Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Was El Niño unaffected by the Little Ice Age ?


An extremely intense El Niño event in 1983 prompted an international surveillance programme, involving the deployment of moored or drift measurement buoys and observation satellites. This research effort is proving to be fruitful. The data obtained provide a key to understanding how the two components of the now-famous two-phase system El Niño Southern Oscillation (ENSO) -El Niño and its reverse counterpart La Niña- are generated. Forecasting models for three months in advance are quite reliable. However, the knowledge acquired comes from observations which are limited in time and therefore cannot reveal any longer-term variability in the Pacific climate. This is particularly so for ENSO prediction as its strength and phasing can vary widely over a given century or from one century to another. It is therefore difficult now to determine the impact of the present-day global warming on El Niño.

With the aim of improving climate models, research teams are studying periods of the past during which the climate was different from that of the present day. They are investigating especially the extent to which the ENSO phenomenon occurred at the time with the same frequency and intensity. IRD scientists from the Nouméa centre, in conjunction with the College of Marine Science (University of South Florida), have studied a colony of Porites (massive corals) which has been building up since the mid XVIIth century. This colony yields pure signals, by way of trace element analysis involving coupled Sr/Ca and U/Ca ratio determination, on the changes in the sea surface temperature (SST) that have occurred over 350 years.
The team focused its attention on a particularly cold period (1701-1761), which occurred in the middle of the Little Ice Age (1400 to 1850 A.D.). At this time, temperatures in temperate latitudes of the Northern Hemisphere were between 1 and 2 °C lower than average figures recorded at present. Drill-core coral samples taken from near the Amédée Lighthouse on the South-West side of New Caledonia show that the Little Ice Age also prevailed in the tropical South-West Pacific, with an average cooling of around 1°C. Was El Niño, which now manifests itself in this area of the Pacific every two to seven years by a fall in SSTs (by 0.5 to 1.5°C), reinforced by this generalized cooling? The reconstitution of a composite monthly SST record over the first 60 years of the XVIIIth century has led the researchers to some surprising observations. El Niño’s behaviour then was similar to what it is now. In spite of a decrease in average temperatures, neither the strength nor the frequency of El Niño therefore appears to have been affected, even during the very coldest period.

The New Caledonia corals have, however, recorded a much more pronounced interdecadal oscillation (a period of 15 to 20 years) than is now observed : in 1720, 1730 and 1748 in particular decreases in annual average SSTs exceeded 1°C. This is an important result. The scientific community is now considering if there is interaction between El Niño (which recurs every 2 to 7 years) and lower-frequency climatic phenomena (recurrence every 10 to 60 years). The Amédée Lighthouse corals may not have shed new light on that, but they have proved they can yield useful information on these low-frequency cycles over time.

1. Massive corals are considered as the best memory of climatic variability of the tropical oceans. The coral skeleton incorporates a continual record, sometimes covering several centuries, of temperature, salinity and sunshine fluctuations. The fast formation rate and the existence of seasonal growth bands make them an ideal material for studying recent palaeoclimatology in relation with El Niño.
2. A 1°C decrease in average annual temperatures.

Marie-Lise Sabrie | alphagalileo
Further information:

More articles from Earth Sciences:

nachricht Ice shelf vibrations cause unusual waves in Antarctic atmosphere
25.10.2016 | American Geophysical Union

nachricht Enormous dome in central Andes driven by huge magma body beneath it
25.10.2016 | University of California - Santa Cruz

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Ice shelf vibrations cause unusual waves in Antarctic atmosphere

25.10.2016 | Earth Sciences

Fluorescent holography: Upending the world of biological imaging

25.10.2016 | Power and Electrical Engineering

Etching Microstructures with Lasers

25.10.2016 | Process Engineering

More VideoLinks >>>