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

Elusive Deal With Iran Could Yield Foreign Policy Legacy for Obama

A new Iranian leader -- and a strategic shift by the United States -- opens narrow window for nuclear agreement with Tehran More

Column: Saudi-Iran Meeting Could Boost Fight Against Islamic State

The fact that Iranians and Saudis are talking again does not guarantee a breakthrough, but it could make it easier to build a broad coalition against IS More

Thai Ruler Gives Top Cabinet Posts to Junta Inner Circle

Thailand's army chief has kept an iron grip on power as he extends the government, hand-picking an interim parliament that subsequently nominated him prime minister More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
West Africa Ebola Vaccine Trials Possible by Early 2015i
X
Carol Pearson
August 30, 2014 7:14 PM
A U.S. health agency is speeding up clinical trials of a possible vaccine against the deadly Ebola virus that so far has killed more than 1,500 people in West Africa. If successful, the next step would be a larger trial in countries where the outbreak is occurring. VOA's Carol Pearson has more.
Video

Video West Africa Ebola Vaccine Trials Possible by Early 2015

A U.S. health agency is speeding up clinical trials of a possible vaccine against the deadly Ebola virus that so far has killed more than 1,500 people in West Africa. If successful, the next step would be a larger trial in countries where the outbreak is occurring. VOA's Carol Pearson has more.
Video

Video Survivors Commemorate 70th Anniversary of Nazi Liquidation of Jewish Ghetto

When the German Nazi army occupied the Polish city of Lodz in 1939, it marked the beginning of a long nightmare for the Jewish community that once made up one third of the population. Roughly 200,000 people were forced into the Lodz Ghetto. Less than 7,000 survived. As VOA’s Kane Farabaugh reports, some survivors gathered in Chicago on the 70th anniversary of the liquidation of the Lodz Ghetto to remember those who suffered at the hands of the Nazi regime.
Video

Video Cost to Raise Child in US Continues to Rise

The cost of raising a child in the United States continues to rise. In its latest annual report, the U.S. Department of Agriculture says middle income families with a child born in 2013 can expect to spend more than $240,000 before that child turns 18. And sending that child to college more than doubles that amount. VOA’s Deborah Block visited with a couple with one child in Alexandria, Virginia, to learn if the report reflects their lifestyle.
Video

Video Chaotic Afghan Vote Recount Threatens Nation’s Future

Afghanistan’s troubled presidential election continues to be rocked by turmoil as an audit of the ballots drags on. The U.N. says the recount will not be completed before September 10. Observers say repeated disputes and delays are threatening the orderly transfer of power and could have dangerous consequences. VOA correspondent Meredith Buel reports.
Video

Video Ukraine Battles Pro-Russia Rebel Assault

After NATO concluded an emergency meeting to discuss the crisis in eastern Ukraine, the country is struggling to contain heavy fighting near the strategic port of Mariupol, on the Azov Sea. Separatist rebels are trying to capture the city, allegedly with Russian military help, and Ukraine's defense forces are digging in. VOA's Daniel Schearf spoke with analysts about what lies ahead for Ukraine.
Video

Video Growing Business Offers Paint with a Twist of Wine

Two New Orleans area women started a small business seven years ago with one thing in mind: to help their neighbors relieve the stress of coping with a hurricane's aftermath. Today their business, which pairs painting and a little bit of wine, has become one of the fastest growing franchises across the U.S. VOA’s June Soh met the entrepreneurs at their newest franchise location in the Washington suburbs.
Video

Video Ebola Vaccine Trials To Begin Next Week

The National Institutes of Health says it is launching early stage trials of a vaccine to prevent the Ebola virus, which has infected or killed thousands of people across West Africa. The World Health Organization says Ebola could infect more than 20,000 people across the region by the time the outbreak is over. The epidemic has health experts and governments scrambling to prevent more people from becoming infected. Zlatica Hoke has more.
Video

Video Asian Bacteria Threatens Florida Orange Trees

Florida's citrus fruit industry is facing a serious threat from a bacteria carried by the Asian insect called psyllid. The widespread infestation again highlights the danger of transferring non-native species to American soil. VOA’s George Putic reports.
Video

Video Aging Will Reduce Economic Growth Worldwide in Coming Decades

The world is getting older, fast. And as more people retire each year, fewer working-age people will be there to replace them. Bond rating agency Moody’s says that will lead to a decline in household savings; reducing global investments - which in turn, will lead to slower economic growth around the world. But experts say it’s not too late to mitigate the economic impact of the world’s aging populations. Mil Arcega has more.
Video

Video Is West Doing Enough to Tackle Islamic State?

U.S. President Barack Obama has ruled out sending ground troops to Iraq to fight militants of the so-called Islamic State, or ISIS, despite officials in Washington describing the extremist group as the biggest threat the United States has faced in years. Henry Ridgwell reports from London on the growing uncertainty over whether the West’s response to ISIS will be enough to defeat the terrorist threat.
Video

Video Coalition to Fight Islamic State Could Reward Assad

The United States along with European and Mideast allies are considering a broader assault against Islamic State fighters who have spread from Syria into Iraq and risk further destabilizing an already troubled region. But as VOA State Department Correspondent Scott Stearns reports, confronting those militants could end up helping the embattled Syrian President Bashar al-Assad.
Video

Video Made in America Socks Get Toehold in Online Fashion Market

Three young entrepreneurs are hoping to revolutionize the high-end sock industry by introducing all-American creations of their own. And they’re doing most of it the old-fashioned way. VOA’s Julie Taboh recently caught up with them to learn what goes into making their one-of-a-kind socks.
Video

Video Americans, Ex-Pats Send Relief Supplies to West Africa

Health organizations from around the world are sending supplies and specialists to the West African countries that are dealing with the worst Ebola outbreak in history. On a smaller scale, ordinary Americans and African expatriates living in the United States are doing the same. VOA's Carol Pearson reports.

AppleAndroid