Featured Research

from universities, journals, and other organizations

El Nino Impacts: Weaker In The Past, Stronger In The Future?

Date:
January 12, 1999
Source:
National Center For Atmospheric Research (NCAR)
Summary:
El Nino may have been less of a factor in Northern Hemisphere climate around 4000 B.C. than it is now, and global warming may be working to accentuate El Nino's current and future impacts. National Center for Atmospheric Research scientists are uncovering implications for world climate.

DALLAS--El Nino may have been less of a factor in Northern Hemisphereclimate around 4000 B.C. than it is now, and global warming may beworking to accentuate El Nino's current and future impacts. Theseconclusions by two scientists at the National Center for AtmosphericResearch (NCAR) will be presented along with other research on the ElNino/Southern Oscillation (ENSO) on January 13 at the AmericanMeteorological Society (AMS) annual meeting in Dallas, Texas.

Related Articles


Bette Otto-Bliesner used NCAR's recently developed climate system model(CSM) to study the behavior of ENSO, which affects much of the globe,and the North Atlantic Oscillation (NAO), a more regional cycle thatalters temperatures and precipitation across the northwest Atlantic andEurope. She found that the impacts of ENSO on Northern Hemispherewinters (for instance, a general warming across Canada and the northernU.S. during El Nino) were up to 50% weaker 6,000 years ago. Her researchwas funded by the National Science Foundation (NSF), NCAR's primarysponsor.

To reproduce the climate of 4000 B.C., Otto-Bliesner altered theincoming solar radiation to account for the planet's greater tilt and ashift in perihelion (the earth's closest annual approach to the sun) atthat time. The result is accentuated seasonality, with up to 6% moresolar input during the Northern Hemisphere summer and a correspondingreduction in the winter. As a control run, Otto-Bliesner used the CSM tosimulate present-day conditions. In both the 4,000 B.C. and present-dayruns, the model captured the ebb and flow of El Nino and La Nina, butthe impacts of ENSO were considerably weaker in the 4,000 B.C. run.

What about the future of El Nino? According to NCAR senior scientistKevin Trenberth, ENSO's impacts may be enhanced by human-producedclimate change. El Ninos have been unusually frequent since the mid-1970s. The same period has seen a dramatic rise in global temperature.The year 1998 set a global record and was one of the United States' twowarmest years since records began in the late 1800s.

Trenberth has found that the global mean temperature peaks three to fourmonths after the peak in El Nino. "It is no coincidence that theexceptional warmth in the first seven months of 1998 occurred as thePacific Ocean lost heat following the peak of the 1997-98 El Nino inDecember 1997," notes Trenberth. During El Ninos, warm waters spreadacross the tropical Pacific, evaporating large amounts of water vaporthat release heat when the vapor condenses into clouds and rain. Thus,El Nino events tend to transfer heat from ocean to atmosphere, warmingthe globe about 0.1 degree Celsius for each standard deviation ofdeparture from average temperatures in the Southern Oscillation index,according to Trenberth.

Trenberth theorizes that much of the additional heat trapped byincreasing amounts of greenhouse gases may be going into the oceans. Itis later released through El Ninos that are larger, more frequent, orless efficient in releasing the ocean-stored heat. The atmosphericwarming induced by El Nino also helps to further dry out regions alreadyprone to drought during El Nino, such as Indonesia, Australia, and partsof Africa and Brazil. "Naturally occurring droughts, such as from ENSO,are likely to set in quicker, plants will wilt sooner, and the droughtsmay become more extensive and last longer with global warming."Trenberth's work was sponsored by the National Oceanic and AtmosphericAdministration's Office of Global Programs, the National Aeronautics andSpace Administration, and NSF.

NCAR is sponsored by NSF and managed by the University Corporation forAtmospheric Research, a consortium of more than 60 universities offeringPh.D.s in atmospheric and related sciences.

-The End-

Writer: Bob Henson

Find this news release on the World Wide Web athttp://www.ucar.edu/publications/newsreleases/1999/amsenso.html

To receive UCAR and NCAR news releases by e-mail, telephone303-497-8601 or send name, affiliation, snail-mail address, fax, andphone number to butterwo@ucar.edu


Story Source:

The above story is based on materials provided by National Center For Atmospheric Research (NCAR). Note: Materials may be edited for content and length.


Cite This Page:

National Center For Atmospheric Research (NCAR). "El Nino Impacts: Weaker In The Past, Stronger In The Future?." ScienceDaily. ScienceDaily, 12 January 1999. <www.sciencedaily.com/releases/1999/01/990111180607.htm>.
National Center For Atmospheric Research (NCAR). (1999, January 12). El Nino Impacts: Weaker In The Past, Stronger In The Future?. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/1999/01/990111180607.htm
National Center For Atmospheric Research (NCAR). "El Nino Impacts: Weaker In The Past, Stronger In The Future?." ScienceDaily. www.sciencedaily.com/releases/1999/01/990111180607.htm (accessed October 24, 2014).

Share This



More Earth & Climate News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) — Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Raw: Tornado Rips Roofs in Washington State

Raw: Tornado Rips Roofs in Washington State

AP (Oct. 24, 2014) — A rare tornado ripped roofs off buildings, uprooted trees and shattered windows Thursday afternoon in the southwest Washington city of Longview, but there were no reports of injuries. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) — One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
E.U. Leaders Agree To 40% CO2 Emissions Cut By 2030

E.U. Leaders Agree To 40% CO2 Emissions Cut By 2030

Newsy (Oct. 23, 2014) — The latest E.U. emissions deal calls for a 40 percent greenhouse gas cut, which leaders say sets Europe up to lead in climate negotiations next year. Video provided by Newsy
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:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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