The earliest civilizations in history were the Sumerians in Mesopotamia, the ancient Egyptians and the Indus Civilization in Pakistan and India. Quite a lot is known about the first two, but the Indus Civilization is still a mystery. Their writing remains undeciphered so we do not know much about their history. We can’t even be certain of their ethnicity although it is very likely they were the ancestors of the Dravidian Indians. This civilization flourished for centuries but then collapsed quite suddenly from 1800-1700 BC. Evidently most of the inhabitants of the cities migrated eastwards. The cause of this collapse is unknown but this article in Yahoo news indicates that archeologists and historians are finding some answers.
The mysterious fall of the largest of the world’s earliest urban civilizations nearly 4,000 years ago in what is now India, Pakistan, Nepal and Bangladesh now appears to have a key culprit — ancient climate change, researchers say.
Ancient Egypt and Mesopotamia may be the best known of the first great urban cultures, but the largest was the Indus or Harappan civilization. This culture once extended over more than 386,000 square miles (1 million square kilometers) across the plains of the Indus River from the Arabian Sea to the Ganges, and at its peak may have accounted for 10 percent of the world population. The civilization developed about 5,200 years ago, and slowly disintegrated between 3,900 and 3,000 years ago — populations largely abandoned cities, migrating toward the east.
“Antiquity knew about Egypt and Mesopotamia, but the Indus civilization, which was bigger than these two, was completely forgotten until the 1920s,” said researcher Liviu Giosan, a geologist at Woods Hole Oceanographic Institution in Massachusetts. “There are still many things we don’t know about them.”
Nearly a century ago, researchers began discovering numerous remains of Harappan settlements along the Indus River and its tributaries, as well as in a vast desert region at the border of India and Pakistan. Evidence was uncovered for sophisticated cities, sea links with Mesopotamia, internal trade routes, arts and crafts, and as-yet undeciphered writing.
“They had cities ordered into grids, with exquisite plumbing, which was not encountered again until the Romans,” Giosan told LiveScience. “They seem to have been a more democratic society than Mesopotamia and Egypt — no large structures were built for important personalitiess like kings or pharaohs.”
My high school history textbook theorized that the people of Harappa and Mohenjo-Daro had a “Bronze-Age totalitarian” system of government because the cities and buildings were so similar to each other. It seems the authors were wrong.
The researchers’ conclusion is that the Indus Valley Civilization collapsed because of changing climates. If I am not mistaken, about this same time period, or somewhat earlier, the Sahara Desert was also becoming drier.
Some had suggested that the Harappan heartland received its waters from a large glacier-fed Himalayan river, thought by some to be the Sarasvati, a sacred river of Hindu mythology. However, the researchers found that only rivers fed by monsoon rains flowed through the region.
Previous studies suggest the Ghaggar, an intermittent river that flows only during strong monsoons, may best approximate the location of the Sarasvati. Archaeological evidence suggested the river, which dissipates into the desert along the dried course of Hakra valley, was home to intensive settlement during Harappan times.
“We think we settled a long controversy about the mythic Sarasvati River,” Giosan said.
Initially, the monsoon-drenched rivers the researchers identified were prone to devastating floods. Over time, monsoons weakened, enabling agriculture and civilization to flourish along flood-fed riverbanks for nearly 2,000 years.
I guess they should have paid more attention to their carbon footprint. Actually, the cause of the changing climate was entirely natural.
“The insolation — the solar energy received by the Earth from the sun — varies in cycles, which can impact monsoons,” Giosan said. “In the last 10,000 years, the Northern Hemisphere had the highest insolation from 7,000 to 5,000 years ago, and since then insolation there decreased. All climate on Earth is driven by the sun, and so the monsoons were affected by the lower insolation, decreasing in force. This meant less rain got into continental regions affected by monsoons over time.”
Eventually, these monsoon-based rivers held too little water and dried, making them unfavorable for civilization.
“The Harappans were an enterprising people taking advantage of a window of opportunity — a kind of “Goldilocks civilization,” Giosan said.
Eventually, over the course of centuries, Harappans apparently fled along an escape route to the east toward the Ganges basin, where monsoon rains remained reliable.
“We can envision that this eastern shift involved a change to more localized forms of economy — smaller communities supported by local rain-fed farming and dwindling streams,” Fuller said. “This may have produced smaller surpluses, and would not have supported large cities, but would have been reliable.”
This change would have spelled disaster for the cities of the Indus, which were built on the large surpluses seen during the earlier, wetter era. The dispersal of the population to the east would have meant there was no longer a concentrated workforce to support urbanism.
“Cities collapsed, but smaller agricultural communities were sustainable and flourished,” Fuller said. “Many of the urban arts, such as writing, faded away, but agriculture continued and actually diversified.”
They did have to put in a little something about global warming/climate change at the end of the article.
It remains uncertain how monsoons will react to modern climate change. “If we take the devastating floods that caused the largest humanitarian disaster in Pakistan’s history as a sign of increased monsoon activity, than this doesn’t bode well for the region,” Giosan said. “The region has the largest irrigation scheme in the world, and all those dams and channels would become obsolete in the face of the large floods an increased monsoon would bring.”
But this is an important point and I think a whole lot more research needs to be done on changes in climate in the past. I suspect that the rise and fall of empires has as much to do with the energy output of the sun and changing winds and currents as anything humans can do.
- Huge Ancient Civilization’s Collapse Explained (livescience.com)
- An Ancient Civilization, Upended by Climate Change (green.blogs.nytimes.com)
- Harappans may have lived, died by monsoon (sciencenews.org)
- Ancient Civilizations (socyberty.com)
- Climate change led to collapse of ancient Indus civilization, study finds (eurekalert.org)