Australian scientists have developed an innovative method using cores drilled from coral to produce a world first 400-year long seasonal record of El Niño events, a record that many in the field had described as impossible to extract.
The record published today in Nature Geoscience detects different types of El Niño and shows that the nature of El Niño events has changed in recent decades.
This understanding of El Niño events is vital because they produce extreme weather across the globe with particularly profound effects on precipitation and temperature extremes in Australia, South East Asia and the Americas.
The 400-year record revealed a clear change in El Niño types, with an increase of Central Pacific El Niño activity in the late 20thCentury and suggested future changes ot the strength of Eastern Pacifc El Niños.
“We are seeing more El Niños forming in the central Pacific Ocean in recent decades, which is unusual across the past 400 years,” said lead author Dr Mandy Freund.
“There are even some early hints that the much stronger Eastern Pacific El Niños, like those that occurred in 1997/98 and 2015/16 may be growing in intensity.”
This extraordinary result was teased out of information about past climate from coral cores spanning the Pacific Ocean, as part of Dr. Freund’s PhD research at the University of Melbourne and the Centre of Excellence for Climate Extremes. It was made possible because coral cores – like tree rings – have centuries-long growth patterns and contain isotopes that can tell us a lot about the climate of the past. However, until now, they had not been used to detect the different types of El Niño events.
This meant El Niño researchers were constrained by what they could say about El Niño behavior because the instrumental record was too short and it was hard to judge whether recent decadal changes were exceptional.
“By understanding the past, we are better equipped to understand the future, especially in the context of climate change,” said Dr Freund.
“Prior to this research, we did not know how frequently different types of El Niño occurred in past centuries. Now we do,” said co-author from the Centre of Excellence for Climate Extremes Dr Ben Henley.
The key to unlocking the El Niño record was the understanding that coral records contained enough information to identify seasonal changes in the tropical Pacific Ocean. However, using coral records to reconstruct El Niño history at a seasonal timescale had never been done before and in fact many people working in the field considered it impossible.
It was only after Dr Freund took her innovative approach to a team of climate scientists and coral experts: Dr Ben Henley, Prof David Karoly, Assoc Prof Helen McGregor, Assoc Prof Nerilie Abram, and Dr Dietmar Dommenget that they were able to proceed with the idea.
While the approach was considered challenging, leading Australian experts on past corals, Dr McGregor and Assoc Prof Abram, said that, while the approach might be unconventional, it was worth a shot.
After carefully refining the technique to reconstruct the signature of El Niño in space and time using new machine learning techniques, the scientists were able to compare recent coral results with the instrumental record. Dr Freund found a strong agreement between the coral cores and recorded events. This confirmation allowed the team to extend the record back in time.
Dr Freund and her team found there has been an unprecedented increase in the number of El Niños forming in the Central Pacific over the past 30 years, compared to all 30 year periods in the past 400 years.
At the same time the stronger Eastern Pacific El Niños were the most intense El Niño events ever recorded, according to both the 100-year long instrumental record and the 400-year long coral record.
As a result, Australian researchers have produced a world-first seasonal El Niño record extending 400 years and a new methodology that will likely be the basis for future climate research.
It took three years of hard work to achieve the result and now Dr Freund and her team are excited to see how this work can be built upon.
“The El Niño phenomenon is one of the most important features of global climate, and changes to its behaviour have very serious implications for weather patterns and extreme events around the world,” said Dr Henley.
And that centuries long record opens a door not just to past changes but changes to El Niños in the future as well.
“This gives us an opportunity to more accurately explore how global warming may change El Niños and what this means for future weather and climate extremes.” said Dr Henley.
“Having a better understanding of how different types of El Niños have affected us in the past and present, will mean we are more able to model, predict and plan for future El Niños and their wide ranging impacts,” said Dr Freund.
The Latest on: El Niño
via Google News
The Latest on: El Niño
Weather event similar to El Nino may bring more heatwave episodes to India
on May 18, 2019 at 1:22 am
PUNE: The frequency of heatwaves and their duration in India may start increasing from as early as 2020, says a study by the Pune-based Indian Institute of Tropical Meteorology (IITM). 'El Nino ... […]
El Niño may lessen number of Atlantic hurricanes this upcoming season
on May 16, 2019 at 6:45 am
Check out this story on floridatoday.com: https://www.floridatoday.com/story/news/2019/05/15/el-nino-may-lessen-number-atlantic-hurricanes-upcoming-season/3668755002/ ... […]
El Niño may lessen number of Atlantic hurricanes this season
on May 15, 2019 at 7:13 pm
WEST PALM BEACH, Fla. – Will El Niño's wind shear help dampen the upcoming Atlantic hurricane season, decreasing the odds of another catastrophic landfall like Florence and Michael last year? Phil ... […]
As El Niño Plays Villain, Could the Indian Ocean Dipole Save Monsoon 2019?
on May 14, 2019 at 8:11 pm
with a Nino 3.4 index of 0.7. (Generally, a value between 0.5 and 1 is linked to weak ENSO and a value of less than 0.5 signifies neutral conditions.) So El Niño, in its weak form, is looming ... […]
El Nino Is Weakening, But Where Are The Potential Crop Problem Areas For Commodities?
on May 14, 2019 at 8:07 am
Midwest flooding for corn planting worsening. Spring wheat also to be affected. Our longer term bear market attitude in soybeans has come to fruition, but market a bit oversold ahead of the 2019 ... […]
What a lingering El Niño weather pattern means for Dallas-Fort Worth this summer
on May 9, 2019 at 9:07 am
An El Niño that formed this spring is likely to continue into the summer and possibly linger into the fall, according to the National Oceanic and Atmospheric Administration. NOAA announced Thursday ... […]
El Nino Seen Lingering Through August, Easing Hurricane Threats
on May 9, 2019 at 6:00 am
The weak El Nino pattern that’s been influencing global weather will probably stick around through August, likely bringing rain to Brazil’s coffee fields while drying India’s monsoon and possibly ... […]
New El Nino Record Reveals It Has Gotten Worse Over The Last 400 Years
on May 8, 2019 at 5:34 am
The first seasonal record distinguishing types of el Nino events over the last 400 years says the pattern has dramatically changed in recent years. ... […]
New study reveals “extraordinary change” in El Niño possibly linked to climate change
on May 7, 2019 at 6:35 pm
In a first, researchers have used chemical fingerprints locked within coral skeletons to build a season-by-season record of El Niño episodes dating back 400 years — a feat many experts ... […]
El Niño Is Now Stronger and Stranger, Coral Records Show
on May 7, 2019 at 3:10 pm
The pattern of El Niño has changed dramatically in recent years, according to the first seasonal record distinguishing different types of El Niño events over the last 400 years. A new category of El ... […]
via Bing News