Recent El Ninos Unlikely To Be Caused By Past Warming Trend

March 09, 1998

The global temperature increases this century are unlikely to be the cause of the spate of El Niño events during the 1990s, according to CSIRO scientist Dr Rob Allan.

"We know that El Niño tends to occur every two to seven years,’ says Dr Allan.

‘I have found two additional longer climatic fluctuations linked with El Niño: one occurs every eleven to thirteen years; the other, every fifteen to twenty years,’ says Dr Allan, from the CSIRO Division of Atmospheric Research.

‘These climatic fluctuations have probably occurred for thousands of years,’ says Dr Allan.

‘This makes me think that the gradual warming we’ve seen around the globe this century is unlikely to be the cause of the recent series of El Niño events,’ says Dr Allan.

‘The dominant influences governing the strength and occurrence of El Niño are the three climatic fluctuations and other natural climatic variations,’ says Dr Allan.

‘I know my results will add to debate in the scientific community about the behaviour of El Niño,’ says Dr Allan.

To reach his conclusion, Dr Allan analysed global atmospheric pressure and sea-surface temperature data collected during the past 125 years from almost seven hundred land locations and from numerous ship measurements.

Dr Allan’s research marks a major advance in understanding the nature and structure of El Niño and is an important step towards resolving the physical mechanisms that give rise to the El Niño cycle. The research will also help establish what influence the greenhouse effect might have on El Niño.

‘Agricultural scientists are keen to explore the potential for using this new understanding of El Niño to improve farm management strategies to deal with drought and floods,’ says Dr Allan.

Dr Allan recently returned from an eight month visit to the Hadley Centre at the United Kingdom Meteorological Office, where he worked with prominent British scientists tracking down and analysing extensive climatic records from a wide range of sources.

‘One of the more interesting records I found was a dog-eared exercise book containing nineteenth century weather reports compiled by British missionaries in Uganda,’ says Dr Allan.

CSIRO is now running climate models to assess likely future changes to El Niño caused by increasing levels of greenhouse gases such as carbon dioxide. The climate models, which are run on a powerful supercomputer, incorporate the behaviour of the oceans and the atmosphere, which are crucial to the formation of El Niño. Model simulations show that El Niño events are features of climate that can be expected to continue in future under greenhouse conditions.

Dr Allan and colleagues recently published an atlas featuring global historical atmospheric pressure and sea-surface temperature maps detailing every El Niño event since 1871.

CSIRO Australia

Related Climate Models Articles from Brightsurf:

Polar ice, atmospheric water vapor biggest drivers of variation among climate models
A Florida State University researcher is part of a team that has found varying projections on global warming trends put forth by climate change scientists can be explained by differing models' predictions regarding ice loss and atmospheric water vapor.

Revising climate models with new aerosol field data
Advanced field measurements of how quickly aerosol particles are pulled out of the air can help improve climate predictions - and air quality forecasts.

Simpler models may be better for determining some climate risk
Typically, computer models of climate become more and more complex as researchers strive to capture more details of our Earth's system, but according to a team of Penn State researchers, to assess risks, less complex models, with their ability to better sample uncertainties, may be a better choice.

Atmospheric scientists study fires to resolve ice question in climate models
Black carbon from fires is an important short-term climate driver because it can affect the formation and composition of clouds.

New soil models may ease atmospheric CO2, climate change
To remove carbon dioxide from the Earth's atmosphere in an effort to slow climate change, scientists must get their hands dirty and peek underground.

Patterns in permafrost soils could help climate change models
A team of scientists spent the past four summers measuring permafrost soils across a 5,000 square-mile swath of Alaska's North Slope.

Latest climate models show more intense droughts to come
An analysis of new climate model projections by Australian researchers from the ARC Centre of Excellence for Climate Extremes shows southwestern Australia and parts of southern Australia will see longer and more intense droughts due to a lack of rainfall caused by climate change.

Some of the latest climate models provide unrealistically high projections of future warming
A new study from University of Michigan climate researchers concludes that some of the latest-generation climate models may be overly sensitive to carbon dioxide increases and therefore project future warming that is unrealistically high.

A Europe covered in grasslands or forests: innovation and research on climate models
An experiment to better understand how atmospheric variables respond to land use changes.

How tiny water droplets form can have a big impact on climate models
Droplets and bubbles are formed nearly everywhere, from boiling our morning coffee, to complex industrial processes and even volcanic eruptions.

Read More: Climate Models News and Climate Models Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to