(Press-News.org) Spawning droughts, floods, and other weather disturbances world-wide, the El Niño – Southern Oscillation (ENSO) impacts the daily life of millions of people. During El Niño, Atlantic hurricane activity wanes and rainfall in Hawaii decreases while Pacific winter storms shift southward, elevating the risk of floods in California.
The ability to forecast how ENSO will respond to global warming thus matters greatly to society. Providing accurate predictions, though, is challenging because ENSO varies naturally over decades and centuries. Instrumental records are too short to determine whether any changes seen recently are simply natural or attributable to man-made greenhouse gases. Reconstructions of ENSO behavior are usually missing adequate records for the tropics where ENSO develops.
Help is now underway in the form of a tree-ring record reflecting ENSO activity over the past seven centuries. Tree-rings have been shown to be very good proxies for temperature and rainfall measurements. An international team of scientists spearheaded by Jinbao Li and Shang-Ping Xie, while working at the International Pacific Research Center, University of Hawaii at Manoa, has compiled 2,222 tree-ring chronologies of the past seven centuries from both the tropics and mid-latitudes in both hemispheres. Their work is published in the June 30, 2013 online issue of Nature Climate Change.
The inclusion of tropical tree-ring records enabled the team to generate an archive of ENSO activity of unprecedented accuracy, as attested by the close correspondence with records from equatorial Pacific corals and with an independent Northern Hemisphere temperature reconstruction that captures well-known teleconnection climate patterns.
These proxy records all indicate that ENSO was unusually active in the late 20th century compared to the past seven centuries, implying that this climate phenomenon is responding to ongoing global warming.
"In the year after a large tropical volcanic eruption, our record shows that the east-central tropical Pacific is unusually cool, followed by unusual warming one year later. Like greenhouse gases, volcanic aerosols perturb the Earth's radiation balance. This supports the idea that the unusually high ENSO activity in the late 20th century is a footprint of global warming" explains lead author Jinbao Li.
"Many climate models do not reflect the strong ENSO response to global warming that we found," says co-author Shang-Ping Xie, meteorology professor at the International Pacific Research Center, University of Hawaii at Manoa and Roger Revelle Professor at Scripps Institution of Oceanography, University of California at San Diego. "This suggests that many models underestimate the sensitivity to radiative perturbations in greenhouse gases. Our results now provide a guide to improve the accuracy of climate models and their projections of future ENSO activity. If this trend of increasing ENSO activity continues, we expect to see more weather extremes such as floods and droughts."
INFORMATION:
Citation: Li, J., S.-P. Xie, E. R. Cook, M. Morales, D. Christie, N. Johnson, F. Chen, R. D'Arrigo, A. Fowler, X. Gou, and K. Fang (2013): El Niño modulations over the past seven centuries. Nature Climate Change.
http://dx.doi.org/10.1038/nclimate1936
This research was funded by the National Science Foundation, the National Basic Research Program of China (2012CB955600), the National Oceanic and Atmospheric Administration, the Japan Agency for Marine-Earth Science and Technology, FONDECYT (No.1120965), CONICYT/FONDAP/15110009, CONICET and IAI (CRN2047).
Author Contact:
Jinbao Li, currently at: jinbao@hku.hk, +852 3917-7101, The University of Hong Kong.
Shang-Ping Xie, currently at: sxie@ucsd.edu, (858) 822-0053, Scripps Institution of Oceanography.
International Pacific Research Center Media Contact: Gisela E. Speidel, gspeidel@hawaii.edu. (808) 956- 9252.
The International Pacific Research Center (IPRC) of the School of Ocean and Earth Science and Technology (SOEST) at the University of Hawaii at Manoa, is a climate research center founded to gain greater understanding of the climate system and the nature and causes of climate variation in the Asia-Pacific region and how global climate changes may affect the region. Established under the "U.S.-Japan Common Agenda for Cooperation in Global Perspective" in October 1997, the IPRC is a collaborative effort between agencies in Japan and the United States.
El Nino unusually active in the late 20th century
2013-07-01
ELSE PRESS RELEASES FROM THIS DATE:
Can watching an avatar translate to real-life weight loss?
2013-07-01
WASHINGTON, DC—An estimated two-thirds of all Americans are overweight or obese and many find it difficult to lose weight and keep it off. They've tried fad diets, exercise programs, diet pills and other methods but the battle continues. Now, a new study suggests that watching an avatar model weight-loss behavior in a virtual community might help some women shed pounds in the real world.
"This pilot study showed that you don't have to be a gamer to use virtual reality to learn some important skills for weight loss," said Melissa Napolitano, PhD, an associate professor ...
ATS publishes statement on organ donation after circulatory determination of death
2013-07-01
The American Thoracic Society has released an official statement on the ethical and health policy considerations surrounding adult and pediatric controlled organ donation after circulatory determination of death (DCDD), the recovery of organs after cessation of circulation from patients with severe neurological, neuromuscular or pulmonary disease for whom decisions are made to forego additional life-prolonging treatments.
The ATS developed the statement with input from the Society of Critical Care Medicine, the International Society for Heart and Lung Transplantation, ...
DNDi and Cipla advance development of pediatric 4-in-1 ARVs to fulfill new WHO guidelines
2013-06-30
The World Health Organization's new HIV treatment guidelines, released today at the 2013 International AIDS Society (IAS) Conference, include new antiretroviral (ARV) therapy (ART) recommendations for HIV-infected children, and will mean that more children will be on better treatments. The Drugs for Neglected Diseases initiative (DNDi) applauds the new guidelines and, with Cipla Ltd. and other partners, is expediting the development of urgently needed 4-in-1 ARVs adapted for babies and toddlers with HIV, to be delivered by 2015.
The new 2013 WHO Consolidated Guidelines ...
Biomarker predicts risk of breast cancer recurrence after tamoxifen treatment
2013-06-29
A biomarker reflecting expression levels of two genes in tumor tissue may be able to predict which women treated for estrogen-receptor (ER)-positive breast cancer should receive a second estrogen-blocking medication after completing tamoxifen treatment. In their report being published online in the Journal of the National Cancer Institute, Massachusetts General Hospital (MGH) Cancer Center investigators describe finding that the HOXB13/IL17BR ratio can indicate which women are at risk for cancer recurrence after tamoxifen and which are most likely to benefit from continuing ...
Late bedtimes and less sleep may lead to weight gain in healthy adults
2013-06-29
DARIEN, IL – A new study suggests that healthy adults with late bedtimes and chronic sleep restriction may be more susceptible to weight gain due to the increased consumption of calories during late-night hours.
In the largest, most diverse healthy sample studied to date under controlled laboratory conditions, results show that sleep-restricted subjects who spent only four hours in bed from 4 a.m. to 8 a.m. for five consecutive nights gained more weight than control subjects who were in bed for 10 hours each night from 10 p.m. to 8 a.m. The study found an overall increase ...
Survival of the Galapagos sea lion
2013-06-29
IMMUNE systems of endangered Galapagos sea lions are in overdrive because of harmful activity by people, reveal scientists from the Zoological Society of London (ZSL).
The study shows that Galapagos sea lions (Zalophus wollebaeki) are more prone to starvation because of exposure to human influences like pets and pollution. These can impair the level of their immunity, making them less able to hunt and more likely to go hungry when food is scarce.
This research is published today (28th June) in the journal PLOS ONE.
Conservationists spent more than eighteen months ...
Pre-existing insomnia linked to PTSD and other mental disorders after military deployment
2013-06-29
PHILADELPHIA - A new study from the Perelman School of Medicine at the University of Pennsylvania and the Naval Health Research Center has shown military service members who have trouble sleeping prior to deployments may be at greater risk of developing posttraumatic stress disorder (PTSD), depression and anxiety once they return home. The new study, published in the July 2013 edition of the journal SLEEP, found that pre-existing insomnia symptoms conferred almost as a large of a risk for those mental disorders as combat exposure.
"Understanding environmental and behavioral ...
Disney Research automates analysis of field hockey team behaviors
2013-06-29
Investigators at Disney Research, Pittsburgh, have developed an automated technique for analyzing the patterns of play of field hockey teams, providing a new tool for coaches and commentators who must make sense of mountains of video and other game data.
Because players constantly change roles during the flow of play – a left winger switching temporarily with a right winger, or vice versa – the researchers found that focusing on player roles, rather than the identity of an individual, was best for detecting the tactics, strategy and style of play for each team. The ...
Cardiac patients given longer prescriptions at discharge more likely to continue taking medication
2013-06-29
Elderly cardiac patients prescribed heart medications for 60 days or more after leaving hospital have four times the odds of adhering to the drug regime than patients prescribed the same medications for 30 days, according to research conducted at the Institute for Clinical Evaluative Sciences (ICES) and Women's College Hospital (WCH).
The study, published today in the Canadian Journal of Cardiology, found longer initial prescriptions when leaving hospital are associated with long-term adherence in elderly patients. The findings suggest prescriptions covering a longer ...
Divorce early in childhood affects parental relationships in adulthood
2013-06-29
June 28, 2013 - Divorce has a bigger impact on child-parent relationships if it occurs in the first few years of the child's life, according to new research. Those who experience parental divorce early in their childhood tend to have more insecure relationships with their parents as adults than those who experience divorce later, researchers say.
"By studying variation in parental divorce, we are hoping to learn more about how early experiences predict the quality of people's close relationships later in life," says R. Chris Fraley of the University of Illinois at Urbana-Champaign. ...