Navigation Links
War, plague no match for deforestation in driving CO2 buildup
Date:1/20/2011

Stanford, CA Genghis Khan and his Mongol hordes had an impact on the global carbon cycle as big as today's annual demand for gasoline. The Black Death, on the other hand, came and went too quickly for it to cause much of a blip in the global carbon budget. Dwarfing both of these events, however, has been the historical trend towards increasing deforestation, which over centuries has released vast amounts of carbon dioxide into the atmosphere, as crop and pasture lands expanded to feed growing human populations. Even Genghis Kahn couldn't stop it for long.

"It's a common misconception that the human impact on climate began with the large-scale burning of coal and oil in the industrial era," says Julia Pongratz of the Carnegie Institution's Department of Global Ecology, lead author of a new study on the impact of historical events on global climate published in the January 20, 2011, online issue of The Holocene. "Actually, humans started to influence the environment thousands of years ago by changing the vegetation cover of the Earth's landscapes when we cleared forests for agriculture."

Clearing forests releases carbon dioxide into the atmosphere when the trees and other vegetation are burned or when they decay. The rise in atmospheric carbon dioxide resulting from deforestation is recognizable in ice cores from Greenland and Antarctica before the fossil-fuel era.

But human history has had its ups and downs. During high-mortality events, such as wars and plagues, large areas of croplands and pastures have been abandoned and forests have re-grown, absorbing carbon dioxide from the atmosphere.

Pongratz decided to see how much effect these events could have had on the overall trend of rising carbon dioxide levels. Working with colleagues at the Max Planck Institute for Meteorology in Germany and with global ecologist Ken Caldeira at Carnegie, she compiled a detailed reconstruction of global land cover over the time period from 800 AD to present and used a global climate-carbon cycle model to track the impact of land use changes on global climate. Pongratz was particularly interested in four major events in which large regions were depopulated: the Mongol invasions in Asia (1200-1380), the Black Death in Europe (1347-1400), the conquest of the Americas (1519-1700), and the Fall of the Ming Dynasty in China (1600-1650).

"We found that during the short events such as the Black Death and the Ming Dynasty collapse, the forest re-growth wasn't enough to overcome the emissions from decaying material in the soil," says Pongratz. "But during the longer-lasting ones like the Mongol invasion and the conquest of the Americas there was enough time for the forests to re-grow and absorb significant amounts of carbon."

The global impact of forest re-growth in even the long-lasting events was diminished by the continued clearing of forests elsewhere in the world. But in the case of the Mongol invasions, which had the biggest impact of the four events studied, re-growth on depopulated lands stockpiled nearly 700 million tons of carbon absorbed from the atmosphere. This is equivalent to the world's total annual demand for gasoline today.

Pongratz points out the relevance of the study to current climate issues. "Today about a quarter of the net primary production on the Earth's land surface is used by humans in some way, mostly through agriculture," she says. "So there is a large potential for our land-use choices to alter the global carbon cycle. In the past we have had a substantial impact on global climate and the carbon cycle, but it was all unintentional. Based on the knowledge we have gained from the past, we are now in a position to make land-use decisions that will diminish our impact on climate and the carbon cycle. We cannot ignore the knowledge we have gained."


'/>"/>

Contact: Julia Pongratz
pongratz@carnegie.stanford.edu
650-919-4358
Carnegie Institution
Source:Eurekalert

Related biology news :

1. Carnivorous mice spread deadly plague in prairie dog towns, Stanford study finds
2. Scientists discover 21st century plague
3. New MegaMatcher 4.0 from Neurotechnology Integrates Fingerprint, Iris, Facial and Palmprint Biometrics In One High-Performance SDK
4. MegaMatcher Accelerator 3.0 for Rapid Biometric Identification Matches Up to 200 Million Irises or 100 Million Fingerprints Per Second
5. Study shows real partners are no match for ideal mate
6. To a mosquito, matchmaking means singing in perfect harmony
7. New VeriLook 4.0 for Biometric Facial Recognition and MegaMatcher 3.1 for Multi-biometric Applications Are Now Available
8. Gene mismatch influences success of bone marrow transplants
9. IRSF receives $1 million matching gift
10. WCC Smart Search & Match and Priv-ID Announce Global Collaboration
11. Blood-flow metabolism mismatch predicts pancreatic tumor aggressiveness
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/9/2017)... FRANCISCO and MOUNTAIN VIEW, Calif. ... , "Eating Well Made Simple," and 23andMe , ... help guide better food choices.  Zipongo can now provide ... their food preferences, health goals and biometrics, but also ... certain food choices. Zipongo,s personalized food decision ...
(Date:3/2/2017)... , March 2, 2017 Summary This ... Perrigo and its partnering interests and activities since 2010. ... Read the ... and Alliance since 2010 report provides an in-depth insight into ... sciences companies. On demand company reports are prepared ...
(Date:3/1/2017)... 2017  Aware, Inc. (NASDAQ: AWRE), a leading supplier ... P. Moberg has resigned, effective March 3, 2017, ... Officer and Treasurer of Aware citing a desire to ... member of the Board of Directors of Aware. ... Officer and co-President, General Counsel has been named Chief ...
Breaking Biology News(10 mins):
(Date:3/30/2017)... Pharmaceuticals plc (Nasdaq: JAZZ ) today announced ... Shinyaku, Co., Ltd. for Defitelio ® (defibrotide sodium) ... or CPX-351, in Japan . ... will receive exclusive rights to develop and commercialize Defitelio ... return for an upfront payment to Jazz Pharmaceuticals and ...
(Date:3/29/2017)... ... March 29, 2017 , ... Zansors announced today its ... issued by the U.S. Patent & Trademark Office (USPTO). The patent covers a ... health monitoring. This invention will be critical to the future of wearable tech ...
(Date:3/29/2017)... March 29, 2017  Vermillion, Inc. (NASDAQ: VRML), ... reported on its results for the fourth quarter ... "2016 marked a pivotal year for us ... inclusion, international distribution agreements, major reimbursement progress with ... payer agreements. In addition we cleared our 2 ...
(Date:3/29/2017)... SPRINGS, CO , March 29, 2017 /PRNewswire/ - Last year,s ... support kratom are not the only efforts active to generate awareness ... substitute opiate based pharmaceutical drugs in the healthcare market place. ... Earlier this month ... based developer and distributor of pharmaceutical and nutritional products, announced its ...
Breaking Biology Technology: