Indus Civilization Collapse Due to Heat

Ruins of Harappa in the Indus valley of today's Pakistan.

New research indicates that a cycle of global warming brought an end to the massive Indus civilization.

"Antiquity knew about Egypt and Mesopotamia, but the Indus civilization, which was bigger than these two, was completely forgotten until the 1920s," says researcher Liviu Giosan, a geologist at Woods Hole Oceanographic Institution in Massachusetts.

He and others are using indicators such as river sediment to track the effects of climate on the civilization.

According to LiveScience.com:

"Our research provides one of the clearest examples of climate change leading to the collapse of an entire civilization,” Giosan said. 

The researchers first analyzed satellite data of the landscape influenced by the Indus and neighboring rivers. From 2003 to 2008, the researchers then collected samples of sediment from the coast of the Arabian Sea into the fertile irrigated valleys of Punjab and the northern Thar Desert to determine the origins and ages of those sediments and develop a timeline of landscape changes. 

"It was challenging working in the desert — temperatures were over 110 degrees Fahrenheit all day long (43 degrees C)," Giosan recalled.

These findings are expected to influence where future archaeological explorations will be conducted regarding the development and fate of the Indus civilization.

Click here for the article.

Scientists Link Biblical Plagues to Climate Change

Plagues of Egypt by Joseph Turner, 1800.

Researchers have found evidence of natural disasters that could have precipitated the Biblical10 plagues of Egypt. They claim the plagues ~ which led to Moses freeing the Israelites from slavery in the Book of Exodus ~ can be attributed to changes in the climate and environmental disasters that happened hundreds of miles away.

Archaeologists now say the plagues occurred at an ancient city of Pi-Rameses on the Nile Delta, the capital of Egypt during the reign of Rameses the Second, between 1279 BC and 1213 BC. The city was abandoned around 3,000 years ago.

Climatologists have discovered that a dramatic shift in the climate in the area occurred towards the end of Rameses the Second's reign, moving from a warm and wet climate to an extended dry period.

"Pharaoh Rameses II reigned during a very favourable climatic period,” says Augusto Magini, a paleoclimatologist at Heidelberg University. "There was plenty of rain and his country flourished. However, this wet period only lasted a few decades. After Rameses' reign, the climate curve goes sharply downwards. There is a dry period which would certainly have had serious consequences."

The scientists believe this switch in the climate was the trigger for the first of the plagues.

Click here for the complete London Telegraph article.

Some Scientists Rejecting Comet-Collision Theory

A prolonged frigid period led to extinction of mastodons and many other creatures, as well as the human Clovis culture.

While scientists are not disputing the existence of a frigid period known as the Younger Dryas about 12,900 years ago, an increasing number are now rejecting the theory that it was caused by Earth’s collision with a comet.

The frigid period ~ whatever its cause ~ is linked to extinction of sabertooths, mastodons, and other giant animals, and may have caused the decline of the Clovis culture.

The comet-collision theory was developed in 2007 and based on a combination of archaeological artifacts and extraterrestrial magnetic grains in soil samples found in a thin layer of sediment throughout North America. However new research, presented at a meeting of the Geological Society of America this week in Portland, Oregon, has taken aim at all of these findings.

Nicholas Pinter, a geologist at Southern Illinois University, argued that black mats described as charcoal in the 2007 research weren't actually charcoal, but were formed from ancient, dark soil formed in a long-ago wetland. Likewise, the small amounts of carbon "are not uniquely associated with high-intensity fire," he said.

According to National Geographic:

Vance Holliday, an archaeologist at the University of Arizona, added that there is no sign that the demise of the Clovis culture was caused by a comet crash.

Around the time of the cold snap, the style of spearpoints changed—which some scientists argued was evidence that the Clovis peoples had declined due to the comet impact. But Holliday said it reflects a normal evolution in preference. He compared spearpoint designs to the appearance—and disappearance—of tail fins on classic automobiles.

"We really don't know what style means in the archaeological record," Holliday said. "Tastes come and go. We don't know why." But "an extraterrestrial impact is an unnecessary solution for an archaeological problem that doesn't exist."

Click here for the National Geographic article.

Water System Contributed to Angkor Demise

Monks on the temple steps of Angkor Wat.

International scientists using new archeological, pollen and tree-ring dating evidence contend that Angkor crumbled due to urban sprawl and extreme weather conditions.

Sydney University archeologist Roland Fletcher ~ a co-director of the Greater Angkor Project, an initiative involving Cambodian, French and Australian experts ~ said he believed the new findings carry "clear implications for modern cities."

The scientists believe that before an alternating series of droughts and monsoon floods hit Angkor from the mid-14th to late 15th centuries, the capital of the Khmer empire had already had extensive problems with its vast, complicated water system.

Ultimately, it became impossible for the city to keep pace with further pressures from extreme weather. Although there was ongoing conflict with neighboring states, it was the over-built water infrastructure that locked Angkor into a trajectory of decline.

Before Angkor vanished into the jungle in the 17th century, it was the world's largest low-density pre-industrial city. Between the ninth and 13th centuries, the metropolis was home to as many as 750,000 people.

Click here for the article in The Australian.

Monsoons Affected Dynasty Health and Decline

Scientists studying a 1,800-year-old stalagmite in China have determined that a severe lack of rainfall likely caused social unrest contributing to the downfall of the Tang, Yuan and Ming dynasties. Conversely, periods of heavier summer monsoons prevailed during China’s “golden age” Northern Song Dynasty.

"The waxing and waning of summer monsoon rains are just one piece of the puzzle of changing climate and culture around the world," said Larry Edwards, geologist at the University of Minnesota and a co-author of the paper appearing in the journal Science. The study was a cooperative effort of the University of Minnesota and Lanzhou University in China.

The work rests on climate data preserved in a 118-millimeter-long stalagmite found in Wanxiang Cave in China’s Gansu Province. It was formed over 1,810 years, with stone at its base dates from190 AD, and stone at its tip from 2003, the year the stalagmite was collected. By measuring amounts of the elements uranium and thorium throughout the stalagmite, researchers can correlate amounts of rainfall ~ a measure of summer monsoon strength ~ to specific timeframes.

"Summer monsoon winds originate in the Indian Ocean and sweep into China," said Hai Cheng, author of the paper and a scientist at the University of Minnesota. "When the summer monsoon is stronger, it pushes farther northwest into China."

According to an article on Science Daily:

A lack of rainfall could have contributed to social upheaval and the fall of dynasties. The researchers discovered that periods of weak summer monsoons coincided with the last years of the Tang, Yuan and Ming dynasties, which are known to have been times of popular unrest.

Conversely, the scientists found that a strong summer monsoon prevailed during one of China's "golden ages," the Northern Song Dynasty. The ample summer monsoon rains may have contributed to the rapid expansion of rice cultivation from southern China to the midsection of the country. During the Northern Song Dynasty, rice first became China's main staple crop, and China's population doubled.

For example, the study showed that the dry period at the end of the Tang Dynasty coincided with a previously identified drought halfway around the world, in Meso-America, which has been linked to the fall of the Mayan civilization.

The study also showed that the ample summer rains of the Northern Song Dynasty coincided with the beginning of the well-known Medieval Warm Period in Europe and Greenland. During this time--the late 10th century--Vikings colonized southern Greenland. Centuries later, a series of weak monsoons prevailed as Europe and Greenland shivered through what geologists call the Little Ice Age.

Click here for the complete article on Science Daily.

The National Science Foundation is correlating data on Asians monsoons, temperatures across the Northern Hemisphere and Alpine glacier growth and retreats, with historical societal developments.