Evidence of 900-yr-old mega drought period found
Washington: Researchers at the University of Arizona have revealed a previously unknown multi-decade drought period in the second century A.D after studying oldest pine trees.
Almost nine hundred years ago, in the mid-12th century, the southwestern U.S. was in the middle of a multi-decade megadrought. It was the most recent extended period of severe drought known for this region. But it was not the first.
The second century A.D. saw an extended dry period of more than 100 years characterized by a multi-decade drought lasting nearly 50 years, said scientists at the University of Arizona’s Laboratory of Tree-Ring Research.
UA geoscientists Cody Routson, Connie Woodhouse and Jonathan Overpeck conducted a study of the southern San Juan Mountains in south-central Colorado.
To develop their chronology, the researchers looked for indications of climate in the past in the growth rings of the oldest trees in the southern San Juan region.
Literally nothing is older than a bristlecone pine tree: The oldest and longest-living species on the planet, these pine trees normally are found clinging to bare rocky landscapes of alpine or near-alpine mountain slopes.
The trees, the oldest of which are more than 4,000 years old, are capable of withstanding extreme drought conditions.
“We did a lot of hiking and found a couple of sites of bristlecone pines, and one in particular that we honed in on,” said Routson.
“In our chronology for the south San Juan mountains we created a record that extends back 2,200 years,” he stated.
The chronology extends many years earlier than the medieval period, during which two major drought events in that region already were known from previous chronologies.
“This new record shows that in addition to known droughts from the medieval period, there is also evidence for an earlier megadrought during the second century A.D,” revealed Routson.
“What we can see from our record is that it was a period of basically 50 consecutive years of below-average growth. And that’s within a much broader period that extends from around 124 A.D. to 210 A.D. – about a 100-year-long period of dry conditions,” he added.
The study will be published in Geophysical Research Letters.
More from India
More from World
More from Sports
More from Entertaiment
- Rajasthan: Gujjars revive reservation agitation, block rail track
- J Jayalalithaa sworn-in as Chief Minister of Tamil Nadu
- Dr Subhash Chandra Show: Aspiring for more than what you have!
- ISIS to buy first nuclear weapon from Pak?
- Mumbai: CCTV captures assailant with gun at Film City
- Mathura SSP receives death threat letter, message for PM Modi
- BJP now central pole of Indian politics: Arun Jaitley
- Maharashtra FDA sends Maggi noodles for lab testing
- Watch: Fast N Facts @ 7:30pm
- Haridwar: Hotel Radisson Blu sealed for polluting Ganga
- Delhi: Two killed in road accident in New Ashok Nagar
- Girl in Punjab's Pathankot quit studies for fear of eve-teasing
- Reservation issue: Police register case against Bainsla, 20 others
- Special: Furious over rising water crisis, people take to the streets
- Fiji: Floating island restaurant in middle of ocean
- Goa Board SSC Exam Results 2015 announced
- ISIS close to buying nuclear weapon from Pakistan?
- Manohar Parrikar visits forward areas along LoC, reviews security situation
- Credibility of Prime Minister's Office restored by BJP, says Arun Jaitley
- There will be no delay in appointing CIC, CVC: Jitendra Singh
- ISIS justifies raping slave girls, says Michelle Obama is 'worth $40'
- 'Unhappy' Celina Jaitley asks Sunny Leone to move out?
- Arvind Kejriwal to highlight AAP govt's 100 days work on Monday
- IPL 2015 Final: Mumbai Indians vs Chennai Super Kings - Preview
- BJP's plan for one-year celebration: 200 big rallies, 5,000 public meetings
- CBSE Results 2015: 10th board exam results to be declared on May 27
- Heatwave leaves 153 dead in Telangana, Andhra Pradesh
- IPL 8 Final: We need to be at our best against Mumbai, says Michael Hussey
- Jayalalithaa returns as Tamil Nadu CM: As it happened
- Heatwave kills 223 in AP, Telangana, Chandrababu Naidu announces compensation; Delhi records hottest day