Featured Research

from universities, journals, and other organizations

Ancient catastrophic drought leads to question: How severe can climate change become?

Date:
February 24, 2011
Source:
National Science Foundation
Summary:
How severe can climate change become in a warming world? Worse than anything we've seen in written history, according to results of a study. An international team of scientists has compiled four dozen paleoclimate records from sediment cores in Lake Tanganyika and other locations in Africa. The records show that one of the most widespread and intense droughts of the last 50,000 years or more struck Africa and Southern Asia 17,000 to 16,000 years ago.

A wetland along Lake Victoria today, analogous to ancient drought conditions.
Credit: Curt Stager

How severe can climate change become in a warming world? Worse than anything we've seen in written history, according to results of a study recently appearing in the journal Science.

An international team of scientists led by Curt Stager of Paul Smith's College, New York, has compiled four dozen paleoclimate records from sediment cores in Lake Tanganyika and other locations in Africa.

The records show that one of the most widespread and intense droughts of the last 50,000 years or more struck Africa and Southern Asia 17,000 to 16,000 years ago.

Between 18,000 and 15,000 years ago, large amounts of ice and meltwater entered the North Atlantic Ocean, causing regional cooling but also major drought in the tropics, says Paul Filmer, program director in the National Science Foundation's (NSF) Division of Earth Sciences, which funded the research along with NSF's Division of Atmospheric and Geospace Sciences and its Division of Ocean Sciences.

"The height of this time period coincided with one of the most extreme megadroughts of the last 50,000 years in the Afro-Asian monsoon region with potentially serious consequences for the Paleolithic humans that lived there at the time," says Filmer.

The "H1 megadrought," as it's known, was one of the most severe climate trials ever faced by anatomically modern humans.

Africa's Lake Victoria, now the world's largest tropical lake, dried out, as did Lake Tana in Ethiopia, and Lake Van in Turkey.

The Nile, Congo and other major rivers shriveled, and Asian summer monsoons weakened or failed from China to the Mediterranean, meaning the monsoon season carried little or no rainwater.

What caused the megadrought remains a mystery, but its timing suggests a link to Heinrich Event 1 (or "H1"), a massive surge of icebergs and meltwater into the North Atlantic at the close of the last ice age.

Previous studies had implicated southward drift of the tropical rain belt as a localized cause, but the broad geographic coverage in this study paints a more nuanced picture.

"If southward drift were the only cause," says Stager, lead author of the Science paper, "we'd have found evidence of wetting farther south. But the megadrought hit equatorial and southeastern Africa as well, so the rain belt didn't just move--it also weakened."

Climate models have yet to simulate the full scope of the event.

The lack of a complete explanation opens the question of whether an extreme megadrought could strike again as the world warms and de-ices further.

"There's much less ice left to collapse into the North Atlantic now," Stager says, "so I'd be surprised if it could all happen again--at least on such a huge scale."

Given what such a catastrophic megadrought could do to today's most densely populated regions of the globe, Stager hopes he's right.

Stager also holds an adjunct position at the Climate Change Institute, University of Maine, Orono.

Co-authors of the paper are David Ryves of Loughborough University in the United Kingdom; Brian Chase of the Institut des Sciences de l'Evolution de Montpellier in France and the Department of Archaeology, University of Bergen, Norway; and Francesco Pausata of the Geophysical Institute, University of Bergen, Norway.


Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. Curt Stager, David B. Ryves, Brian M. Chase, and Francesco S. R. Pausata. Catastrophic Drought in the Afro-Asian Monsoon Region During Heinrich Event 1. Science, 24 February 2011 DOI: 10.1126/science.1198322

Cite This Page:

National Science Foundation. "Ancient catastrophic drought leads to question: How severe can climate change become?." ScienceDaily. ScienceDaily, 24 February 2011. <www.sciencedaily.com/releases/2011/02/110224145649.htm>.
National Science Foundation. (2011, February 24). Ancient catastrophic drought leads to question: How severe can climate change become?. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2011/02/110224145649.htm
National Science Foundation. "Ancient catastrophic drought leads to question: How severe can climate change become?." ScienceDaily. www.sciencedaily.com/releases/2011/02/110224145649.htm (accessed August 29, 2014).

Share This




More Earth & Climate News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Volcano Erupts on Papua New Guinea

Raw: Volcano Erupts on Papua New Guinea

AP (Aug. 29, 2014) — Several communities were evacuated and some international flights were diverted on Friday after one of the most active volcanos in the region erupts. (Aug. 29) Video provided by AP
Powered by NewsLook.com
Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) — State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Scientists Have Figured Out Why Rocks Move In Death Valley

Scientists Have Figured Out Why Rocks Move In Death Valley

Newsy (Aug. 28, 2014) — The mystery of the moving rocks in Death Valley, California, has finally been solved. Scientists are pointing to a combo of water, ice and wind. Video provided by Newsy
Powered by NewsLook.com
Big Waves, Minor Flooding from Hurricane

Big Waves, Minor Flooding from Hurricane

AP (Aug. 27, 2014) — Thundering surf spawned by Hurricane Marie pounded the Southern California coast Wednesday, causing minor flooding in a low-lying beach town. High surf warnings were posted for Los Angeles County south through Orange County. (Aug. 27) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins