers Suspend Travel to Israel

The United States is prohibiting American carriers from flying to Israel's airport in Tel Aviv for 24 hours, because of rising violence between Israel and Hamas militants. The action was announced on Tuesday, after a rocket fired by Hamas militants in the Gaza Strip landed near the airport. As VOA's Carolyn Presutti tells us, international officials soon may have to determine which combat zones are too dangerous for commercial flights.
Video

Video NASA Focuses on Earth-Like Planets

For decades, looking for life elsewhere in the universe meant listening for signals that could be from distant civilizations. But recent breakthroughs in space technology refocused some of that effort toward finding planets that may harbor life, even in its primitive form. VOA’s George Putic reports on a recent panel discussion at NASA’s headquarters, in Washington.
Video

Video IAEA: Iran Turns its Enriched Uranium Into Less Harmful Form

Iran has converted its stockpiles of enriched uranium into a less dangerous form that is more difficult to use for nuclear weapons, according to the United Nations’ Atomic Energy Agency. The move complies with an interim deal reached with Western powers on Iran's nuclear program last year, in exchange for easing of sanctions. Henry Ridgwell reports for VOA from London.
Video

Video Relic of Saint Draws Catholics Worried About Immigration Issue

A Roman Catholic saint who is a figure of devotion for those crossing the border into the United States is attracting believers concerned about the plight of undocumented immigrants. Mike O'Sullivan reports from Los Angeles, where a relic of Saint Toribio has drawn thousands to local churches.
Video

Video US Awards Medal of Honor for Heroics in Bloodiest of Afghan Battles

U.S. combat troops are withdrawing from Afghanistan, on pace to leave the country by the end of this year. But on Monday, U.S. President Barack Obama took time to honor a soldier whose actions while under fire in Afghanistan earned him the Medal of Honor. VOA's Jeff Seldin has more from the Pentagon.
Video

Video Ukraine Rebels Surrender MH17 Black Boxes

After days of negotiations, a senior separatist leader handed over two black boxes from an airliner downed over eastern Ukraine to Malaysian experts early Tuesday. While on Monday, the U.N. Security Council unanimously demanded that armed groups controlling the crash site allow safe and unrestricted access to the wreckage.
Video

Video In Cambodia, HIV Diagnosis Brings Deadly Shame

Although HIV/AIDS is now a treatable condition, a positive diagnosis is still a life altering experience. In Cambodia, people living with HIV are often disowned by friends, family and the community. This humiliation can be unbearable. We bring you one Cambodian woman’s struggle to overcome a life tragedy and her own HIV positive diagnosis.
Video

Video Nature of Space Exploration Enters New Age

Forty-five years ago this month, the first humans walked on the moon. It was during an era of the space race between the United States and the Soviet Union. World politics have changed since then and -- as Elizabeth Lee reports -- so has the nature of space exploration.

AppleAndroid