Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


El Nino unusually active in the late 20th century

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."

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.

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:, +852 3917-7101, The University of Hong Kong. Shang-Ping Xie, currently at:, (858) 822-0053, Scripps Institution of Oceanography.

International Pacific Research Center Media Contact: Gisela E. Speidel, (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.

Talia S Ogliore | EurekAlert!
Further information:

More articles from Earth Sciences:

nachricht Wandering greenhouse gas
16.03.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht Unique Insights into the Antarctic Ice Shelf System
14.03.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

A new kind of quantum bits in two dimensions

19.03.2018 | Physics and Astronomy

Scientists have a new way to gauge the growth of nanowires

19.03.2018 | Materials Sciences

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Science & Research
Overview of more VideoLinks >>>